1
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Domingues TS, Coifman R, Haji-Akbari A. Estimating Position-Dependent and Anisotropic Diffusivity Tensors from Molecular Dynamics Trajectories: Existing Methods and Future Outlook. J Chem Theory Comput 2024; 20:4427-4455. [PMID: 38815171 DOI: 10.1021/acs.jctc.4c00148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
Confinement can substantially alter the physicochemical properties of materials by breaking translational isotropy and rendering all physical properties position-dependent. Molecular dynamics (MD) simulations have proven instrumental in characterizing such spatial heterogeneities and probing the impact of confinement on materials' properties. For static properties, this is a straightforward task and can be achieved via simple spatial binning. Such an approach, however, cannot be readily applied to transport coefficients due to lack of natural extensions of autocorrelations used for their calculation in the bulk. The prime example of this challenge is diffusivity, which, in the bulk, can be readily estimated from the particles' mobility statistics, which satisfy the Fokker-Planck equation. Under confinement, however, such statistics will follow the Smoluchowski equation, which lacks a closed-form analytical solution. This brief review explores the rich history of estimating profiles of the diffusivity tensor from MD simulations and discusses various approximate methods and algorithms developed for this purpose. Besides discussing heuristic extensions of bulk methods, we overview more rigorous algorithms, including kernel-based methods, Bayesian approaches, and operator discretization techniques. Additionally, we outline methods based on applying biasing potentials or imposing constraints on tracer particles. Finally, we discuss approaches that estimate diffusivity from mean first passage time or committor probability profiles, a conceptual framework originally developed in the context of collective variable spaces describing rare events in computational chemistry and biology. In summary, this paper offers a concise survey of diverse approaches for estimating diffusivity from MD trajectories, highlighting challenges and opportunities in this area.
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Affiliation(s)
- Tiago S Domingues
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Ronald Coifman
- Department of Mathematics, Yale University, New Haven, Connecticut 06520, United States
- Department of Computer Science, Yale University, New Haven, Connecticut 06520, United States
| | - Amir Haji-Akbari
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
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2
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Tu YJ, Peng ST. Influence of surface nanostructure-induced innermost ion structuring on capacitance of carbon/ionic liquid double layers. Phys Chem Chem Phys 2024; 26:5932-5946. [PMID: 38299635 DOI: 10.1039/d3cp05617a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
Ionic liquids have drawn great interest as electrolytes for energy storage applications in which they form characteristic electrical double layers at electrode interfaces. For ionic liquids at carbon electrode interfaces, their double layers are subject to nanoscale structuring of the electrode surface, involving altered ion structure and interactions that significantly influence the double layer capacitance. In this regard, we investigate the modulation of ionic liquid double layers by electrode surface roughness and the resulting effects on the ion structure, interaction, and capacitance. We performed fixed voltage molecular dynamics simulations to compute the differential capacitance profiles for the ionic liquids [BMIm+][TFSI-] and [BMIm+][FSI-] at model carbon electrode interfaces with the surface channel width at subnanometer and nanometer scales. We find that both [BMIm+][TFSI-] and [BMIm+][FSI-] exhibit enhanced differential capacitance for the electrode surface with a subnanometer channel width relative to the flat graphene surface, but the most pronounced enhancements for these two ionic liquids unexpectedly appear at different applied potential regimes. For [BMIm+][TFSI-], the nanostructured electrode shows significant enhancement of capacitance at high positive potential. For [BMIm+][FSI-], on the other hand, this enhancement is small at positive polarization but noticeable at low negative potential. We demonstrate that differences in these capacitance trends is due to differences in ion correlation that arise from a steric constraint of nanostructured electrode surface on the voltage-mediated restructuring of ions closest to the electrode interface. For example, the TFSI- and FSI- anions tend to structure with their charged and nonpolar groups in contact with the positive electrode surface when the constraint on these close-contact anions is relaxed. This anion structuring largely retains the cation association near the nanostructured electrode, resulting in only a slight increase in capacitance at positive polarization. Our simulations highlight the sensitive dependence of the innermost ion structure on the electrode surface nanostructure and applied voltage and the resulting influence on ion correlation and capacitance of ionic liquid double layers.
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Affiliation(s)
- Yi-Jung Tu
- Department of Applied Chemistry, National Chi Nan University, Puli, Nantou, 54561, Taiwan.
| | - Sheng-Ting Peng
- Department of Applied Chemistry, National Chi Nan University, Puli, Nantou, 54561, Taiwan.
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3
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Imanishi A. Preparation of Nanoparticles and Diffusion Behavior of Metal Ions in Ionic Liquids. CHEM REC 2023; 23:e202300110. [PMID: 37194965 DOI: 10.1002/tcr.202300110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/03/2023] [Indexed: 05/18/2023]
Abstract
Ionic liquids (ILs) have attracted much attention as tunable liquids because of their unique structures and properties. However, the mechanisms of chemical reactions and solute diffusion in ionic liquids are still unknown. This article summarizes our previous studies and recent results on the mechanisms of metal particle formation and solute diffusion in ionic liquids, focusing on the local structure of ionic liquids. It was found that the shape and size of metal particles formed in ionic liquids using electron beams or X-rays are strongly influenced by the local structure. In the study of the diffusion behavior of metal ions in ionic liquids, we proposed a hopping-like diffusion model and proposed that this behavior could be strongly influenced by local structures such as hole concentration and/or domain structures.
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Affiliation(s)
- Akihito Imanishi
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
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4
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Bonagiri LKS, Panse KS, Zhou S, Wu H, Aluru NR, Zhang Y. Real-Space Charge Density Profiling of Electrode-Electrolyte Interfaces with Angstrom Depth Resolution. ACS NANO 2022; 16:19594-19604. [PMID: 36351178 DOI: 10.1021/acsnano.2c10819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The accumulation and depletion of charges at electrode-electrolyte interfaces is crucial for all types of electrochemical processes. However, the spatial profile of such interfacial charges remains largely elusive. Here we develop charge profiling three-dimensional (3D) atomic force microscopy (CP-3D-AFM) to experimentally quantify the real-space charge distribution of the electrode surface and electric double layers (EDLs) with angstrom depth resolution. We first measure the 3D force maps at different electrode potentials using our recently developed electrochemical 3D-AFM. Through statistical analysis, peak deconvolution, and electrostatic calculations, we derive the depth profile of the local charge density. We perform such charge profiling for two types of emergent electrolytes, ionic liquids, and highly concentrated aqueous solutions, observe pronounced sub-nanometer charge variations, and find the integrated charge densities to agree with those derived from macroscopic electrochemical measurements.
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Affiliation(s)
- Lalith Krishna Samanth Bonagiri
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
| | - Kaustubh S Panse
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
| | - Shan Zhou
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
| | - Haiyi Wu
- Walker Department of Mechanical Engineering and Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, Texas78712, United States
| | - Narayana R Aluru
- Walker Department of Mechanical Engineering and Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, Texas78712, United States
| | - Yingjie Zhang
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
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5
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Panse KS, Wu H, Zhou S, Zhao F, Aluru NR, Zhang Y. Innermost Ion Association Configuration Is a Key Structural Descriptor of Ionic Liquids at Electrified Interfaces. J Phys Chem Lett 2022; 13:9464-9472. [PMID: 36198103 DOI: 10.1021/acs.jpclett.2c02768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The structure of electric double layers (EDLs) is crucial for all types of electrochemical processes. While in dilute solutions EDL structure can be approximately treated within the Gouy-Chapman-Stern regime, in highly ionic electrolytes the description of EDL has been largely elusive. Here we study the EDL structure of an ionic liquid on a series of crystalline electrodes. Through molecular dynamics (MD) simulations, we observe strong intermolecular interaction among cations and anions and propose that the cation-anion association structure at the innermost layer is a key descriptor of the EDL. Using our recently developed electrochemical 3D atomic force microscopy (EC-3D-AFM) technique, we confirm the theoretical prediction and further find that the width of the first EDL is an experimental gauge of the ion association structure in that layer. We expect such ion association descriptors to be broadly applicable to a large range of highly ionic electrolytes on various electrode surfaces.
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Affiliation(s)
- Kaustubh S Panse
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
| | - Haiyi Wu
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas78712, United States
- Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, Texas78712, United States
| | - Shan Zhou
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
| | - Fujia Zhao
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
| | - Narayana R Aluru
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas78712, United States
- Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, Texas78712, United States
| | - Yingjie Zhang
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
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6
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Chen Z, Li Z, Zhao W, Matsumoto RA, Thompson MW, Morales-Collazo O, Cummings PT, Mangolini F, Brennecke JF. Investigation of Multilayered Structures of Ionic Liquids on Graphite and Platinum Using Atomic Force Microscopy and Molecular Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:4036-4047. [PMID: 35313730 DOI: 10.1021/acs.langmuir.2c00024] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The molecular-level orientation and structure of ionic liquids (ILs) at liquid-solid interfaces are significantly different than in the bulk. The interfacial ordering influences both IL properties, such as dielectric constants and viscosity, and their efficacy in devices, such as fuel cells and electrical capacitors. Here, we report the layered structures of four ILs on unbiased, highly ordered pyrolytic graphite (HOPG) and Pt(111) surfaces, as determined by atomic force microscopy. The ILs investigated are 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]), 1-ethyl-3-methylimidazolium perfluorobutylsulfonate ([emim][C4F9SO3]), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene bis(trifluoromethylsulfonyl)imide ([MTBD][Tf2N]), and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene perfluorobutylsulfonate ([MTBD][C4F9SO3]). Molecular dynamics simulations provide complementary information on the position and orientation of the ions. These ILs form a cation layer at the IL-solid interface, followed by a layer of anions. [Emim]+ and [MTBD]+ have similar orientations at the surface, but [MTBD]+ forms a thinner layer compared to [emim]+ on both HOPG and Pt(111). In addition, [Tf2N]- shows stronger interactions with Pt(111) surfaces than [C4F9SO3]-.
