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Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature
Published on: December 20, 2016
Ionic liquid based lithium battery electrolytes: fundamental benefits of utilising both TFSI and FSI anions?
M Kerner1, N Plylahan, J Scheers
1Department of Applied Physics, Chalmers University of Technology, SE-41296 Gothenburg, Sweden. manfred.kerner@chalmers.se.
Abstract:
Several IL based electrolytes with an imidazolium cation (EMI) have been investigated trying to elucidate a possible beneficial effect of mixing FSI and TFSI anions in terms of physico-chemical properties and especially Li(+) solvation. All electrolytes were evaluated in terms of phase transitions, densities and viscosities, thermal stabilities, ionic conductivities and local structure, i.e. charge carriers. The electrolytes with up to 20% of Li-salts showed to be promising for high temperature lithium ion battery application (ca. 100 °C) and a synergetic effect of having mixed anions is discernible with the LiTFSI0.2EMIFSI0.8 electrolyte giving the best overall performance. The determination of the charge carriers revealed the SN to be ca. 2 for all analysed electrolytes, and proved the analysis of the mixed anion electrolytes to be challenging and inherently leads to an ambiguous picture of the Li(+) solvation.
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