Spontaneous gas-solid reaction on sulfide electrolytes for high-performance all-solid-state batteries

Sulfide electrolytes with high ionic conductivity and facile formability are expected to replace the conventional flammable liquid electrolyte to construct high-energy and safe all-solid-state batteries (ASSBs). However, the practical use of sulfide electrolytes is mainly obstructed by their high sensitivity to humidity and instability to the high-voltage oxide cathodes. Herein, we solve these two problems of sulfide electrolytes by constructing a Li2CO3 interface through a spontaneous gas-solid reaction and achieve the enhanced electrochemical performance of ASSBs. Coupled with bare LiCoO2, the ASSBs with CO2-treated electrolyte or fabricated in a CO2-rich environment show impressive electrochemical performance with a remarkable rate performance (65 mA h g(-1) at 3C) and excellent cycling retention (89.4% retention over 2100 cycles) at voltage up to 4.5 V vs. Li+/Li. The improved performance is attributed to the enhanced interfacial stability with low resistance and demonstrates the practical feasibility and even superiority of sulfide electrolytes based on current battery fabrication conditions.