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Concentrated Ionic-Liquid-Based Electrolytes for High-Voltage Lithium Batteries with Improved Performance at Room Temperature

Gao, Xinpei; Wu, Fanglin; Mariani, Alessandro; Passerini, Stefano

Ionic liquids (ILs) have been widely explored as alternative electrolytes to combat the safety issues associated with conventional organic electrolytes. However, hindered by their relatively high viscosity, the electrochemical performances of IL‐based cells are generally assessed at medium‐to‐high temperature and limited cycling rate. A suitable combination of alkoxy‐functionalized cations with asymmetric imide anions can effectively lower the lattice energy and improve the fluidity of the IL material. The Li/Li$_{1.2}$Ni$_{0.2}$Mn$_{0.6}$O$_{2}$ cell employing N‐N‐diethyl‐N‐methyl‐N‐(2‐methoxyethyl)ammonium (fluorosulfonyl)(trifluoromethanesulfonyl)imide (DEMEFTFSI)‐based electrolyte delivered an initial capacity of 153 mAh g$^{-1}$ within the voltage range of 2.5–4.6 V, with a capacity retention of 65.5 % after 500 cycles and stable coulombic efficiencies exceeding 99.5 %. Moreover, preliminary battery tests demonstrated that the drawbacks in terms of rate capability could be improved by using Li‐concentrated IL‐based electrolytes. The improved room‐temperature rate performance of these electrolytes was likely owing to the formation of Li$^{+}$‐containing aggregate species, changing the concentration‐dependent Li‐ion transport mechanism.

Verlagsausgabe §
DOI: 10.5445/IR/1000098141
Veröffentlicht am 26.01.2021
DOI: 10.1002/cssc.201901739
Zitationen: 28
Web of Science
Zitationen: 27
Zitationen: 29
Cover der Publikation
Zugehörige Institution(en) am KIT Helmholtz-Institut Ulm (HIU)
Publikationstyp Zeitschriftenaufsatz
Publikationsdatum 20.09.2019
Sprache Englisch
Identifikator ISSN: 1864-5631, 1864-564X
KITopen-ID: 1000098141
HGF-Programm 37.01.01 (POF III, LK 01) Fundamentals and Materials
Erschienen in ChemSusChem
Verlag Wiley-VCH Verlag
Band 12
Heft 18
Seiten 4185-4193
Vorab online veröffentlicht am 19.07.2019
Nachgewiesen in Web of Science
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