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Huang J, Chen Y, Eikerling M. Correlated surface-charging behaviors of two electrodes in an electrochemical cell. Proc Natl Acad Sci U S A 2023; 120:e2307307120. [PMID: 37579163 PMCID: PMC10450406 DOI: 10.1073/pnas.2307307120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/06/2023] [Indexed: 08/16/2023] Open
Abstract
It is revealed herein that surface-charging behaviors of the two electrodes constituting an electrochemical cell cannot be described independently by their respective electric double-layer (EDL) properties. Instead, they are correlated in such a way that the surface-charging behavior of each electrode is determined by the EDL and the reaction kinetics at both electrodes. Two fundamental equations describing the correlated surface-charging behaviors are derived, and approximate analytical solutions are obtained at low and high current densities, respectively, to facilitate transparent understanding. Important implications of the presented conceptual analysis for theoretical and computational electrochemistry are discussed. A strategy of modulating the activity of one electrode by tuning EDL parameters of the other in a two-electrode electrochemical cell is demonstrated.
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Affiliation(s)
- Jun Huang
- Institute of Energy and Climate Research, IEK-13: Theory and Computation of Energy Materials, Forschungszentrum Jülich GmbH, 52425Jülich, Germany
- Theory of Electrocatalytic Interfaces, Faculty of Georesources and Materials Engineering, Rheinisch-Westfälische Technische Hochschule Aachen University, 52062Aachen, Germany
| | - Yanxia Chen
- Hefei National Research Center for Physical Science at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei230026, China
| | - Michael Eikerling
- Institute of Energy and Climate Research, IEK-13: Theory and Computation of Energy Materials, Forschungszentrum Jülich GmbH, 52425Jülich, Germany
- Chair of Theory and Computation of Energy Materials, Faculty of Georesources and Materials Engineering, RWTH Aachen University, 52062Aachen, Germany
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Sheyfer D, Mariano RG, Kawaguchi T, Cha W, Harder RJ, Kanan MW, Hruszkewycz SO, You H, Highland MJ. Operando Nanoscale Imaging of Electrochemically Induced Strain in a Locally Polarized Pt Grain. Nano Lett 2023; 23:1-7. [PMID: 36541700 DOI: 10.1021/acs.nanolett.2c01015] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Developing new methods that reveal the structure of electrode materials under polarization is key to constructing robust structure-property relationships. However, many existing methods lack the spatial resolution in structural changes and fidelity to electrochemical operating conditions that are needed to probe catalytically relevant structures. Here, we combine a nanopipette electrochemical cell with three-dimensional X-ray Bragg coherent diffractive imaging to study how strain in a single Pt grain evolves in response to applied potential. During polarization, marked changes in surface strain arise from the Coulombic attraction between the surface charge on the electrode and the electrolyte ions in the electrochemical double layers, while the strain in the bulk of the crystal remains unchanged. The concurrent surface redox reactions have a strong influence on the magnitude and nature of the strain changes under polarization. Our studies provide a powerful blueprint to understand how structural evolution influences electrochemical performance at the nanoscale.
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Affiliation(s)
- Dina Sheyfer
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois60439, United States
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois60439, United States
| | - Ruperto G Mariano
- Department of Chemistry, Stanford University, Stanford, California94305, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts02141, United States
| | - Tomoya Kawaguchi
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois60439, United States
- Institute for Materials Research, Tohoku University, Sendai, 9808577, Japan
| | - Wonsuk Cha
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois60439, United States
| | - Ross J Harder
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois60439, United States
| | - Matthew W Kanan
- Department of Chemistry, Stanford University, Stanford, California94305, United States
| | - Stephan O Hruszkewycz
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois60439, United States
| | - Hoydoo You
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois60439, United States
| | - Matthew J Highland
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois60439, United States
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Michaels H, Freitag M. Assessment of TiO 2 Blocking Layers for Cu II/I-Electrolyte Dye-Sensitized Solar Cells by Electrochemical Impedance Spectroscopy. ACS Appl Energy Mater 2022; 5:1933-1941. [PMID: 35572067 PMCID: PMC9096799 DOI: 10.1021/acsaem.1c03433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 02/03/2022] [Indexed: 06/15/2023]
Abstract
The TiO2 blocking layer in dye-sensitized solar cells is the most difficult component to evaluate at thicknesses below 50 nm, but it is crucial for the power conversion efficiency. Here, the electrode capacitance of TiO2 blocking layers is tested in aqueous [Fe(CN)6]3-/4- and correlated to the performance of photoanodes in devices based on a [Cu(tmby)2]2+/+ electrolyte. The effects of the blocking layer on electronic recombination in the devices are illustrated with transient photovoltage methods and electrochemical impedance analysis. We have thus demonstrated a feasible and facile method to assess TiO2 blocking layers for the fabrication of dye-sensitized solar cells.