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Affiliation(s)
- Zhichao Chen
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Zixuan Li
- Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, United States
- Materials Science and Engineering Program, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Wei Zhao
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Ray A Matsumoto
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Matthew W Thompson
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Oscar Morales-Collazo
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Peter T Cummings
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Filippo Mangolini
- Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, United States
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Joan F Brennecke
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
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7
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Wang Y, He H, Wang C, Lu Y, Dong K, Huo F, Zhang S. Insights into Ionic Liquids: From Z-Bonds to Quasi-Liquids. JACS AU 2022; 2:543-561. [PMID: 35373210 PMCID: PMC8965826 DOI: 10.1021/jacsau.1c00538] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Indexed: 05/26/2023]
Abstract
Ionic liquids (ILs) hold great promise in the fields of green chemistry, environmental science, and sustainable technology due to their unique properties, such as a tailorable structure, the various types available, and their environmentally friendly features. On the basis of multiscale simulations and experimental characterizations, two unique features of ILs are as follows: (1) strong coupling interactions between the electrostatic forces and hydrogen bonds, namely in the Z-bond, and (2) the unique semiordered structure and properties of ultrathin films, specifically regarding the quasi-liquid. In accordance with the aforementioned theoretical findings, many cutting-edge applications have been proposed: for example, CO2 capture and conversion, biomass conversion and utilization, and energy storage materials. Although substantial progress has been made recently in the field of ILs, considerable challenges remain in understanding the nature of and devising applications for ILs, especially in terms of e.g. in situ/real-time observation and highly precise multiscale simulations of the Z-bond and quasi-liquid. In this Perspective, we review recent developments and challenges for the IL research community and provide insights into the nature and function of ILs, which will facilitate future applications.
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Affiliation(s)
- Yanlei Wang
- Beijing
Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory
of Multiphase Complex Systems, CAS Key Laboratory of Green Process
and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- University
of Chinese Academy of Sciences, Beijing 100049, People’s
Republic of China
| | - Hongyan He
- Beijing
Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory
of Multiphase Complex Systems, CAS Key Laboratory of Green Process
and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- University
of Chinese Academy of Sciences, Beijing 100049, People’s
Republic of China
| | - Chenlu Wang
- Beijing
Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory
of Multiphase Complex Systems, CAS Key Laboratory of Green Process
and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- University
of Chinese Academy of Sciences, Beijing 100049, People’s
Republic of China
| | - Yumiao Lu
- Beijing
Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory
of Multiphase Complex Systems, CAS Key Laboratory of Green Process
and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Kun Dong
- Beijing
Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory
of Multiphase Complex Systems, CAS Key Laboratory of Green Process
and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Feng Huo
- Beijing
Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory
of Multiphase Complex Systems, CAS Key Laboratory of Green Process
and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Suojiang Zhang
- Beijing
Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory
of Multiphase Complex Systems, CAS Key Laboratory of Green Process
and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- University
of Chinese Academy of Sciences, Beijing 100049, People’s
Republic of China
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8
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A Presentation of Ionic Liquids as Lubricants: Some Critical Comments. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11125677] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ionic liquids (ILs) are liquid materials at room temperature with an ionic intrinsic nature. The electrostatic interactions therefore play a pivotal role in dictating their inner structure, which is then expected to be far from the traditional pattern of classical simple liquids. Therefore, the strength of such interactions and their long-range effects are responsible for the ionic liquid high viscosity, a fact that itself suggests their possible use as lubricants. More interestingly, the possibility to establish a wide scenario of possible interactions with solid surfaces constitutes a specific added value in this use. In this framework, the ionic liquid complex molecular structure and the huge variety of possible interactions cause a complex aggregation pattern which can depend on the presence of the solid surface itself. Although there is plenty of literature focusing on the lubricant properties of ionic liquids and their applications, the aim of this contribution is, instead, to furnish to the reader a panoramic view of this exciting problematic, commenting on interesting and speculative aspects which are sometimes neglected in standard works and trying to furnish an enriched vision of the topic. The present work constitutes an easy-to-read critical point of view which tries to interact with the imagination of readers, hopefully leading to the discovery of novel aspects and interconnections and ultimately stimulating new ideas and research.
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9
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An S, Lee M, Jhe W. Probing the shear viscoelasticity of a nanoscale ionic liquid meniscus. Phys Chem Chem Phys 2021; 23:12387-12394. [PMID: 34027528 DOI: 10.1039/d0cp06003h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Ionic liquids (ILs) are emerging as novel solvents that exhibit peculiar mechanical properties in the form of thin films on metal surfaces under normal pressure. However, the mechanical properties of ILs in the form of nano-meniscus have not been analyzed yet. Here, we investigate the shear viscoelasticity of a single IL meniscus at the nanoscale. To characterize the shear rheological properties of ILs, we employ a quartz tuning fork-based atomic force microscope, conduct dynamic force spectroscopy, and analyse shear properties using the non-Newtonian-Maxwell model. The elastic response of the IL nanomeniscus is found to be about 25 times higher than that of the bulk IL bridge, whereas the viscous responses are similar. In addition, by conducting shear velocity-dependent measurements, we find that the IL meniscus shows nonlinear rheological behaviours. Interestingly, we observe that the relaxation time of the IL increases at a tip-substrate distance of about 60 nm.
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Affiliation(s)
- Sangmin An
- Department of Physics & Astronomy, Center for 0D Nanofluidics, Institute of Applied Physics, Seoul National University, Seoul 08826, Korea. and Department of Physics, Research Institute of Physics and Chemistry, Jeonbuk National University, Jeonju 54896, Korea
| | - Manhee Lee
- Department of Physics, Chungbuk National University, Cheongju, Chungbuk 28644, Korea
| | - Wonho Jhe
- Department of Physics & Astronomy, Center for 0D Nanofluidics, Institute of Applied Physics, Seoul National University, Seoul 08826, Korea.
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10
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Gao Q, Tsai W, Balke N. In situ and operando force‐based atomic force microscopy for probing local functionality in energy storage materials. ELECTROCHEMICAL SCIENCE ADVANCES 2021. [DOI: 10.1002/elsa.202100038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Qiang Gao
- Department of Chemistry University of Wisconsin‐Madison Madison Wisconsin USA
| | - Wan‐Yu Tsai
- Chemical Science Division Oak Ridge National Laboratory Oak Ridge Tennessee USA
| | - Nina Balke
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge Tennessee USA
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11
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Zhai J, Sarkar S, Tran N, Pandiancherri S, Greaves TL, Drummond CJ. Tuning Nanostructured Lyotropic Liquid Crystalline Mesophases in Lipid Nanoparticles with Protic Ionic Liquids. J Phys Chem Lett 2021; 12:399-404. [PMID: 33356288 DOI: 10.1021/acs.jpclett.0c03318] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We herein report 13 protic ionic liquids (PILs) as tunable solvation media to regulate the internal lyotropic liquid crystalline mesophase of monoolein-based nanoparticles. A range of nanostructures, including inverse bicontinuous cubic, inverse hexagonal, and sponge/lamellar mesophases, were produced and verified by synchrotron small-angle X-ray scattering. Notably, manipulating the cation/anion structures of the PILs can alter the monoolein packing behavior and cause a sequential phase transition (hexagonal → cubic → lamellar) in the nanoparticles. The solvent channels inside the nanoparticles were enlarged up to 40% under certain PIL-water conditions, making these materials prospective for encapsulation of large molecules. Finally, a freeze-drying study demonstrated the ability of PILs to preserve nanostructure upon reconstitution of the nanoparticles compared to that in pure water. This study opens a new route for fine-tuning lyotropic liquid crystalline structures using PILs, which circumvents issues encountered using conventional salts.
