D.K. Jin, H.D. Shi *, Y.X. Ma, Y.Y. Liu, Y. Wang, Y.F. Dong, M.B. Wu * and Z.-S. Wu *

SusMat, 2024, Accepted.

Sulfide solid-state electrolytes (SSEs) with superior ionic conductivity and processability are highly promising candidates for constructing all-solid-state lithium metal batteries (ASSLMBs). However, their practical applications are limited by their intrinsic air instability and serious interfacial incompatibility. Herein, a novel glass-ceramic electrolyte Li3.12P0.94Bi0.06S3.91I0.18 is synthesized by co-doping Li3PS4 with Bi and I for high-performance ASSLMBs. Owing to the strong Bi-S bonds that are thermodynamically stable to water, increased unit cell volume and Li+ concentration caused by P5+ substitution with Bi3+, and the in situ formed robust solid electrolyte interphase layer LiI at lithium surface, the as-prepared Li3.12P0.94Bi0.06S3.91I0.18 SSE achieves excellent air stability with a H2S concentration of only 0.205 cm3 g−1 (after 300 min of air exposure) outperforming Li3PS4 (0.632 cm3 g−1) and the most reported sulfide SSEs, together with high ionic conductivity of 4.05 mS cm−1. Further, the Li3.12P0.94Bi0.06S3.91I0.18 effectively improves lithium metal stability. With this SSE, an ultralong cyclability of 700 h at 0.1 mA cm−2 is realized in a lithium symmetrical cell. Moreover, the Li3.12P0.94Bi0.06S3.91I0.18 based ASSLMBs with LiNi0.8Mn0.1Co0.1O2 cathode achieve ultrastable capacity retention rate of 95.8% after 300 cycles at 0.1 C. This work provides reliable strategy for designing advanced sulfide SSEs for commercial applications in ASSLMBs.