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Schulz A, Lunkenheimer P, Loidl A. Ionic Conductivity of a Lithium-Doped Deep Eutectic Solvent: Glass Formation and Rotation-Translation Coupling. J Phys Chem B 2024; 128:3454-3462. [PMID: 38564781 DOI: 10.1021/acs.jpcb.4c00412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Deep eutectic solvents with admixed lithium salts are considered as electrolytes in electrochemical devices, such as batteries or supercapacitors. Compared to eutectic mixtures of hydrogen-bond donors and lithium salts, their raw-material costs are significantly lower. Not much is known about glassy freezing and rotational-translation coupling of such systems. Here, we investigate these phenomena by applying dielectric spectroscopy to the widely studied deep eutectic solvent glyceline, to which 1 and 5 mol % LiCl were added. Our study covers a wide temperature range, including a deeply supercooled state. The temperature dependences of the detected dipolar reorientation dynamics and ionic direct current (dc) conductivity reveal the signatures of glassy freezing. In comparison to pure glyceline, the lithium admixture leads to a reduction of ionic conductivity, which is accompanied by a reduction of the rotational dipolar mobility. However, this reduction is much smaller than that for deep eutectic solvents (DESs), where one main component is lithium salt, which we trace back to the lower glass-transition temperatures of lithium-doped DESs. In contrast to pure glyceline, the ionic and dipolar dynamics become increasingly decoupled at low temperatures and obey a fractional Debye-Stokes-Einstein relation, as previously found in other glass-forming liquids. The obtained results demonstrate the relevance of decoupling effects and glass transition to the enhancement of the technically relevant ionic conductivity in such lithium-doped DESs.
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Affiliation(s)
- A Schulz
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - P Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - A Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
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2
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Tohamy HAS, Elnasharty MMM, Abdel-Aziz MS, El-Sakhawy M, Turky G, Kamel S. Antibacterial activity and dielectric properties of the PVA/cellulose nanocrystal composite using the synergistic effect of rGO@CuNPs. Int J Biol Macromol 2024; 261:129801. [PMID: 38309410 DOI: 10.1016/j.ijbiomac.2024.129801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/05/2024]
Abstract
This work aims to enhance the performance of the polyvinyl alcohol (PVA) composite by using cellulose nanocrystal (CNC) as reinforcement and copper nanoparticles (CuNPs)/reduced graphene oxide (rGO) as conducting and antimicrobial reagents. Firstly, rGO was loaded onto CuNPs using an eco-friendly microwave method. Different techniques characterized the components and prepared composites, which indicated the incorporation of cellulose nanocrystals and rGO@CuNPs within the polyvinyl alcohol matrix. Utilizing the clear zone of inhibition, the antibacterial test was quantified. Compared to the neat composite, the rGO@CuNPs loaded polyvinyl alcohol/ cellulose nanocrystal composites exhibited no bacterial growth against S. aureus, E. coli, and C. albicans. However, all composites did not have antifungal activity against A. niger. The combination of conductivity and interfacial polarization is the reason for the abrupt increase of permittivity with decreasing frequency. Besides, adding rGO@CuNPs improved the electrical conductivity. DC-Conductivity increased about a decade after adding cellulose nanocrystal to polyvinyl alcohol, then another decade after adding CuONPs. The electric loss modulus representation shows a systematic shift in the peak position towards higher frequencies, decreasing the so-called conductivity relaxation time. This is the main reason for the enhancement of conductivity. The systematic attenuation of peaks' height with increasing conductivity is still unclear.
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Affiliation(s)
- Hebat-Allah S Tohamy
- Cellulose and Paper Department, National Research Centre, 33 El Bohouth Str., PO 12622, Dokki, Giza, Egypt
| | | | - Mohamed S Abdel-Aziz
- Microbial Chemistry Department, National Research Centre, 33 El Bohouth st. (former El tahrir st.), P.O. 12622, Dokki, Giza, Egypt
| | - Mohamed El-Sakhawy
- Cellulose and Paper Department, National Research Centre, 33 El Bohouth Str., PO 12622, Dokki, Giza, Egypt
| | - Gamal Turky
- Microwave Physics and Dielectrics Department, National Research Centre, 12622, Egypt.