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Affiliation(s)
- Jiali Zhai
- School of Science, College of Science, Engineering and Health, RMIT University, Victoria 3000, Australia
| | - Sampa Sarkar
- School of Science, College of Science, Engineering and Health, RMIT University, Victoria 3000, Australia
| | - Nhiem Tran
- School of Science, College of Science, Engineering and Health, RMIT University, Victoria 3000, Australia
| | - Shveta Pandiancherri
- School of Science, College of Science, Engineering and Health, RMIT University, Victoria 3000, Australia
| | - Tamar L Greaves
- School of Science, College of Science, Engineering and Health, RMIT University, Victoria 3000, Australia
| | - Calum J Drummond
- School of Science, College of Science, Engineering and Health, RMIT University, Victoria 3000, Australia
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12
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Zhou S, Panse KS, Motevaselian MH, Aluru NR, Zhang Y. Three-Dimensional Molecular Mapping of Ionic Liquids at Electrified Interfaces. ACS NANO 2020; 14:17515-17523. [PMID: 33227191 DOI: 10.1021/acsnano.0c07957] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Electric double layers (EDLs), occurring ubiquitously at solid-liquid interfaces, are critical for electrochemical energy conversion and storage processes such as capacitive charging and redox reactions. However, to date the molecular-scale structure of EDLs remains elusive. Here we report an advanced technique, electrochemical three-dimensional atomic force microscopy (EC-3D-AFM), and use it to directly image the molecular-scale EDL structure of an ionic liquid under different electrode potentials. We observe not only multiple discrete ionic layers in the EDL on a graphite electrode but also a quasi-periodic molecular density distribution within each layer. Furthermore, we find pronounced 3D reconfiguration of the EDL at different voltages, especially in the first layer. Combining the experimental results with molecular dynamics simulations, we find potential-dependent molecular redistribution and reorientation in the innermost EDL layer, both of which are critical to EDL capacitive charging. We expect this mechanistic understanding to have profound impacts on the rational design of electrode-electrolyte interfaces for energy conversion and storage.
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Affiliation(s)
- Shan Zhou
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, United States
| | - Kaustubh S Panse
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, United States
| | | | - Narayana R Aluru
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Yingjie Zhang
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, United States
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13
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Chen Z, Tonouchi Y, Matsumoto K, Tsuzuki S, Nagata T, Katahira M, Hagiwara R. Structural evaluation and protium-deuterium exchange in 1-ethyl-3-methylimidazolium halide-ethylene glycol mixtures. J Fluor Chem 2020. [DOI: 10.1016/j.jfluchem.2020.109637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Wang YL, Li B, Sarman S, Mocci F, Lu ZY, Yuan J, Laaksonen A, Fayer MD. Microstructural and Dynamical Heterogeneities in Ionic Liquids. Chem Rev 2020; 120:5798-5877. [PMID: 32292036 PMCID: PMC7349628 DOI: 10.1021/acs.chemrev.9b00693] [Citation(s) in RCA: 197] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation-anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
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Affiliation(s)
- Yong-Lei Wang
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Bin Li
- School
of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China
| | - Sten Sarman
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Francesca Mocci
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy
| | - Zhong-Yuan Lu
- State
Key Laboratory of Supramolecular Structure and Materials, Institute
of Theoretical Chemistry, Jilin University, Changchun 130021, P. R. China
| | - Jiayin Yuan
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Aatto Laaksonen
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
- State
Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
- Centre of
Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry Aleea Grigore Ghica-Voda, 41A, 700487 Iasi, Romania
- Department
of Engineering Sciences and Mathematics, Division of Energy Science, Luleå University of Technology, SE-97187 Luleå, Sweden
| | - Michael D. Fayer
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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15
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Wang Y, Li L. Uncovering the Underlying Mechanisms Governing the Solidlike Layering of Ionic Liquids (ILs) on Mica. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:2743-2756. [PMID: 32101445 DOI: 10.1021/acs.langmuir.9b03865] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Significant progress has been made in understanding the IL-solid interface in the past three decades, and a key finding is that ILs can form solidlike layers at the interface. It has been recognized that the electrostatic forces at the solid-IL interface and self-assembly of ILs are key enablers of the IL layering. However, regarding the layering structure of ILs, research from different laboratories is not consistent; i.e., the number of solidlike layers could range from 0 to ∼60, indicating the complexity of the underlying mechanisms and/or the existence of overlooked key parameters. In the current review, we will discuss the underlying mechanisms and key parameters governing the layering of ILs on mica, the most studied model solid. First, we will present the experimental findings from various laboratories, both consistent and contradictory ones, and summarize the current understanding of the governing mechanisms. Then, we will discuss the possible key parameters, including the structure of ILs, surface modification and contamination of mica, and cosolvent impacting the solidlike layering of ILs. Finally, we will discuss future research directions in uncovering the underlying mechanisms.
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Affiliation(s)
- Yali Wang
- Department of Chemistry and Chemical Engineering, Yulin University, Yulin, Shaanxi, P.R. China 719000
- Department of Chemical & Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Lei Li
- Department of Chemical & Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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16
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Park S, McDaniel JG. Interference of electrical double layers: Confinement effects on structure, dynamics, and screening of ionic liquids. J Chem Phys 2020; 152:074709. [DOI: 10.1063/1.5144260] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Suehyun Park
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
| | - Jesse G. McDaniel
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
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17
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Bhide A, Jagannath B, Tanak A, Willis R, Prasad S. CLIP: Carbon Dioxide testing suitable for Low power microelectronics and IOT interfaces using Room temperature Ionic Liquid Platform. Sci Rep 2020; 10:2557. [PMID: 32054949 PMCID: PMC7018756 DOI: 10.1038/s41598-020-59525-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 01/27/2020] [Indexed: 11/08/2022] Open
Abstract
Health and safety considerations of room occupants in enclosed spaces is crucial for building management which entails control and stringent monitoring of CO2 levels to maintain acceptable air quality standards and improve energy efficiency. Smart building management systems equipped with portable, low-power, non-invasive CO2 sensing techniques can predict room occupancy detection based on CO2 levels exhaled by humans. In this work, we have demonstrated the development and proof-of-feasibility working of an electrochemical RTIL- based sensor prototype for CO2 detection in exhaled human breath. The portability, small form factor, embedded RTIL sensing element, integrability with low-power microelectronic and IOT interfaces makes this CO2 sensor prototype a potential application for passive room occupancy monitoring. This prototype exhibits a wide dynamic range of 400-8000 ppm, a short response time of ~10 secs, and a reset time of ~6 secs in comparison to commercial standards. The calibration response of the prototype exhibits an R2 of 0.956. With RTIL as the sensing element, we have achieved a sensitivity of 29 pF/ppm towards CO2 at ambient environmental conditions and a three times greater selectivity towards CO2 in the presence of N2 and O2. CO2 detection is accomplished by quantifying the capacitance modulations arising within the electrical double layer from the RTIL- CO2 interactions through AC- based electrochemical impedance spectroscopy and DC- based chronoamperometry.
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Affiliation(s)
- Ashlesha Bhide
- Department of Biomedical Engineering, University of Texas at Dallas, 800W Campbell Rd., Richardson, TX, 75080, USA
| | - Badrinath Jagannath
- Department of Biomedical Engineering, University of Texas at Dallas, 800W Campbell Rd., Richardson, TX, 75080, USA
| | - Ambalika Tanak
- Department of Biomedical Engineering, University of Texas at Dallas, 800W Campbell Rd., Richardson, TX, 75080, USA
| | - Richard Willis
- Department of Electrical and Computer Engineering, University of Texas at Dallas, 800W Campbell Rd., Richardson, TX, 75080, USA
| | - Shalini Prasad
- Department of Biomedical Engineering, University of Texas at Dallas, 800W Campbell Rd., Richardson, TX, 75080, USA.
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18
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Lhermerout R, Perkin S. A new methodology for a detailed investigation of quantized friction in ionic liquids. Phys Chem Chem Phys 2020; 22:455-466. [PMID: 31781711 DOI: 10.1039/c9cp05422g] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
When confined at the nanoscale between smooth surfaces, an ionic liquid forms a structured film responding to shear in a quantized way, i.e., with a friction coefficient indexed by the number of layers in the gap. So far, only a few experiments have been performed to study this phenomenon, because of the delicate nature of the measurements. We propose a new methodology to measure friction with a surface force balance, based on the simultaneous application of normal and lateral motions to the surfaces, allowing for a more precise, comprehensive and rapid determination of the friction response. We report on proof-of-concept experiments with an ionic liquid confined between mica surfaces in dry or wet conditions, showing the phenomenon of quantized friction with an unprecedented resolution. First, we show that the variation of the kinetic friction force with the applied load for a given layer is not linear, but can be quantitatively described by two additive contributions that are respectively proportional to the load and to the contact area. Then, we find that humidity improves the resistance of the layers to be squeezed-out and extends the range of loads in which the liquid behaves as a superlubricant, interpreted by an enhanced dissolution of the potassium ions on the mica leading to a larger surface charge. There, we note a liquid-like friction behavior, and observe in certain conditions a clear variation of the kinetic friction force over two decades of shearing velocities, that does not obey a simple Arrhenius dynamics.
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Affiliation(s)
- Romain Lhermerout
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.
