High ionic conductivity with improved battery stability of In3+/I- co-doped Li7P3S11 solid electrolytes

Sulfide solid electrolytes (SSEs) are promising materials for developing safe and high-performance all-solid-state lithium batteries (ASSLBs). However, enhancing the ionic conductivity, air stability, and electrolyte/electrode interface compatibility of vulcanized solid electrolytes simultaneously remains a significant challenge. Here, we propose a dual doping strategy (In 2 S 3 and LiI) based on liquid-phase method for the preparation of SSEs. In 2 S 3 and LiI can widen the Li + diffusion pathways and enhance the ionic conductivity. Meanwhile, In 2 S 3 can enhance the (electro)chemical stability and suppress the formation of lithium dendrites and H 2 S. Consequently, the prepared Li 7 P 2.94 In 0.1 S 10.9375 I 0.125 (LPInSI) solid electrolyte exhibited high ionic conductivity (2 mS·cm −1 ), excellent electrochemical stability, and air stability at 25 ℃. Based on this, ASSLBs fabricated with Li-In alloy anodes enhance the compatibility of the electrolyte/electrode interface, deliver a discharge capacity of 165.2 mAh·g −1 at room temperature, and retain 87.6 % of the specific discharge capacity after 300 cycles at 0.2 C. This study offers a viable approach for the synthesis of practical SSEs and high-performance ASSLBs.