| | - Samir Kamel
- Cellulose and Paper Department, National Research Centre, 33 El Bohouth Str., PO 12622, Dokki, Giza, Egypt
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3
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Lansab S, Schwan T, Moch K, Böhmer R. Shear rheology senses the electrical room-temperature conductivity optimum in highly Li doped dinitrile electrolytes. J Chem Phys 2024; 160:084503. [PMID: 38411232 DOI: 10.1063/5.0186008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/28/2024] [Indexed: 02/28/2024] Open
Abstract
Glutaronitrile (GN) doped with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) at concentrations below and above the room-temperature conductivity optimum near 1M of Li salt is investigated using dielectric spectroscopy and shear rheology. The experiments are carried out from ambient down to the glass transition temperature Tg, which increases considerably as LiTFSI is admixed to GN. As the temperature is lowered, the conductivity optimum shifts to lower salt concentrations, while the power-law exponents connecting resistivity and molecular reorientation time remain smallest for the 1M composition. By contrast, the rheologically detected time constants, as well as those obtained using dielectric spectroscopy, increase monotonically with increasing Li salt concentration for all temperatures. It is demonstrated that the shear mechanical measurements are, nevertheless, sensitive to the 1M conductivity optimum, thus elucidating the interplay of the dinitrile matrix with the mobile species. The data for the Li doped GN and other nitrile solvents all follow about the same Walden line, in harmony with their highly conductive character. The composition dependent relation between the ionic and the reorientational dynamics is also elucidated.
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Affiliation(s)
- Sofiane Lansab
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Tobias Schwan
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Kevin Moch
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Roland Böhmer
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
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4
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Schulz A, Lunkenheimer P, Loidl A. Rotational dynamics, ionic conductivity, and glass formation in a ZnCl2-based deep eutectic solvent. J Chem Phys 2024; 160:054502. [PMID: 38341686 DOI: 10.1063/5.0187729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/15/2024] [Indexed: 02/13/2024] Open
Abstract
Glass formation and reorientational motions are widespread but often-neglected features of deep eutectic solvents although both can be relevant for the technically important ionic conductivity at room temperature. Here, we investigate these properties for two mixtures of ethylene glycol and ZnCl2, which were recently considered superior electrolyte materials for application in zinc-ion batteries. For this purpose, we employed dielectric spectroscopy performed in a broad temperature range, extending from the supercooled state at low temperatures up to the liquid phase around room temperature and beyond. We find evidence for a relaxation process arising from dipolar reorientation dynamics, which reveals the clear signatures of glassy freezing. This freezing also governs the temperature dependence of the ionic dc conductivity. We compare the obtained results with those for deep eutectic solvents that are formed by the same hydrogen-bond donor, ethylene glycol, but by two different salts, choline chloride and lithium triflate. The four materials reveal significantly different ionic and reorientational dynamics. Moreover, we find varying degrees of decoupling of rotational dipolar and translational ionic motions, which can partly be described by a fractional Debye-Stokes-Einstein relation. The typical glass-forming properties of these solvents strongly affect their room-temperature conductivity.
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Affiliation(s)
- A Schulz
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - P Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - A Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
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5
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Lunkenheimer P, Loidl A, Johari GP. Dipolar relaxation, conductivity, and polar order in AgCN. J Chem Phys 2023; 158:2889003. [PMID: 37154277 DOI: 10.1063/5.0148873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/24/2023] [Indexed: 05/10/2023] Open
Abstract
By using dielectric spectroscopy in a broad range of temperatures and frequencies, we have investigated dipolar relaxations, the dc conductivity, and the possible occurrence of polar order in AgCN. The conductivity contributions dominate the dielectric response at elevated temperatures and low frequencies, most likely arising from the mobility of the small silver ions. In addition, we observe the dipolar relaxation dynamics of the dumbbell-shaped CN- ions, whose temperature dependence follows the Arrhenius behavior with a hindering barrier of 0.59 eV (57 kJ/mol). It correlates well with a systematic development of the relaxation dynamics with the cation radius, previously observed in various alkali cyanides. By comparison with the latter, we conclude that AgCN does not exhibit a plastic high-temperature phase with free rotation of the cyanide ions. Instead, our results indicate that a phase with quadrupolar order, revealing dipolar head-to-tail disorder of the CN- ions, exists at elevated temperatures up to the decomposition temperature, which crosses over to long-range polar order of the CN dipole moments below about 475 K. Dipole ordering was also reported for NaCN and KCN, and a comparison with these systems suggests a critical relaxation rate of 105-107 Hz, marking the onset of dipolar order in the cyanides. The detected relaxation dynamics in this order-disorder type polar state points to glasslike freezing below about 195 K of a fraction of non-ordered CN dipoles.