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19
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Cai M, Yu Q, Liu W, Zhou F. Ionic liquid lubricants: when chemistry meets tribology. Chem Soc Rev 2020; 49:7753-7818. [PMID: 33135717 DOI: 10.1039/d0cs00126k] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Ionic liquids (ILs) have emerged as potential lubricants in 2001. Subsequently, there has been tremendous research interest in ILs from the tribology society since their discovery as novel synthetic lubricating materials. This also expands the research area of ILs. Consistent with the requirement of searching for alternative and eco-friendly lubricants, IL lubrication will experience further development in the coming years. Herein, we review the research progress of IL lubricants. Generally, the tribological properties of IL lubricants as lubricating oils, additives and thin films are reviewed in detail and their lubrication mechanisms discussed. Considering their actual applications, the flexible design of ILs allows the synthesis of task-specific and tribologically interesting ILs to overcome the drawbacks of the application of ILs, such as high cost, poor compatibility with traditional oils, thermal oxidization and corrosion. Nowadays, increasing research is focused on halogen-free ILs, green ILs, synthesis-free ILs and functional ILs. In addition to their macroscopic properties, the nanoscopic performance of ILs on a small scale and in small gaps is also important in revealing their tribological mechanisms. It has been shown that when sliding surfaces are compressed, in comparison with a less polar molecular lubricant, ion pairs resist "squeeze out" due to the strong interaction between the ions of ILs and oppositely charged surfaces, resulting in a film that remains in place at higher shear forces. Thus, the lubricity of ILs can be externally controlled in situ by applying electric potentials. In summary, ILs demonstrate sufficient design versatility as a type of model lubricant for meeting the requirements of mechanical engineering. Accordingly, their perspectives and future development are discussed in this review.
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Affiliation(s)
- Meirong Cai
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
| | - Qiangliang Yu
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
| | - Weimin Liu
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China. and State Key Laboratory of Solidification Processing, College of Materials Science and Technology, Northwestern Polytechnical University, 127 YouyiXi Road, Xi an 710072, China
| | - Feng Zhou
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
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20
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Niemann T, Li H, Warr GG, Ludwig R, Atkin R. Influence of Hydrogen Bonding between Ions of Like Charge on the Ionic Liquid Interfacial Structure at a Mica Surface. J Phys Chem Lett 2019; 10:7368-7373. [PMID: 31713427 DOI: 10.1021/acs.jpclett.9b03007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ionic liquids (ILs) have attracted increasing interest in science and technology because of their remarkable properties, which can be tuned via varying ion structures to control the relative strengths of Coulomb interactions, hydrogen bonding (H-bonding), and dispersion forces. Here we use atomic force microscopy to probe the interfacial nanostructures of hydroxy functionalized ILs at negatively charged mica surfaces. H-bonding between hydroxy functionalized cations (c-c) produces cation clusters and a stronger interfacial nanostructure. H-bond stabilized cation clusters form despite opposing electrostatic repulsions between charge groups, cation-anion (c-a) electrostatic attractions, and (c-a) H-bonds. Comparison of ILs with and without OH functionalized cations shows directional H-bonding enhances interfacial structure more strongly than the dispersion forces between alkyl groups. These findings reveal a new means of controlling IL interfacial nanostructure via H-bonding between like-charged ions, which impact diverse areas including electrochemical charge storage (batteries and catalysis), electrodeposition, lubrication, etc.
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Affiliation(s)
- Thomas Niemann
- Institut für Chemie, Abteilung für Physikalische Chemie , Universität Rostock , Dr.-Lorenz-Weg 2 , 18059 Rostock , Germany
- Department LL&M , University of Rostock , Albert-Einstein-Str. 25 , 18059 Rostock , Germany
| | - Hua Li
- School of Molecular Sciences , The University of Western Australia , Perth , Western Australia 6009 , Australia
| | - Gregory G Warr
- School of Chemistry and Sydney Nano Institute , The University of Sydney , Camperdown , NSW 2006 , Australia
| | - Ralf Ludwig
- Institut für Chemie, Abteilung für Physikalische Chemie , Universität Rostock , Dr.-Lorenz-Weg 2 , 18059 Rostock , Germany
- Department LL&M , University of Rostock , Albert-Einstein-Str. 25 , 18059 Rostock , Germany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V. , Albert-Einstein-Str. 29a , 18059 Rostock , Germany
| | - Rob Atkin
- School of Molecular Sciences , The University of Western Australia , Perth , Western Australia 6009 , Australia
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21
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Zhao M, Wu B, Lall-Ramnarine SI, Ramdihal JD, Papacostas KA, Fernandez ED, Sumner RA, Margulis CJ, Wishart JF, Castner EW. Structural analysis of ionic liquids with symmetric and asymmetric fluorinated anions. J Chem Phys 2019; 151:074504. [PMID: 31438705 DOI: 10.1063/1.5111643] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Ionic liquids (ILs) with relatively low viscosities and broad windows of electrochemical stability are often constructed by pairing asymmetric cations with bisfluorosulfonylimide (FSI-) or bistriflimide (NTf2 -) anions. In this work, we systematically studied the structures of ILs with these anions and related perfluorobis-sulfonylimide anions with asymmetry and/or longer chains: (fluorosulfonyl)(trifluoromethylsulfonyl)imide (BSI0,1 -), bis(pentafluoroethylsulfonyl)imide (BETI-), and (trifluoromethylsulfonyl) (nonafluorobutylsulfonyl)imide (BSI1,4 -) using high energy X-ray scattering and molecular dynamics simulation methods. 1-alkyl-3-methylimidazolium cations with shorter (ethyl, Im2,1 +) and longer (octyl, Im1,8 +) hydrocarbon chains were selected to examine how the sizes of nonpolar hydrocarbon and fluorous chains affect IL structures and properties. In comparison with these, we also computationally explored the structure of ionic liquids with anions having longer fluorinated tails.
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Affiliation(s)
- Man Zhao
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Boning Wu
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Sharon I Lall-Ramnarine
- Chemistry Department, Queensborough Community College of the City University of New York, Bayside, New York 11364, USA
| | - Jasodra D Ramdihal
- Chemistry Department, Queensborough Community College of the City University of New York, Bayside, New York 11364, USA
| | - Kristina A Papacostas
- Chemistry Department, Queensborough Community College of the City University of New York, Bayside, New York 11364, USA
| | - Eddie D Fernandez
- Chemistry Department, Queensborough Community College of the City University of New York, Bayside, New York 11364, USA
| | - Rawlric A Sumner
- Chemistry Department, Queensborough Community College of the City University of New York, Bayside, New York 11364, USA
| | - Claudio J Margulis
- Department of Chemistry, The University of Iowa, Iowa City, Iowa 52242, USA
| | - James F Wishart
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Edward W Castner
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
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22
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Tang Y, Liu X, McMahan J, Kumar A, Khan A, Sevilla M, Zeng X. Adsorption and Electrochemistry of Carbon Monoxide at the Ionic Liquid-Pt Interface. J Phys Chem B 2019; 123:4726-4734. [PMID: 31041862 DOI: 10.1021/acs.jpcb.8b11602] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this work, CO adsorption and oxidation processes were studied with cyclic voltammetry and anodic adsorptive stripping chronoamperometry in two structural different ionic liquids (ILs) (i.e., 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [Bmpy][NTf2] and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [Bmim][NTf2]). Multiple redox processes were observed in the ILs. During the anodic oxidation processes, the NTf2- anion is oxidized to form NTf2• radical and CO is oxidized to CO2 and produces a proton in these ILs when a trace amount of water is present. The products of oxidation processes (NTf2• radical and proton) can be reduced at cathodic processes. Results show that the cation in these ILs can facilitate the formation of an electrolyte-electrode interface structure that influences the amount of CO adsorbed as well as the subsequent CO oxidation current and charge. By selecting the anodic and cathodic potentials, we developed an innovative electroanalytical method for CO sensing based on a simple double-potential adsorptive stripping chronoamperometry. The method allows calibration of the concurrent NTf2- anion and CO redox processes as well as the double-layer charging and discharging processes in the IL with the presence of a trace amount of water providing quantitative analysis of CO concentration with high accuracy and sensitivity. The reported method is the first work to show that quantitative CO detection can be achieved in the presence of complex dynamic interfacial processes in the ILs. The trace water present in the ILs is beneficial for CO oxidation, but a large amount of water is detrimental for the CO oxidation in ambient condition.
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Affiliation(s)
- Yongan Tang
- Department of Chemistry , Oakland University , Rochester , Michigan 48309 , United States
| | - Xiaojun Liu
- Department of Chemistry , Oakland University , Rochester , Michigan 48309 , United States
| | - Jordan McMahan
- Department of Chemistry , Oakland University , Rochester , Michigan 48309 , United States
| | - Anil Kumar
- Department of Chemistry , Oakland University , Rochester , Michigan 48309 , United States
| | - Asim Khan
- Department of Chemistry , Oakland University , Rochester , Michigan 48309 , United States
| | - Michael Sevilla
- Department of Chemistry , Oakland University , Rochester , Michigan 48309 , United States
| | - Xiangqun Zeng
- Department of Chemistry , Oakland University , Rochester , Michigan 48309 , United States
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23
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Maruyama S, Prastiawan IBH, Toyabe K, Higuchi Y, Koganezawa T, Kubo M, Matsumoto Y. Ionic Conductivity in Ionic Liquid Nano Thin Films. ACS NANO 2018; 12:10509-10517. [PMID: 30199622 DOI: 10.1021/acsnano.8b06386] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Thin film approaches are powerful methods for gaining a nanoscale understanding of interfacial ionic liquids (ILs) in the vicinity of solids. These approaches are used to directly elucidate the interfacial contributions to the physical properties of ILs as nanoscale thin films have significant proportions of the surface or interface region with respect to their total volume. Here, we report the growth of a uniform [emim][TFSA] thin film ionic liquid on a chemically modified, well-wettable sapphire, thereby allowing the in situ measurement of its ionic conductivity on the nanoscale. We observed the thickness-dependent behavior of the ionic conductivity, which gradually decreased especially when the thickness was less than 10 nm, and found it to be quantitatively analyzed well by using an empirical two-layer model. The molecular dynamics (MD) simulations show that the thickness-dependent ionic conductivity originates from the solid-like structuring of the IL near the substrate, reproducing a thickness-dependent ionic conductivity. The MD simulation results suggest that the thickness of the low conductivity region determined in the two-layer model should roughly correspond to the thickness of the solid-like structuring of the IL near the substrate.
