Imidazolium‐Based Protic Ionic Liquids as Electrolytes for Lithium‐Ion Batteries

Abstract

Abstract Protic ionic liquids (PILs) have been indicated as a promising class of ionic liquids (ILs) for the realization of high‐performance lithium‐ion batteries (LIBs). In this work we synthesize four different PILs containing the imidazolium‐based cations 1,2‐Dimethylimidazolium (1,2‐DMim + ) and 1‐Methylimidazolium (1‐Mim + ), and the anions bis(trifluoromethanesulfonyl)imide (TFSI − ) and bis(fluorosulfonyl)imide (FSI − ). We show that these PILs display good conductivities and low viscosities and that they can be successfully used in combination with lithium iron phosphate (LFP) electrodes. Among the investigated electrolytes, 0.5 M LiTFSI in 1,2‐DMImTFSI appears as the most promising candidate for the realization of systems with high capacity retentions at high C‐rates and high cycling stabilities.