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Affiliation(s)
- P Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - A Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - G P Johari
- Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7, Canada
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6
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Lansab S, Grabe B, Böhmer R. Paddle-wheel mechanism in doped succinonitrile-glutaronitrile plastic electrolyte: a joint magnetic resonance, dielectric, and viscosimetry study of Li ion translational and molecular reorientational dynamics. Phys Chem Chem Phys 2023; 25:9382-9393. [PMID: 36924457 DOI: 10.1039/d2cp05799a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Mixtures of 60% SN (succinonitrile) and 40% GN (glutaronitrile) doped with LiTFSI or LiPF6 at different concentrations are investigated using dielectric spectroscopy. Room temperature conductivities up to 10-3 S cm-1 are measured along with an overall conductivity enhancement of almost five decades compared to pure SN. Additionally, the dynamics of the methylene (CD2) groups of SN and that of the Li+ ions within the mixture are studied in a wide temperature range using 2H and 7Li NMR relaxometry, respectively. Static-field-gradient proton NMR combined with viscosity measurements probe the molecular diffusion. GN addition and Li doping both enhance the electrical conductivity significantly, while leaving the reorientational motion within the matrix essentially unchanged. The times scales and thus the effective energy barriers characterizing the Li ion motion as well as the molecular reorientations are very similar in the liquid and in the plastic phases, findings that argue in favor of the presence of a paddle-wheel mechanism.
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Affiliation(s)
- S Lansab
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany.
| | - B Grabe
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - R Böhmer
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany.
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7
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Scholz T, Schneider C, Terban MW, Deng Z, Eger R, Etter M, Dinnebier RE, Canepa P, Lotsch BV. Superionic Conduction in the Plastic Crystal Polymorph of Na 4P 2S 6. ACS ENERGY LETTERS 2022; 7:1403-1411. [PMID: 35434367 PMCID: PMC9008513 DOI: 10.1021/acsenergylett.1c02815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
Sodium thiophosphates are promising materials for large-scale energy storage applications benefiting from high ionic conductivities and the geopolitical abundance of the elements. A representative of this class is Na4P2S6, which currently shows two known polymorphs-α and β. This work describes a third polymorph of Na4P2S6, γ, that forms above 580 °C, exhibits fast-ion conduction with low activation energy, and is mechanically soft. Based on high-temperature diffraction, pair distribution function analysis, thermal analysis, impedance spectroscopy, and ab initio molecular dynamics calculations, the γ-Na4P2S6 phase is identified to be a plastic crystal characterized by dynamic orientational disorder of the P2S6 4- anions translationally fixed on a body-centered cubic lattice. The prospect of stabilizing plastic crystals at operating temperatures of solid-state batteries, with benefits from their high ionic conductivities and mechanical properties, could have a strong impact in the field of solid-state battery research.
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Affiliation(s)
- Tanja Scholz
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Christian Schneider
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Maxwell W. Terban
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Zeyu Deng
- Department
of Materials Science and Engineering, National
University of Singapore, 9 Engineering Drive 1, 117575 Singapore
| | - Roland Eger
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Martin Etter
- Deutsches
Elektronensynchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
| | - Robert E. Dinnebier
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Pieremanuele Canepa
- Department
of Materials Science and Engineering, National
University of Singapore, 9 Engineering Drive 1, 117575 Singapore
- Department
of Chemical and Biomolecular Engineering, National University of Singapore, Engineering Drive 4, 117585 Singapore
| | - Bettina V. Lotsch
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
- LMU
Munich, Butenandtstraße
5-13, 81377 Munich, Germany
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8
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How the cation size impacts on the relaxational and diffusional dynamics of supercooled butylammonium-based ionic liquids: DPEBA–TFSI versus BTMA–TFSI. Z PHYS CHEM 2021. [DOI: 10.1515/zpch-2021-3138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Li-bis(trifluoromethylsulfonyl)imide based ionic liquids with either butyl-trimethylammonium or N,N-dimethyl-N-(2-(propionyloxy)-ethyl)butan-1-ammonium as the anion were studied using proton and fluorine relaxometry as well as using field-gradient diffusometry to gain separate access to cation and anion dynamics in these compounds. The transport parameters obtained for these ionic liquids are compared with the estimates based on the conductivity data from literature and from the present work. The impact of cation size on correlation effects, the latter parameterized in terms of various Haven ratios, is mapped out.