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Affiliation(s)
- Shingo Maruyama
- Department of Applied Chemistry, School of Engineering , Tohoku University , Sendai 980-8579 , Japan
| | | | - Kaho Toyabe
- Department of Applied Chemistry, School of Engineering , Tohoku University , Sendai 980-8579 , Japan
| | - Yuji Higuchi
- Institute for Materials Research , Tohoku University , Sendai 980-8577 , Japan
| | - Tomoyuki Koganezawa
- Japan Synchrotron Radiation Research Institute (JASRI) , SPring-8, 1-1-1 Kouto , Sayo , Hyogo 679-5198 , Japan
| | - Momoji Kubo
- Institute for Materials Research , Tohoku University , Sendai 980-8577 , Japan
| | - Yuji Matsumoto
- Department of Applied Chemistry, School of Engineering , Tohoku University , Sendai 980-8579 , Japan
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24
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Shrivastav G, Remsing RC, Kashyap HK. Capillary evaporation of the ionic liquid [EMIM][BF4] in nanoscale solvophobic confinement. J Chem Phys 2018; 148:193810. [PMID: 30307173 DOI: 10.1063/1.5010259] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Gourav Shrivastav
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Richard C. Remsing
- Institute for Computational Molecular Science and Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Hemant K. Kashyap
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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25
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Miyamoto H, Yokota Y, Imanishi A, Inagaki K, Morikawa Y, Fukui KI. Potential dependent changes in the structural and dynamical properties of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide on graphite electrodes revealed by molecular dynamics simulations. Phys Chem Chem Phys 2018; 20:19408-19415. [DOI: 10.1039/c8cp02733a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Surface distributions and the dynamic properties of an ionic liquid on charged graphite electrodes.
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Affiliation(s)
- Hiroo Miyamoto
- Department of Materials Engineering Science
- Graduate School of Engineering Science
- Osaka University
- Toyonaka
- Japan
| | | | - Akihito Imanishi
- Department of Materials Engineering Science
- Graduate School of Engineering Science
- Osaka University
- Toyonaka
- Japan
| | - Kouji Inagaki
- Department of Precision Science and Technology
- Graduate School of Engineering
- Osaka University
- Suita
- Japan
| | - Yoshitada Morikawa
- Department of Precision Science and Technology
- Graduate School of Engineering
- Osaka University
- Suita
- Japan
| | - Ken-ichi Fukui
- Department of Materials Engineering Science
- Graduate School of Engineering Science
- Osaka University
- Toyonaka
- Japan
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26
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Hoffmann V, Pulletikurthi G, Carstens T, Lahiri A, Borodin A, Schammer M, Horstmann B, Latz A, Endres F. Influence of a silver salt on the nanostructure of a Au(111)/ionic liquid interface: an atomic force microscopy study and theoretical concepts. Phys Chem Chem Phys 2018; 20:4760-4771. [DOI: 10.1039/c7cp08243f] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We combine in situ atomic force microscopy and non-equilibrium thermodynamics to investigate the Au(111)/electrolyte interface. Experiment and theory show that the concentration of solutes strongly influences the structure of the electrode/electrolyte interface.
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Affiliation(s)
- Viktor Hoffmann
- Institute of Electrochemistry
- Clausthal University of Technology
- 38678 Clausthal-Zellerfeld
- Germany
| | - Giridhar Pulletikurthi
- Institute of Electrochemistry
- Clausthal University of Technology
- 38678 Clausthal-Zellerfeld
- Germany
| | - Timo Carstens
- Institute of Electrochemistry
- Clausthal University of Technology
- 38678 Clausthal-Zellerfeld
- Germany
| | - Abhishek Lahiri
- Institute of Electrochemistry
- Clausthal University of Technology
- 38678 Clausthal-Zellerfeld
- Germany
| | - Andriy Borodin
- Institute of Electrochemistry
- Clausthal University of Technology
- 38678 Clausthal-Zellerfeld
- Germany
| | - Max Schammer
- Helmholtz Institute Ulm
- 89081 Ulm
- Germany
- German Aerospace Center
- 70569 Stuttgart
| | - Birger Horstmann
- Helmholtz Institute Ulm
- 89081 Ulm
- Germany
- German Aerospace Center
- 70569 Stuttgart
| | - Arnulf Latz
- Helmholtz Institute Ulm
- 89081 Ulm
- Germany
- German Aerospace Center
- 70569 Stuttgart
| | - Frank Endres
- Institute of Electrochemistry
- Clausthal University of Technology
- 38678 Clausthal-Zellerfeld
- Germany
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27
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Tomita K, Mizukami M, Nakano S, Ohta N, Yagi N, Kurihara K. X-Ray diffraction and resonance shear measurement of nano-confined ionic liquids. Phys Chem Chem Phys 2018; 20:13714-13721. [DOI: 10.1039/c7cp08611c] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The X-ray diffraction and resonance shear measurement (RSM) demonstrated the relation between the structure and lubrication properties of ionic liquid ([C4mim][NTf2], [C4mim][BF4]) films of nanometer thickness confined between silica surfaces.
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Affiliation(s)
- Kazuhito Tomita
- Institute of Multidisciplinary Research for Advanced Materials
- Tohoku University
- Sendai 980-8577
- Japan
| | - Masashi Mizukami
- Institute of Multidisciplinary Research for Advanced Materials
- Tohoku University
- Sendai 980-8577
- Japan
| | - Shinya Nakano
- Institute of Multidisciplinary Research for Advanced Materials
- Tohoku University
- Sendai 980-8577
- Japan
| | - Noboru Ohta
- Japan Synchrotron Radiation Research Institute/SPring-8
- Sayo
- Japan
| | - Naoto Yagi
- Japan Synchrotron Radiation Research Institute/SPring-8
- Sayo
- Japan
| | - Kazue Kurihara
- Institute of Multidisciplinary Research for Advanced Materials
- Tohoku University
- Sendai 980-8577
- Japan
- New Industry Creation Hatchery Center
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28
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Balabajew M, van Engers CD, Perkin S. Contact-free calibration of an asymmetric multi-layer interferometer for the surface force balance. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:123903. [PMID: 29289219 DOI: 10.1063/1.5006056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The Surface Force Balance (SFB, also known as Surface Force Apparatus, SFA) has provided important insights into many phenomena within the field of colloid and interface science. The technique relies on using white light interferometry to measure the distance between surfaces with sub-nanometer resolution. Up until now, the determination of the distance between the surfaces required a so-called "contact calibration," an invasive procedure during which the surfaces are brought into mechanical contact. This requirement for a contact calibration limits the range of experimental systems that can be investigated with SFB, for example, it precludes experiments with substrates that would be irreversibly modified or damaged by mechanical contact. Here we present a non-invasive method to measure absolute distances without performing a contact calibration. The method can be used for both "symmetric" and "asymmetric" systems. We foresee many applications for this general approach including, most immediately, experiments using single layer graphene electrodes in the SFB which may be damaged when brought into mechanical contact.
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Affiliation(s)
- Marco Balabajew
- Physical and Theoretical Chemistry Laboratory, Chemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Christian D van Engers
- Physical and Theoretical Chemistry Laboratory, Chemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Susan Perkin
- Physical and Theoretical Chemistry Laboratory, Chemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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29
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Sitaputra W, Stacchiola D, Wishart JF, Wang F, Sadowski JT. In Situ Probing of Ion Ordering at an Electrified Ionic Liquid/Au Interface. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1606357. [PMID: 28498642 DOI: 10.1002/adma.201606357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/27/2017] [Indexed: 06/07/2023]
Abstract
Charge transport at the interface of electrodes and ionic liquids is critical for the use of the latter as electrolytes. A room-temperature ionic liquid, 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide (EMMIM TFSI), is investigated in situ under applied bias voltage with a novel method using low-energy electron and photoemission electron microscopy. Changes in photoelectron yield as a function of bias applied to electrodes provide a direct measure of the dynamics of ion reconfiguration and electrostatic responses of the EMMIM TFSI. Long-range and correlated ionic reconfigurations that occur near the electrodes are found to be a function of temperature and thickness, which, in turn, relate to ionic mobility and different configurations for out-of-plane ordering near the electrode interfaces, with a critical transition in ion mobility for films thicker than three monolayers.
