Electrolyte Design for Silicon-Based Li-Ion Battery Guided by Chemical Reactivity of Solvents with a Model Silicon Anode

The use of a model compound trimethylsilyllithium was demonstrated to study the chemical reactions of electrolyte with as a principal guide to design electrolyte for silicon-based Li-ion battery. Me3Si– anion initiates ring-opening polymerization of EC leading to the formation of poly(ethylene ether carbonate), which subsequently defragments into oligomers and dissolves in electrolyte. FEC was found to react differently, generating LiF and vinylene carbonate (VC). Further reaction of VC with Me3SiLi generated poly(hydroxymethylene), which is a nonsoluble polymer and the critical SEI component. The insights from this study have guided the new electrolyte design for the Si-based battery.