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9
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Schulz A, Lunkenheimer P, Loidl A. Lithium-salt-based deep eutectic solvents: Importance of glass formation and rotation-translation coupling for the ionic charge transport. J Chem Phys 2021; 155:044503. [PMID: 34340372 DOI: 10.1063/5.0055493] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Lithium-salt-based deep eutectic solvents, where the only cation is Li+, are promising candidates as electrolytes in electrochemical energy-storage devices, such as batteries. We have performed broadband dielectric spectroscopy on three such systems, covering a broad temperature and dynamic range that extends from the low-viscosity liquid around room temperature down to the glassy state approaching the glass-transition temperature. We detect a relaxational process that can be ascribed to dipolar reorientational dynamics and exhibits the clear signatures of glassy freezing. We find that the temperature dependence of the ionic dc conductivity and its room-temperature value also are governed by the glassy dynamics of these systems, depending, e.g., on the glass-transition temperature and fragility. Compared to the previously investigated corresponding systems, containing choline chloride instead of a lithium salt, both the reorientational and ionic dynamics are significantly reduced due to variations in the glass-transition temperature and the higher ionic potential of the lithium ions. These lithium-based deep eutectic solvents partly exhibit significant decoupling of the dipolar reorientational and the ionic translational dynamics and approximately follow a fractional Debye-Stokes-Einstein relation, leading to an enhancement of the dc conductivity, especially at low temperatures. The presented results clearly reveal the importance of decoupling effects and of the typical glass-forming properties of these systems for the technically relevant room-temperature conductivity.
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Affiliation(s)
- A Schulz
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - P Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - A Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
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10
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Pan H, Luo J, Li B, Wübbenhorst M. Phase-dependent dielectric properties and proton conduction of neopentyl glycol. RSC Adv 2021; 11:23228-23234. [PMID: 35479796 PMCID: PMC9036410 DOI: 10.1039/d1ra03366b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/22/2021] [Indexed: 12/17/2022] Open
Abstract
Phase-dependent dielectric properties and proton conduction of neopentyl glycol (NPG), which is an organic molecular plastic crystal, were studied via variable-temperature broadband dielectric spectroscopy (BDS). Permittivity and conductivity data show the phase transformations of NPG from the crystalline state to the plastic crystalline state at 315 K and then to the molten state at 402 K across the temperature range of 293–413 K. The Vogel temperatures (Tv) fitted from the Vogel–Fulcher–Tammann (VFT) equation agree well with the values extrapolated by the Stickel plot (linearized Vogel plot). Impedance and modulus data display a separation of the −Z′′ (the imaginary part of the complex impedance) and M′′ (the imaginary part of the complex electric modulus) peaks in the crystalline phase. However, they overlap in both the plastic crystalline phase and the molten phase, indicating long-range proton conduction. In both the molten phase and the plastic crystalline phase, the temperature dependence of direct current conductivity (σdc) obeys the VFT equation very well. While the vehicle mechanism (translational diffusion) is an intrinsic mechanism for ionic or protonic conduction in the molten phase, it is speculated that the Grotthuss mechanism also works due to the self-dissociation of NPG molecules, which are similar to water molecules. In the plastic crystalline phase, the proton hopping mechanism is most likely the underlying ion-conducting mechanism because of the rotational disorder and intrinsic defects (vacancies) of the NPG molecules. In the ordered crystalline phase, the proton conduction is presumed to follow the proton hopping mechanism as determined from the localized relaxation and the temperature dependence of σdc (Arrhenius behavior). Phase-dependent dielectric properties and proton conduction of neopentyl glycol (NPG) are studied systematically over a wide temperature range via broadband dielectric spectroscopy.![]()
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Affiliation(s)
- Hailong Pan
- College of Materials Science and Engineering, Sichuan University Chengdu 610065 China .,Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven Leuven 3001 Belgium
| | - Jiangshui Luo
- College of Materials Science and Engineering, Sichuan University Chengdu 610065 China .,Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven Leuven 3001 Belgium
| | - Bing Li
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences 72 Wenhua Road Shenyang Liaoning 110016 China
| | - Michael Wübbenhorst
- Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven Leuven 3001 Belgium
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11
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Saini S, Balani K, Maiti T. The analysis of charge transport mechanism in mixed ionic electronic conductor composite of Sr 2TiCoO 6double perovskite with yttria stabilized zirconia. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:315703. [PMID: 34132203 DOI: 10.1088/1361-648x/ac0283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/18/2021] [Indexed: 06/12/2023]
Abstract
In this investigation, the ionic conduction mechanism in mixed ionic electronic conductors composites of Sr2TiCoO6/YSZ has been studied with the help of universal dynamic response. 3 mol% and 8 mol% yttria stabilized ZrO2have been mixed with Sr2TiCoO6(STC) double perovskite in 1:1 ratio to prepare STC/3YSZ and STC/8YSZ composites via solid-state reaction route. AC Impedance spectroscopy has been carried out to examine the charge transport mechanism, which has been modeled using the microstructural networks of resistors and capacitors. Grain boundaries are more resistive and capacitive compared to the bulk. Modulus spectroscopy analysis demonstrates the non-Debye character of conductivity relaxation with frequency. Complex frequency-dependent AC conductivity is found to obey Almond West power law and reveals that ion migration occurs through the correlated hopping mechanism. Further, the DC conductivity and relaxation time have been found to follow the Barton Nakajima and Namikawa relation, which is correlated with AC to DC conduction. The time-temperature superposition principle has been used to explain the conductivity scaling in the intermediate frequency range. At low temperatures, the ions are localized in the asymmetric potential well, while at high temperatures, hopping behavior starts dominating. Further Kramers-Kronig transformation connects the dielectric strength with conductivity relaxation and verifies the impedance data.