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Affiliation(s)
- Wattaka Sitaputra
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Dario Stacchiola
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - James F Wishart
- Chemistry Division, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Feng Wang
- Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Jerzy T Sadowski
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
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30
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Li H, Rutland MW, Watanabe M, Atkin R. Boundary layer friction of solvate ionic liquids as a function of potential. Faraday Discuss 2017; 199:311-322. [PMID: 28422196 DOI: 10.1039/c6fd00236f] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atomic force microscopy (AFM) has been used to investigate the potential dependent boundary layer friction at solvate ionic liquid (SIL)-highly ordered pyrolytic graphite (HOPG) and SIL-Au(111) interfaces. Friction trace and retrace loops of lithium tetraglyme bis(trifluoromethylsulfonyl)amide (Li(G4) TFSI) at HOPG present clearer stick-slip events at negative potentials than at positive potentials, indicating that a Li+ cation layer adsorbed to the HOPG lattice at negative potentials which enhances stick-slip events. The boundary layer friction data for Li(G4) TFSI shows that at HOPG, friction forces at all potentials are low. The TFSI- anion rich boundary layer at positive potentials is more lubricating than the Li+ cation rich boundary layer at negative potentials. These results suggest that boundary layers at all potentials are smooth and energy is predominantly dissipated via stick-slip events. In contrast, friction at Au(111) for Li(G4) TFSI is significantly higher at positive potentials than at negative potentials, which is comparable to that at HOPG at the same potential. The similarity of boundary layer friction at negatively charged HOPG and Au(111) surfaces indicates that the boundary layer compositions are similar and rich in Li+ cations for both surfaces at negative potentials. However, at Au(111), the TFSI- rich boundary layer is less lubricating than the Li+ rich boundary layer, which implies that anion reorientations rather than stick-slip events are the predominant energy dissipation pathways. This is confirmed by the boundary friction of Li(G4) NO3 at Au(111), which shows similar friction to Li(G4) TFSI at negative potentials due to the same cation rich boundary layer composition, but even higher friction at positive potentials, due to higher energy dissipation in the NO3- rich boundary layer.
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Affiliation(s)
- Hua Li
- Priority Research Centre for Advanced Fluids and Interfaces, The University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Mark W Rutland
- School of Chemical Science and Engineering, KTH Royal Institute of Technology, SE100 44 Sweden and Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden, SE114 86 Sweden
| | - Masayoshi Watanabe
- Department of Chemistry and Biotechnology, Yokohama National University, Yokohama 240-8501, Japan
| | - Rob Atkin
- Priority Research Centre for Advanced Fluids and Interfaces, The University of Newcastle, Callaghan, NSW 2308, Australia.
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31
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Smith AM, Lee AA, Perkin S. Switching the Structural Force in Ionic Liquid-Solvent Mixtures by Varying Composition. PHYSICAL REVIEW LETTERS 2017; 118:096002. [PMID: 28306271 DOI: 10.1103/physrevlett.118.096002] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Indexed: 06/06/2023]
Abstract
The structure and interactions in electrolytes at high concentration have implications from energy storage to biomolecular interactions. However, many experimental observations are yet to be explained in these mixtures, which are far beyond the regime of validity of mean-field models. Here, we study the structural forces in a mixture of ionic liquid and solvent that is miscible in all proportions at room temperature. Using the surface force balance to measure the force between macroscopic smooth surfaces across the liquid mixtures, we uncover an abrupt increase in the wavelength above a threshold ion concentration. Below the threshold concentration, the wavelength is determined by the size of the solvent molecule, whereas above the threshold, it is the diameter of a cation-anion pair that determines the wavelength.
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Affiliation(s)
- Alexander M Smith
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
- Department of Inorganic and Analytical Chemistry, University of Geneva, 1205 Geneva, Switzerland
| | - Alpha A Lee
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Susan Perkin
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
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Affiliation(s)
- Shiguo Zhang
- College
of Materials Science and Engineering, Hunan University, Changsha 410082, China
- Center for Green Chemistry and Catalysis, State Key Laboratory for Oxo Synthesis & Selective Oxidation, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, No.18, Tianshui Middle Road, 730000 Lanzhou, China
| | - Jiaheng Zhang
- School
of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen 518055, China
| | - Yan Zhang
- College
of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Youquan Deng
- Center for Green Chemistry and Catalysis, State Key Laboratory for Oxo Synthesis & Selective Oxidation, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, No.18, Tianshui Middle Road, 730000 Lanzhou, China
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Ionic Liquid Induced Enhancement in the Stickiness of Sticky Dissociative Electroreductive C Cl Bond Cleavage: A Key to Eco-Green Detoxification of Chloroacetonitrile. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.11.084] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Vatamanu J, Vatamanu M, Borodin O, Bedrov D. A comparative study of room temperature ionic liquids and their organic solvent mixtures near charged electrodes. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:464002. [PMID: 27623976 DOI: 10.1088/0953-8984/28/46/464002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The structural properties of electrolytes consisting of solutions of ionic liquids in a polar solvent at charged electrode surfaces are investigated using classical atomistic simulations. The studied electrolytes consisted of tetraethylammonium tetrafluoroborate (NEt4-BF4), 1-ethyl-3-methylimidazolium tetrafluoroborate (c2mim-BF4) and 1-octyl-3-methylimidazolium tetrafluoroborate (c8mim-BF4) salts dissolved in acetonitrile solvent. We discuss the influence of electrolyte concentration, chemical structure of the ionic salt, temperature, conducting versus semiconducting nature of the electrode, electrode geometry and surface roughness on the electric double layer structure and capacitance and compare these properties with those obtained for pure room temperature ionic liquids. We show that electrolytes consisting of solutions of ions can behave quite differently from pure ionic liquid electrolytes.
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Affiliation(s)
- Jenel Vatamanu
- University of Utah, MSE Department, Salt Lake City, UT 84112, USA
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Dhungana KB, Faria LFO, Wu B, Liang M, Ribeiro MCC, Margulis CJ, Castner EW. Structure of cyano-anion ionic liquids: X-ray scattering and simulations. J Chem Phys 2016; 145:024503. [DOI: 10.1063/1.4955186] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Kamal B. Dhungana
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA
| | - Luiz F. O. Faria
- Laboratório de Espectroscopia Molecular, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP, Brazil
| | - Boning Wu
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Min Liang
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Mauro C. C. Ribeiro
- Laboratório de Espectroscopia Molecular, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP, Brazil
| | | | - Edward W. Castner
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
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36
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Haskins JB, Wu JJ, Lawson JW. Computational and Experimental Study of Li-Doped Ionic Liquids at Electrified Interfaces. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2016; 120:11993-12011. [PMID: 33005284 PMCID: PMC7526643 DOI: 10.1021/acs.jpcc.6b02449] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We evaluate the influence of Li-salt doping on the dynamics, capacitance, and structure of three ionic liquid electrolytes, [pyr14][TFSI], [pyr13][FSI], and [EMIM][BF4], using molecular dynamics and polarizable force fields. In this respect, our focus is on the properties of the electric double layer (EDL) formed by the electrolytes at the electrode surface as a function of surface potential (Ψ). The rates of EDL formation are found to be on the order of hundreds of picoseconds and only slightly influenced by the addition of Li-salt. The EDLs of three electrolytes are shown to have different energy storage capacities, which we relate to the EDL formation free energy. The differential capacitance obtained from our computations exhibits asymmetry about the potential of zero charge and is consistent with the camel-like profiles noted from mean field theories and experiments on metallic electrodes. The introduction of Li-salt reduces the noted asymmetry in the differential capacitance profile. Complementary experimental capacitance measurements have been made on our three electrolytes in their neat forms and with Li-salt. The measurements, performed on glassy carbon electrodes, produce U-like profiles, and Li-salt doping is shown to strongly affect capacitance at high magnitudes of Ψ. Differences in the theoretical and experimental shapes and magnitudes of capacitance are rationalized in terms of the electrode surface and pseudocapacitive effects. In both neat and Li-doped liquids, the details of the computational capacitance profile are well described by Ψ-induced changes in the density and molecular orientation of ions in the molecular layer closest to the electrode. Our results suggest that the addition of Li+ induces disorder in the EDL, which originates from the strong binding of anions to Li+. An in-depth analysis of the distribution of Li+ in the EDL reveals that it does not readily enter the molecular layer at the electrode surface, preferring instead to be localized farther away from the surface in the second molecular layer. This behavior is validated through an analysis of the free energy of Li+ solvation as a function of distance from the electrode. Free energy wells are found to coincide with localized concentrations of Li+, the depths of which increase with Ψ and suggest a source of impedance for Li+ to reach the electrode. Finally, we make predictions of the specific energy at ideal graphite utilizing the computed capacitance and previously derived electrochemical windows of the liquids.
