Sn-doped thioantimonate superionic conductors with high air stability and enhanced Li-ion conduction for all-solid-state lithium batteries

The sulfide-based solid electrolyte (SSE) has been considered as a strong candidate for potential uses in all-solid-state lithium batteries (ASSLBs). Nevertheless, most of the reported SSEs are plagued with their intrinsic air-sensitive behaviors and Li-incompatibility, which largely preclude scalable fabrication and widespread practical application. Herein, we report the Li6+xSb1-xSnxS5I (LSSSI-x) SSEs using nontoxic inexpensive Sn substitution to deal with these issues. The ionic conductivity of Li6+xSb1-xSnxS5I can achieve a maximum value of 3.49 x 10(-4) S cm(-1) at room temperature when x = 0.4, which is over 40-fold that of the pristine Li6SbS5I. The Li symmetric cell with I-rich Li6.4Sb0.6Sn0.4S5I (LSSSI-0.4) electrolyte delivers a stable Li+ plating/stripping behavior over 450 h at a current density of 0.1 mA cm(-2). Benefiting from the decent Li-compatibility of LSSSI-0.4, the assembled ASSLB with LiNi0.8Co0.1Mn0.1O2-based composite cathode and Li-metal anode displays good cycling performance. The LSSSI-0.4 electrolyte also possesses excellent moisture stability. ASSLB using the dried LSSSI-0.4 electrolyte still exhibits a well-maintained initial discharge capacity of 184.0 mA h g(-1) at 0.1C and an impressive capacity retention rate of 70.6% after 600 cycles at 0.2C. This work offers a feasible option with superior integrated properties to push forward the advancement of high-performance ASSLBs.