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Affiliation(s)
- Sudha Saini
- Plasmonic and Perovskites Laboratory, Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, UP 208016, India
- Biomaterials Laboratory, Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, UP 208016, India
| | - Kantesh Balani
- Biomaterials Laboratory, Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, UP 208016, India
| | - Tanmoy Maiti
- Plasmonic and Perovskites Laboratory, Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, UP 208016, India
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12
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Reuter D, Münzner P, Gainaru C, Lunkenheimer P, Loidl A, Böhmer R. Translational and reorientational dynamics in deep eutectic solvents. J Chem Phys 2021; 154:154501. [DOI: 10.1063/5.0045448] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- D. Reuter
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - P. Münzner
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - C. Gainaru
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - P. Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - A. Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - R. Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
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13
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Wrzesińska A, Wypych-Puszkarz A, Bobowska I, Ulański J. Effects of Counter Anions on AC and DC Electrical Conductivity in Poly(Dimethylsiloxane) Crosslinked by Metal-Ligand Coordination. Polymers (Basel) 2021; 13:polym13060956. [PMID: 33804697 PMCID: PMC8003853 DOI: 10.3390/polym13060956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 11/16/2022] Open
Abstract
There is an urgent need for the development of elastic dielectric materials for flexible organic field effect transistors (OFETs). In this work, detailed analysis of the AC and DC electrical conductivity of a series of flexible poly(dimethylsiloxane) (PDMS) polymers crosslinked by metal-ligand coordination in comparison to neat PDMS was performed for the first time by means of broadband dielectric spectroscopy. The ligand was 2,2-bipyridine-4,4-dicarboxylic amide, and Ni2+, Mn2+, and Zn2+ were introduced for Cl−, Br−, and I− salts. Introduction of metal salt and creation of coordination bonds resulted in higher permittivity values increasing in an order: neat PDMS < Ni2+ < Mn2+ < Zn2+; accompanied by conductivity values of the materials increasing in an order: neat PDMS < Cl− < I− < Br−. Conductivity relaxation time plot as a function of temperature, showed Vogel-Fulcher–Tammann dependance for the Br− salts and Arrhenius type for the Cl− and I− salts. Performed study revealed that double-edged challenge can be obtained, i.e., dielectric materials with elevated value of dielectric permittivity without deterioration too much the non-conductive nature of the polymer. This opens up new perspectives for the production of flexible dielectrics suitable for gate insulators in OFETs. Among the synthesized organometallic materials, those with chlorides salts are the most promising for such applications.
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Affiliation(s)
| | | | | | - Jacek Ulański
- Correspondence: (A.W.-P.); (J.U.); Tel.: +48-42-631-32-05 (A.W.-P.)
