Computer-Aided Multifunctional Ionic Liquid Design for the Electrolyte in LTO Rechargeable Batteries

A computer-aided ionic liquid design (CAILD) method was employed to screen suitable ionic liquids (ILs) for use as additives in electrolytes. By formulating and solving a CAILDbased mixed-integer non-linear programming problem, 100 ILs with desired properties were systematically and rapidly identified from 1,089,450 candidates. Subsequently, a new type of IL, 3-(2 amino-2-ox o e t h y l )-1-v i n y l i m i d a z o l i u m b i s(trifluoromethylsulfonyl)amide ([VAIM][TFSA]), was selected due to its unsaturated functional groups such as vinyl and amide as it may potentially inhibit the water and HF contents in the electrolyte. As a proof of concept, this IL was synthesized for the first time, and then, some electrolytes containing 0, 0.5, 1.0, and 3.0 wt % [VAIM][TFSA] were systemically studied in LTO/Li batteries. Our results reveal that the basic groups of [VAIM][TFSA] are capable of slowing down the release of water and HF in the electrolyte for a long time, while the unsaturated vinyl group could promote the formation of the film on the anode. Remarkably, cells with [VAIM][TFSA] (especially 0.5 wt %), after 300 cycles, present much higher specific capacity and better rate properties than their counterparts without the IL additive.