Tuning the Formation and Structure of the Silicon Electrode/Ionic Liquid Electrolyte Interphase in Superconcentrated Ionic Liquids

The latest advances in the stabilization of Li/Na metal battery and Li-ion cycling have highlighted importance electrode/electrolyte interface [solid electrolyte interphase (SEI)] its direct link to behavior. To understand structure properties SEI, we used combined experimental computational studies unveil how ionic liquid (IL) cation nature salt concentration impact silicon/IL interfacial formed SEI. IL is found be important control reductive decomposition that influences SEI composition reversibility Li–Si alloying process. Also, increasing Li changes for a favorable less resistive most promising Si-based was P1222FSI with 3.2 m LiFSI, which leads an optimal after 100 cycles LiF trapped LiFSI are only distinguishable lithiated fluorinated products detected. This study shows clear between nanostructure near electrode surface, resulting Si negative performance. More importantly, this work will aid rational design batteries using electrolytes area has so far been neglected, reinforcing benefits superconcentrated systems.