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14
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Reuter D, Seitz K, Lunkenheimer P, Loidl A. Ionic conductivity and relaxation dynamics in plastic crystals with nearly globular molecules. J Chem Phys 2020; 153:014502. [PMID: 32640802 DOI: 10.1063/5.0012430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have performed a dielectric investigation of the ionic charge transport and the relaxation dynamics in plastic crystalline 1-cyano-adamantane (CNA) and in two mixtures of CNA with the related plastic crystals adamantane or 2-adamantanon. Ionic charge carriers were provided by adding 1% of Li salt. The molecules of these compounds have nearly globular shape and, thus, the so-called revolving-door mechanism assumed to promote ionic charge transport via molecular reorientations in other PC electrolytes should not be active here. Indeed, a comparison of the dc resistivity and the reorientational α-relaxation times in the investigated PCs reveals complete decoupling of both dynamics. Similar to other PCs, we find a significant mixing-induced enhancement of the ionic conductivity. Finally, these solid-state electrolytes reveal a second relaxation process, slower than the α-relaxation, which is related to ionic hopping. Due to the mentioned decoupling, it can be unequivocally detected and is not superimposed by the reorientational contributions as found for most other ionic conductors.
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Affiliation(s)
- D Reuter
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - K Seitz
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - P Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - A Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
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15
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Davidowski SK, Yarger JL, Richert R, Angell CA. Reorientation Times for Solid-State Electrolyte Solvents and Electrolytes from NMR Spin-Lattice Relaxation Studies. J Phys Chem Lett 2020; 11:3301-3304. [PMID: 32242412 DOI: 10.1021/acs.jpclett.0c00502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Ionic and molecular plastic crystals have been studied recently as solid electrolytes or solvents, but the specific role of molecular reorientation has not been clarified. We use NMR spin-lattice relaxation times (T1 minima) to compare the time scale for magnetic fluctuations in a plastic crystal solvent to the molecular reorientation times, as established by dielectric spectroscopy. We focus on a mixture of succinonitrile and glutaronitrile, in which the rotationally disordered phase is stabilized against crystallization. Reorientation times can then be studied over 13 orders of magnitude, down to the glass transition temperature at 144 K. For each nucleus, 1H and 13C, the most probable magnetic fluctuation time is found to be slightly shorter than the reorientation time, but with practically indistinguishable temperature dependence. This facilitates investigation of the relation of solvent reorientation to ion conductivity relaxation times in ionic conducting systems in which the conductivity swamps the dielectric signature of solvent reorientation.
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Affiliation(s)
- S K Davidowski
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - J L Yarger
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - R Richert
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - C A Angell
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
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16
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On the interplay between the local structure and dynamics in low concentration mixtures of H2O and HOD in the [Emim+][TF2N−] room temperature ionic liquid. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111135] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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17
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Reuter D, Lunkenheimer P, Loidl A. Plastic-crystalline solid-state electrolytes: Ionic conductivity and orientational dynamics in nitrile mixtures. J Chem Phys 2019; 150:244507. [PMID: 31255051 DOI: 10.1063/1.5110404] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many plastic crystals, molecular solids with long-range, center-of-mass crystalline order but dynamic disorder of the molecular orientations, are known to exhibit exceptionally high ionic conductivity. This makes them promising candidates for applications as solid-state electrolytes, e.g., in batteries. Interestingly, it was found that the mixing of two different plastic-crystalline materials can considerably enhance the ionic dc conductivity, an important benchmark quantity for electrochemical applications. An example is the admixture of different nitriles to succinonitrile, the latter being one of the most prominent plastic-crystalline ionic conductors. However, until now, only few such mixtures were studied. In the present work, we investigate succinonitrile mixed with malononitrile, adiponitrile, and pimelonitrile to which 1 mol. % of Li ions was added. Using differential scanning calorimetry and dielectric spectroscopy, we examine the phase behavior and the dipolar and ionic dynamics of these systems. We especially address the mixing-induced enhancement of the ionic conductivity and the coupling of the translational ionic mobility to the molecular reorientational dynamics, probably arising via a "revolving-door" mechanism.
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Affiliation(s)
- D Reuter
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - P Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - A Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
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18
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Beerwerth J, Bierwirth SP, Adam J, Gainaru C, Böhmer R. Local and global dynamics of the viscous ion conductors 2Ca(NO3)2-3KNO3 and 2Ca(NO3)2-3RbNO3 probed by 87Rb nuclear magnetic resonance and shear rheology. J Chem Phys 2019; 150:194503. [DOI: 10.1063/1.5093973] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Joachim Beerwerth
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - S. Peter Bierwirth
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Jens Adam
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Catalin Gainaru
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Roland Böhmer
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
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19
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Reuter D, Binder C, Lunkenheimer P, Loidl A. Ionic conductivity of deep eutectic solvents: the role of orientational dynamics and glassy freezing. Phys Chem Chem Phys 2019; 21:6801-6809. [DOI: 10.1039/c9cp00742c] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dielectric spectroscopy reveals that the ionic conductivity of deep eutectic solvents is closely coupled to their reorientational dipolar relaxation dynamics.