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Affiliation(s)
- Justin B. Haskins
- AMA Inc., Thermal Materials Protection Branch, NASA Ames Research Center, Moffett Field, California 94035, USA
| | - James J. Wu
- Photovoltaic and Electrochemical Systems Branch, NASA Glenn Research Center, Cleveland, Ohio 44135, USA
| | - John W. Lawson
- Thermal Materials Protection Branch, NASA Ames Research Center, Moffett Field, California 94035, USA
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37
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In situ scanning tunneling microscopy (STM), atomic force microscopy (AFM) and quartz crystal microbalance (EQCM) studies of the electrochemical deposition of tantalum in two different ionic liquids with the 1-butyl-1-methylpyrrolidinium cation. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2015.07.178] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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38
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Liu Z, Cui T, Pulletikurthi G, Lahiri A, Carstens T, Olschewski M, Endres F. Dendrite-Free Nanocrystalline Zinc Electrodeposition from an Ionic Liquid Containing Nickel Triflate for Rechargeable Zn-Based Batteries. Angew Chem Int Ed Engl 2016; 55:2889-93. [DOI: 10.1002/anie.201509364] [Citation(s) in RCA: 172] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Zhen Liu
- Institute of Electrochemistry; Clausthal University of Technology, Arnold-Sommerfeld-Strasse 6; Clausthal-Zellerfeld 38678 Germany
| | - Tong Cui
- Institute of Electrochemistry; Clausthal University of Technology, Arnold-Sommerfeld-Strasse 6; Clausthal-Zellerfeld 38678 Germany
| | - Giridhar Pulletikurthi
- Institute of Electrochemistry; Clausthal University of Technology, Arnold-Sommerfeld-Strasse 6; Clausthal-Zellerfeld 38678 Germany
| | - Abhishek Lahiri
- Institute of Electrochemistry; Clausthal University of Technology, Arnold-Sommerfeld-Strasse 6; Clausthal-Zellerfeld 38678 Germany
| | - Timo Carstens
- Institute of Electrochemistry; Clausthal University of Technology, Arnold-Sommerfeld-Strasse 6; Clausthal-Zellerfeld 38678 Germany
| | - Mark Olschewski
- Institute of Electrochemistry; Clausthal University of Technology, Arnold-Sommerfeld-Strasse 6; Clausthal-Zellerfeld 38678 Germany
| | - Frank Endres
- Institute of Electrochemistry; Clausthal University of Technology, Arnold-Sommerfeld-Strasse 6; Clausthal-Zellerfeld 38678 Germany
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39
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Liu Z, Cui T, Pulletikurthi G, Lahiri A, Carstens T, Olschewski M, Endres F. Dendritenfreie elektrochemische Abscheidung von nanokristallinem Zink aus einer Nickeltriflat-haltigen ionischen Flüssigkeit für wiederaufladbare Zn-Batterien. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201509364] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zhen Liu
- Institut für Elektrochemie; Technische Universität Clausthal; Arnold-Sommerfeld-Straße 6 38678 Clausthal-Zellerfeld Deutschland
| | - Tong Cui
- Institut für Elektrochemie; Technische Universität Clausthal; Arnold-Sommerfeld-Straße 6 38678 Clausthal-Zellerfeld Deutschland
| | - Giridhar Pulletikurthi
- Institut für Elektrochemie; Technische Universität Clausthal; Arnold-Sommerfeld-Straße 6 38678 Clausthal-Zellerfeld Deutschland
| | - Abhishek Lahiri
- Institut für Elektrochemie; Technische Universität Clausthal; Arnold-Sommerfeld-Straße 6 38678 Clausthal-Zellerfeld Deutschland
| | - Timo Carstens
- Institut für Elektrochemie; Technische Universität Clausthal; Arnold-Sommerfeld-Straße 6 38678 Clausthal-Zellerfeld Deutschland
| | - Mark Olschewski
- Institut für Elektrochemie; Technische Universität Clausthal; Arnold-Sommerfeld-Straße 6 38678 Clausthal-Zellerfeld Deutschland
| | - Frank Endres
- Institut für Elektrochemie; Technische Universität Clausthal; Arnold-Sommerfeld-Straße 6 38678 Clausthal-Zellerfeld Deutschland
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40
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McDonald S, Elbourne A, Warr GG, Atkin R. Metal ion adsorption at the ionic liquid-mica interface. NANOSCALE 2016; 8:906-914. [PMID: 26661934 DOI: 10.1039/c5nr05833c] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Mica has been employed in many studies of ionic liquid (IL) interfaces on account of its atomic smoothness and well defined surface properties. However, until now it has been unclear whether ions dissolved in ILs can compete with the IL cation and adsorb to mica charge sites. In this work amplitude modulated atomic force microscopy (AM-AFM) has been used to probe metal ion adsorption at the interface of mica with propylammonium nitrate (PAN), a room temperature IL. Lithium, sodium, potassium, magnesium and calcium nitrate salts were added to PAN at a concentration of ∼60 mM. Aluminum nitrate was also investigated, but only at 5 mM because its solubility in PAN is much lower. The AM-AFM images obtained when the metal ions were present are strikingly different to that of pure PAN, indicating that the ions compete effectively with the propylammonium cation and adsorb to negatively charged sites on the mica surface despite their much lower concentration. This is a consequence of electrostatic attractions between the mica charge sites and the metal ions being significantly stronger than for the propylammonium cation; compared to the metal ions the propylammonium charged group is relatively constrained sterically. A distinct honeycomb pattern is noted for the PAN + Al(3+) system, less obviously for the divalent ions and not at all for monovalent ions. This difference is attributed to the strength of electrostatic interactions between metal ions and mica charge sites increasing with the ion charge, which means that divalent and (particularly) trivalent ions are located more precisely above the charged sites of the mica lattice. The images obtained allow important distinctions between metal ion adsorption at mica-water and mica-PAN interfaces to be made.
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Affiliation(s)
- Samila McDonald
- Discipline of Chemistry, The Newcastle Institute for Energy and Resources, The University of Newcastle, Newcastle, NSW, Australia.
| | - Aaron Elbourne
- Discipline of Chemistry, The Newcastle Institute for Energy and Resources, The University of Newcastle, Newcastle, NSW, Australia.
| | - Gregory G Warr
- School of Chemistry, University of Sydney, Sydney, NSW, Australia
| | - Rob Atkin
- Discipline of Chemistry, The Newcastle Institute for Energy and Resources, The University of Newcastle, Newcastle, NSW, Australia.
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41
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Müller C, Németh K, Vesztergom S, Pajkossy T, Jacob T. The interface between HOPG and 1-butyl-3-methyl-imidazolium hexafluorophosphate. Phys Chem Chem Phys 2016; 18:916-25. [DOI: 10.1039/c5cp05406k] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The interface between highly oriented pyrolytic graphite (HOPG) and 1-butyl-3-metyl-imidazolium hexafluorophosphate (BMIPF6) has been studied using cyclic voltammetry, electrochemical impedance spectroscopy, immersion charge measurements and in situ scanning tunneling microscopy (in situ STM).
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Affiliation(s)
- C. Müller
- Institute of Electrochemistry
- Ulm University
- Albert-Einstein-Allee 47
- Ulm D-89069
- Germany
| | - K. Németh
- Institute for Solid State Physics and Optics
- Wigner Research Centre for Physics
- Hungarian Academy of Sciences
- H–1121 Budapest
- Hungary
| | | | - T. Pajkossy
- Institute of Materials and Environmental Chemistry
- Research Centre for Natural Sciences
- Hungarian Academy of Sciences
- H-1117 Budapest
- Hungary
| | - T. Jacob
- Institute of Electrochemistry
- Ulm University
- Albert-Einstein-Allee 47
- Ulm D-89069
- Germany
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42
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Begić S, Li H, Atkin R, Hollenkamp AF, Howlett PC. A comparative AFM study of the interfacial nanostructure in imidazolium or pyrrolidinium ionic liquid electrolytes for zinc electrochemical systems. Phys Chem Chem Phys 2016; 18:29337-29347. [DOI: 10.1039/c6cp04299f] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
AFM measurements show that the electrochemical performance of zinc based ionic liquid electrolytes is controlled by ion arrangements at the electrode surface.
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Affiliation(s)
- Srđan Begić
- ARC Centre of Excellence for Electromaterials Science (ACES)
- Institute for Frontier Materials (IFM)
- Deakin University Burwood Campus
- Burwood
- Australia
| | - Hua Li
- Priority Research Centre for Advanced Fluids and Interfaces
- The University of Newcastle
- Callaghan
- Australia
| | - Rob Atkin
- Priority Research Centre for Advanced Fluids and Interfaces
- The University of Newcastle
- Callaghan
- Australia
| | | | - Patrick C. Howlett
- ARC Centre of Excellence for Electromaterials Science (ACES)
- Institute for Frontier Materials (IFM)
- Deakin University Burwood Campus
- Burwood
- Australia
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43
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Kamijo T, Arafune H, Morinaga T, Honma S, Sato T, Hino M, Mizukami M, Kurihara K. Lubrication Properties of Ammonium-Based Ionic Liquids Confined between Silica Surfaces Using Resonance Shear Measurements. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:13265-13270. [PMID: 26602172 DOI: 10.1021/acs.langmuir.5b03354] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
To evaluate the friction properties of new lubrication systems, two types of ammonium-based ionic liquids (ILs), N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate ([DEME][BF4]) and N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis(trifluoromethanesulfonyl) imide ([DEME][TFSI]), were investigated by resonance shear measurements (RSM) and reciprocating type tribotests between silica (glass) surfaces. RSM revealed that an IL layer of ca. 2 nm in thickness was maintained between the silica surfaces under an applied load of 0.40 mN ∼ 1.2 mN. The relative intensity of the RMS signal indicated that the friction of the system was lower for [DEME][BF4], 0.12, than that of [DEME][TFSI], 0.18. On the other hand, the friction coefficients μk obtained from the tribotests of [DEME][BF4] were lower than that of [DEME][TFSI] for sliding velocities in the range of 5.0 × 10(-4) m s(-1) to 3.0 × 10(-2) m s(-1) under applied loads of 196-980 mN. The friction coefficients obtained by the tribotest are discussed with reference to the RSM results.
