(Invited) Highly-Stable Li Ion Batteries Based on Porous Si Anode and Localized High Concentration Electrolytes

Abstract

Si is one of the most promising anode materials for the next generation of lithium (Li) ion batteries (LIBs). Stability of Si based anode mainly depends on two factors: one is a nano-structures Si which can tolerate large volume change during Li injection/extraction process and also have a small surface area which can minimize the side reaction between Si and electrolyte, another is a stable SEI layer formed on the surface of porous Si which are highly conductive and mechanically stable during cycling process. In this work, we report a scalable approach to prepare nano-structured Si particles in combination with a highly stable SEI layer formed in Localized High Concentration Electrolytes (LHCE) tailored for Si based LIBs. Both Si||LiCoO2 and Si||LiNi0.6Mn0.2Co0.2O2 batteries with a high-loading Si based anode developed in this work can retain more than 90% capacity after 500 cycles. Comparing with the baseline electrolyte, the new electrolytes developed in this work enabled a more then 30% increase in cycle life of Si based Li ion batteries. Therefore, the combination of the porous Si anode and the novel electrolytes developed in this work can enable long term cycling of high energy LIBs required for both electrical vehicles and consumer electronics applications.