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Affiliation(s)
- Daniel Reuter
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg
- 86135 Augsburg
- Germany
| | - Catharina Binder
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg
- 86135 Augsburg
- Germany
| | - Peter Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg
- 86135 Augsburg
- Germany
| | - Alois Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg
- 86135 Augsburg
- Germany
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20
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Jafta CJ, Bridges C, Haupt L, Do C, Sippel P, Cochran MJ, Krohns S, Ohl M, Loidl A, Mamontov E, Lunkenheimer P, Dai S, Sun XG. Ion Dynamics in Ionic-Liquid-Based Li-Ion Electrolytes Investigated by Neutron Scattering and Dielectric Spectroscopy. CHEMSUSCHEM 2018; 11:3512-3523. [PMID: 30133183 DOI: 10.1002/cssc.201801321] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/30/2018] [Indexed: 06/08/2023]
Abstract
A detailed understanding of the diffusion mechanisms of ions in pure and doped ionic liquids remains an important aspect in the design of new ionic-liquid electrolytes for energy storage. To gain more insight into the widely used imidazolium-based ionic liquids, the relationship between viscosity, ionic conductivity, diffusion coefficients, and reorientational dynamics in the ionic liquid 3-methyl-1-methylimidazolium bis(trifluoromethanesulfonyl)imide (DMIM-TFSI) with and without lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) was examined. The diffusion coefficients for the DMIM+ cation and the role of ion aggregates were investigated by using the quasielastic neutron scattering (QENS) and neutron spin echo techniques. Two diffusion mechanisms are observed for the DMIM+ cation with and without Li-TFSI, that is, translational and local. The data additionally suggest that Li+ ion transport along with ion aggregates, known as the vehicle mechanism, may play a significant role in the ion diffusion process. These dielectric-spectroscopy investigations in a broad temperature and frequency range reveal a typical α-β-relaxation scenario. The α relaxation mirrors the glassy freezing of the dipolar ions, and the β relaxation exhibits the signatures of a Johari-Goldstein relaxation. In contrast to the translational mode detected by neutron scattering, arising from the decoupled faster motion of the DMIM+ ions, the α relaxation is well coupled to the dc charge transport, that is, the average translational motion of all three ion species in the material. The local diffusion process detected by QENS is only weakly dependent on temperature and viscosity and can be ascribed to the typical fast dynamics of glass-forming liquids.
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Affiliation(s)
- Charl J Jafta
- Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Craig Bridges
- Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Leon Haupt
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159, Augsburg, Germany
| | - Changwoo Do
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Pit Sippel
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159, Augsburg, Germany
| | - Malcolm J Cochran
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Stephan Krohns
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159, Augsburg, Germany
| | - Michael Ohl
- Jülich Centre for Neutron Science, Forschungszentrum Jülich, 52428, Jülich, Germany
| | - Alois Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159, Augsburg, Germany
| | - Eugene Mamontov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Peter Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159, Augsburg, Germany
| | - Sheng Dai
- Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA
| | - Xiao-Guang Sun
- Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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21
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Novak E, Jalarvo N, Gupta S, Hong K, Förster S, Egami T, Ohl M. Dynamics in the Plastic Crystalline Phases of Cyclohexanol and Cyclooctanol Studied by Quasielastic Neutron Scattering. J Phys Chem B 2018; 122:6296-6304. [PMID: 29775540 DOI: 10.1021/acs.jpcb.8b03448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Plastic crystals are a promising candidate for solid state ionic conductors. In this work, quasielastic neutron scattering is employed to investigate the center of mass diffusive motions in two types of plastic crystalline cyclic alcohols: cyclohexanol and cyclooctanol. Two separate motions are observed which are attributed to long-range translational diffusion (α-process) and cage rattling (fast β-process). Residence times and diffusion coefficients are calculated for both processes, along with the confinement distances for the cage rattling. In addition, a binary mixture of these two materials is measured to understand how the dynamics change when a second type of molecule is added to the matrix. It is observed that, upon the addition of the larger cyclooctanol molecules into the cyclohexanol solution, the cage size decreases, which causes a decrease in the observed diffusion rates for both the α- and fast β-processes.
