Enhancing Moisture and Electrochemical Stability of the LiPSCl Electrolyte by Oxygen Doping.

Chlorine-rich argyrodite-type solid electrolyte LiPSCl has been a promising choice for solid-state batteries (SSBs) because of its ultrafast Li-ion conduction. However, the poor air/moisture stability and low electrochemical stability with pristine high-voltage cathodes hinder their applications. Herein, O-substituted LiPSOCl ( = 0, 0.075, 0.175, and 0.25) solid electrolytes are successfully synthesized. Among them, LiPSOCl delivers high ionic conductivity, improved moisture resistance, and enhanced electrochemical stability in higher voltage windows. SSBs using LiPSOCl show higher capacities and superior cyclability than those using LiPSCl combined with a pristine LiNiMnCoO cathode when operated at a high end-of-charge voltage of 4.5 V (vs Li/Li). Moreover, the batteries exhibit outstanding performance in a wide temperature range. This work provides a strategy to modify the inherent drawbacks of sulfide electrolytes, promoting their practical applications.