| Autor: |
Jayakody NK; Department of Physics and Astronomy, Hunter College of CUNY, New York, New York 10065, United States., Fraenza CC; Department of Physics and Astronomy, Hunter College of CUNY, New York, New York 10065, United States., Greenbaum SG; Department of Physics and Astronomy, Hunter College of CUNY, New York, New York 10065, United States., Ashby D; Department of Materials Science and Engineering, University of California, Los Angeles, California 90024, United States., Dunn BS; Department of Materials Science and Engineering, University of California, Los Angeles, California 90024, United States. |
| Jazyk: |
angličtina |
| Zdroj: |
The journal of physical chemistry. B [J Phys Chem B] 2020 Aug 06; Vol. 124 (31), pp. 6843-6856. Date of Electronic Publication: 2020 Jul 28. |
| DOI: |
10.1021/acs.jpcb.0c02755 |
| Abstrakt: |
We have investigated the charge transport dynamics of a novel solid-like electrolyte material based on mixtures of the ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM] TFSI) and various concentrations of lithium salt bis(trifluoromethylsulfonyl)imide (LiTFSI) confined within a SiO 2 matrix, prepared via a sol-gel method. The translational diffusion coefficients of BMIM + , TFSI - , and Li + in ILs and confined ILs (ionogels, IGs) with different concentrations of lithium salt have been measured at variable temperatures, covering the 20-100 °C range, using nuclear magnetic resonance (NMR) pulsed field gradient diffusion spectroscopy. The mobility of BMIM + , TFSI - , and Li + was found to increase with the [BMIM] TFSI/LiTFSI ratio, exhibiting an almost liquid-like mobility in IGs. Additionally, the effect of confinement on IL rotational dynamics has been analyzed by measuring 1 H, 19 F, and 7 Li spin-lattice relaxation rate dispersions of IGs at different temperatures, using fast field-cycling NMR relaxometry. The analysis of the experimental data was performed assuming the existence of two fractions of the liquid: a bulk fraction (at least several ionic radii from the silica particles) and a surface fraction (close to the silica particles) and using two different models based on translational and rotational diffusion and reorientation mediated by translational displacements. The existence and weighting of these two fractions of ions were obtained from the direct diffusion measurements. The results show that the ion dynamics slowed only modestly under confinement, which evidences that IGs preserve IL transport properties, and this behavior is an encouraging indication for using IGs as a solid electrolyte for Li + batteries. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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