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Affiliation(s)
- Toshio Kamijo
- Department of Creative Engineering, National Institute of Technology, Tsuruoka College , Sawada, Inooka, Tsuruoka, 997-8511, Japan
| | - Hiroyuki Arafune
- Department of Creative Engineering, National Institute of Technology, Tsuruoka College , Sawada, Inooka, Tsuruoka, 997-8511, Japan
| | - Takashi Morinaga
- Department of Creative Engineering, National Institute of Technology, Tsuruoka College , Sawada, Inooka, Tsuruoka, 997-8511, Japan
| | - Saika Honma
- Department of Creative Engineering, National Institute of Technology, Tsuruoka College , Sawada, Inooka, Tsuruoka, 997-8511, Japan
| | - Takaya Sato
- Department of Creative Engineering, National Institute of Technology, Tsuruoka College , Sawada, Inooka, Tsuruoka, 997-8511, Japan
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44
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Smith AM, Perkin S. Influence of Lithium Solutes on Double-Layer Structure of Ionic Liquids. J Phys Chem Lett 2015; 6:4857-4861. [PMID: 26580815 DOI: 10.1021/acs.jpclett.5b02166] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The ionic liquid-electrode interface has attracted much recent interest owing to its importance for development of energy storage devices; however, the important step of adding electro-active ions is not yet well understood at the molecular level. Using direct force measurements across confined electrolyte films, we study the effect of added lithium-ion solute on the double-layer structure of an ionic liquid electrolyte with molecular resolution. We find anionic clusters involving lithium can persist adjacent to the surfaces, and in many cases, this inhibits direct adsorption of lithium ions to the negative surface. Two apparently similar ionic liquid solvents show diverging properties, with one facilitating and the other preventing direct Li-ion adsorption onto the negative surface. The results have implications for the selection of ionic liquids as electrolytes in lithium-ion batteries.
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Affiliation(s)
- Alexander M Smith
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Susan Perkin
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom
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45
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Abstract
Capacitive energy storage devices are receiving increasing experimental and theoretical attention due to their enormous potential for energy applications. Current research in this field is focused on the improvement of both the energy and the power density of supercapacitors by optimizing the nanostructure of porous electrodes and the chemical structure/composition of the electrolytes. However, the understanding of the underlying correlations and the mechanisms of electric double layer formation near charged surfaces and inside nanoporous electrodes is complicated by the complex interplay of several molecular scale phenomena. This Perspective presents several aspects regarding the experimental and theoretical research in the field, discusses the current atomistic and molecular scale understanding of the mechanisms of energy and charge storage, and provides a brief outlook to the future developments and applications of these devices.
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Affiliation(s)
- Jenel Vatamanu
- Department of Materials Science & Engineering, The University of Utah , 122 S. Central Campus Drive, Salt Lake City, Utah 84112, United States
| | - Dmitry Bedrov
- Department of Materials Science & Engineering, The University of Utah , 122 S. Central Campus Drive, Salt Lake City, Utah 84112, United States
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46
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Dold C, Amann T, Kailer A. Influence of electric potentials on friction of sliding contacts lubricated by an ionic liquid. Phys Chem Chem Phys 2015; 17:10339-42. [PMID: 25805119 DOI: 10.1039/c4cp05965d] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Tribological investigations on the macroscopic scale revealed that friction can be influenced in situ by applying electric potentials, if electrically conductive fluid such as an ionic liquid is used as a lubricant. Enrichment of charged ions at a steel interface occurs by applying electric surface potentials in a three-electrode setup. As a consequence, the lubrication conditions change. It is supposed that electrically influenced surface adsorption and electrokinetic effects are the main mechanisms by which friction is varied.
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Affiliation(s)
- Christian Dold
- Fraunhofer Institute for Mechanics of Materials IWM, Woehlerstrasse. 11, 79108 Freiburg, Germany.
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Sakai K, Okada K, Uka A, Misono T, Endo T, Sasaki S, Abe M, Sakai H. Effects of Water on Solvation Layers of Imidazolium-Type Room Temperature Ionic Liquids on Silica and Mica. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:6085-6091. [PMID: 25996798 DOI: 10.1021/acs.langmuir.5b01184] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Effects of the addition of water on solvation layers of imidazolium-type room temperature ionic liquids (RT-ILs) have been studied through force curve measurements of atomic force microscopy (AFM). Two kinds of RT-ILs were employed in this study; one is a hydrophilic RT-IL (1-butyl-3-methylimidazolium tetrafluoroborate, BmimBF4), and the other is a hydrophobic one (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, EmimTFSI). These RT-ILs form solvation layers on hydrophilic solid substances (i.e., silica and mica) in the absence of added water. The addition of water into BmimBF4 resulted in the disruption of the solvation layers and then the formation of an interfacial water phase on silica. In contrast, the formation of the interfacial water phase was not evidenced on mica because of the absence of hydrogen-bonding sites on the mica surface. Interestingly, the addition of water into EmimTFSI induced the formation of the interfacial water phase on the two solid surfaces. In the EmimTFSI system, importantly, significantly greater adhesion forces were observed on silica than on mica. This reflects the different formation mechanisms of the interfacial water phase on the two solid surfaces. We conclude that the hydrogen bonding is a key factor in determining whether water molecules can be adsorbed on the solid surfaces, but it is also necessary to take into account the hydrophilic/hydrophobic nature of the RT-ILs.
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Affiliation(s)
| | | | | | | | | | - Shinya Sasaki
- §Department of Mechanical Engineering, Faculty of Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585, Japan
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Affiliation(s)
- Robert Hayes
- Discipline
of Chemistry, The University of Newcastle, NSW 2308, Callaghan, Australia
| | - Gregory G. Warr
- School
of Chemistry, The University of Sydney, NSW 2006, Sydney, Australia
| | - Rob Atkin
- Discipline
of Chemistry, The University of Newcastle, NSW 2308, Callaghan, Australia
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Ichii T, Furutani Y, Negami M, Utsunomiya T, Murase K, Sugimura H. True Molecular-resolution Imaging on Alkanethiol Self-assembled Monolayers in Ionic Liquids by Frequency Modulation Atomic Force Microscopy Utilizing a Quartz Tuning Fork Sensor. CHEM LETT 2015. [DOI: 10.1246/cl.141107] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Takashi Ichii
- Department of Materials Science and Engineering, Kyoto University
| | | | - Masahiro Negami
- Department of Materials Science and Engineering, Kyoto University
| | - Toru Utsunomiya
- Department of Materials Science and Engineering, Kyoto University
| | - Kuniaki Murase
- Department of Materials Science and Engineering, Kyoto University
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50
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Ludwig T, Guo L, McCrary P, Zhang Z, Gordon H, Quan H, Stanton M, Frazier RM, Rogers RD, Wang HT, Turner CH. Mechanism of bismuth telluride exfoliation in an ionic liquid solvent. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3644-3652. [PMID: 25760309 DOI: 10.1021/acs.langmuir.5b00239] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Bismuth telluride (Bi2Te3) is a well-known thermoelectric material that has a layered crystal structure. Exfoliating Bi2Te3 to produce two-dimensional (2D) nanosheets is extremely important because the exfoliated nanosheets possess unique properties, which can potentially revolutionize several material technologies such as thermoelectrics, heterogeneous catalysts, and infrared detectors. In this work, ionic liquid (IL) 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) is used to exfoliate Bi2Te3 nanoplatelets. In both experiments and in molecular dynamics (MD) simulations, the Bi2Te3 nanoplatelets yield a stable dispersion of 2D nanosheets in the IL solvent, and our MD simulations provide molecular-level insight into the kinetics and thermodynamics of the exfoliation process. An analysis of the dynamics of Bi2Te3 during exfoliation indicates that the relative translation (sliding apart) of adjacent layers caused by IL-induced forces plays an important role in the process. Moreover, an evaluation of the MD trajectories and electrostatic interactions indicates that the [C4mim](+) cation is primarily responsible for initiating Bi2Te3 layer sliding and separation, while the Cl(-) anion is less active. Overall, our combined experimental and computational investigation highlights the effectiveness of IL-assisted exfoliation, and the underlying molecular-level insights should accelerate the development of future exfoliation techniques for producing 2D chalcogenide materials.
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Affiliation(s)
| | | | | | | | - Haley Gordon
- ⊥Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
- #St. Mary's College, Notre Dame, Indiana 46556, United States
| | | | - Michael Stanton
- ∇Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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