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Affiliation(s)
- Hannes Michaels
- Department
of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 75120, Sweden
- School
of Natural and Environmental Science, Newcastle
University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Marina Freitag
- Department
of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 75120, Sweden
- School
of Natural and Environmental Science, Newcastle
University, Newcastle upon Tyne NE1 7RU, United Kingdom
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De Silva T, Damery C, Alkhaldi R, Karunanithy R, Gallaba DH, Patil PD, Wasala M, Sivakumar P, Migone A, Talapatra S. Carbon Nanotube Based Robust and Flexible Solid-State Supercapacitor. ACS Appl Mater Interfaces 2021; 13:56004-56013. [PMID: 34792349 DOI: 10.1021/acsami.1c12551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
All solid-state flexible electrochemical double-layer capacitors (EDLCs) are crucial for providing energy options in a variety of applications, ranging from wearable electronics to bendable micro/nanotechnology. Here, we report on the development of robust EDLCs using aligned multiwalled carbon nanotubes (MWCNTs) grown directly on thin metal foils embedded in a poly(vinyl alcohol)/phosphoric acid (PVA/H3PO4) polymer gel. The thin metal substrate holding the aligned MWCNT assembly provides mechanical robustness and the PVA/H3PO4 polymer gel, functioning both as the electrolyte as well as the separator, provides sufficient structural flexibility, without any loss of charge storage capacity under flexed conditions. The performance stability of these devices was verified by testing them under straight and bent formations. A high value of the areal specific capacitance (CSP) of ∼14.5 mF cm-2 with an energy density of ∼1 μW h cm-2 can be obtained in these devices. These values are significantly higher (in some cases, orders of magnitude) than several graphene as well as single-walled nanotube-based EDLC's utilizing similar electrolytes. We further show that these devices can withstand multiple (∼2500) mechanical bending cycles, without losing their energy storage capacities and are functional within the temperature range of 20 to 70 °C. Several strategies for enhancing the capacitive charge storage, such as physically stacking (in parallel) individual devices, or postproduction thermal annealing of electrodes, are also demonstrated. These findings demonstrated in this article provide tremendous impetus toward the realization of robust, stackable, and flexible all solid-state supercapacitors.
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Affiliation(s)
- Thushani De Silva
- Department of Physics, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Cole Damery
- Department of Physics, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Rana Alkhaldi
- Department of Physics, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Robinson Karunanithy
- Department of Physics, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Dinuka H Gallaba
- Department of Physics, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Prasanna D Patil
- Department of Physics, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Milinda Wasala
- Department of Physics, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Poopalasingam Sivakumar
- Department of Physics, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Aldo Migone
- Department of Physics, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Saikat Talapatra
- Department of Physics, Southern Illinois University, Carbondale, Illinois 62901, United States
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Cheng C, Weissmüller J, Ngan AHW. Fast and Reversible Actuation of Metallic Muscles Composed of Nickel Nanowire-Forest. Adv Mater 2016; 28:5315-5321. [PMID: 27146431 DOI: 10.1002/adma.201600286] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 02/26/2016] [Indexed: 06/05/2023]
Abstract
Surface-charge-induced reversible and millimeter-scale deflection is found in a bilayered Ni cantilever upon cyclic potential triggering. The nanowire-forest structure, in which unidirectional primary nanowires are evenly separated by cross-linking subnanowires, ensures fast ion transport leading to a record-high strain response time ≈0.1 s. The actuation is sustainable beyond 800 cycles; the strain energy is compatible with human skeletal muscles.
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Affiliation(s)
- Chuan Cheng
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, P. R. China
- Institut für Werkstoffphysik und Werkstofftechnologie, Technische Universität Hamburg-Harburg, 21073, Hamburg, Germany
| | - Jörg Weissmüller
- Institut für Werkstoffphysik und Werkstofftechnologie, Technische Universität Hamburg-Harburg, 21073, Hamburg, Germany
| | - Alfonso H W Ngan
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, P. R. China
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Cheng C, Ngan AHW. Reversible electrochemical actuation of metallic nanohoneycombs induced by pseudocapacitive redox processes. ACS Nano 2015; 9:3984-3995. [PMID: 25758028 DOI: 10.1021/nn507466n] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Current metallic-based electrochemical actuators are limited to nanoporous gold/platinum with randomly distributed pores, where the charge-induced reversible strain is mainly due to the nonfaradic charging/discharging processes along the capacitive electrochemical double layer. Here, we report an electrochemical actuating property of nanohoneycomb-structured nickel, with the actuation mechanism mainly due to a pseudocapacitive behavior by means of reversible faradic redox reactions. By using a dual-template synthesis method, a bilayered cantilever, comprising a nanohoneycomb layer backed by a solid layer of the same metal, was fabricated. Reversible bending of the cantilever upon cyclic potential triggering was observed. The strain of the cantilever increases nonlinearly with both potential and charge due to redox reactions. The maximum strain that can be achieved under a certain scan rate complies with a linear relationship with the capacity. Benefiting from the stable Ni(II)/Ni(III) redox couples at the electrode surface, the reversible actuation is very stable in hydroxide solutions.
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Affiliation(s)
- Chuan Cheng
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Alfonso H W Ngan
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
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