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Affiliation(s)
- E Novak
- Department of Materials Science and Engineering , University of Tennessee , Knoxville , Tennessee 37996 , United States.,Neutron Sciences Directorate , Oak Ridge National Laboratory (ORNL) , Oak Ridge , Tennessee 37831 , United States.,Jülich Centre for Neutron Science (JCNS) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
| | - N Jalarvo
- Neutron Sciences Directorate , Oak Ridge National Laboratory (ORNL) , Oak Ridge , Tennessee 37831 , United States.,Jülich Centre for Neutron Science (JCNS) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
| | - S Gupta
- Department of Chemistry and Macromolecular Studies Group , Louisiana State University , Baton Rouge , Louisiana 70803 , United States
| | - K Hong
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory (ORNL) , Oak Ridge , Tennessee 37831 , United States.,Department of Chemical and Biomolecular Engineering , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | - S Förster
- Jülich Centre for Neutron Science (JCNS) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
| | - T Egami
- Department of Materials Science and Engineering , University of Tennessee , Knoxville , Tennessee 37996 , United States.,Materials Science and Technology Division , Oak Ridge National Laboratory (ORNL) , Oak Ridge , Tennessee 37831 , United States.,Department of Physics and Astronomy , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | - M Ohl
- Jülich Centre for Neutron Science (JCNS) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
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22
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Reuter D, Geiß C, Lunkenheimer P, Loidl A. Variation of ionic conductivity in a plastic-crystalline mixture. J Chem Phys 2017; 147:104502. [PMID: 28915741 DOI: 10.1063/1.5001946] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ionically conducting plastic crystals (PCs) are possible candidates for solid-state electrolytes in energy-storage devices. Interestingly, the admixture of larger molecules to the most prominent molecular PC electrolyte, succinonitrile, was shown to drastically enhance its ionic conductivity. Therefore, binary mixtures seem to be a promising way to tune the conductivity of such solid-state electrolytes. However, to elucidate the general mechanisms of ionic charge transport in plastic crystals and the influence of mixing, a much broader database is needed. In the present work, we investigate mixtures of two well-known plastic-crystalline systems, cyclohexanol and cyclooctanol, to which 1 mol. % of Li ions were added. Applying differential scanning calorimetry and dielectric spectroscopy, we present a thorough investigation of the phase behavior and the ionic and dipolar dynamics of this system. All mixtures reveal plastic-crystalline phases with corresponding orientational glass-transitions. Moreover, their conductivity seems to be dominated by the "revolving-door" mechanism, implying a close coupling between the ionic translational and the molecular reorientational dynamics of the surrounding plastic-crystalline matrix. In contrast to succinonitrile-based mixtures, there is no strong variation of this coupling with the mixing ratio.
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Affiliation(s)
- D Reuter
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - C Geiß
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - P Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - A Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
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23
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Gainaru C, Stacy EW, Bocharova V, Gobet M, Holt AP, Saito T, Greenbaum S, Sokolov AP. Mechanism of Conductivity Relaxation in Liquid and Polymeric Electrolytes: Direct Link between Conductivity and Diffusivity. J Phys Chem B 2016; 120:11074-11083. [PMID: 27681664 DOI: 10.1021/acs.jpcb.6b08567] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Combining broadband impedance spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance we analyzed charge and mass transport in two polymerized ionic liquids and one of their monomeric precursors. In order to establish a general procedure for extracting single-particle diffusivity from their conductivity spectra, we critically assessed several approaches previously employed to describe the onset of diffusive charge dynamics and of the electrode polarization in ion conducting materials. Based on the analysis of the permittivity spectra, we demonstrate that the conductivity relaxation process provides information on ion diffusion and the magnitude of cross-correlation effects between ionic motions. A new approach is introduced which is able to estimate ionic diffusivities from the characteristic times of conductivity relaxation and ion concentration without any adjustable parameters. This opens the venue for a deeper understanding of charge transport in concentrated and diluted electrolyte solutions.
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Affiliation(s)
- C Gainaru
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.,Fakultät Physik, Technische Universität Dortmund , D-44221 Dortmund, Germany
| | - E W Stacy
- Department of Physics and Astronomy, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - V Bocharova
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - M Gobet
- Department of Physics & Astronomy, Hunter College of The City University of New York , New York, New York 10065, United States
| | - A P Holt
- Department of Physics and Astronomy, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - T Saito
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - S Greenbaum
- Department of Physics & Astronomy, Hunter College of The City University of New York , New York, New York 10065, United States
| | - A P Sokolov
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.,Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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