Sulfide solid electrolytes offer great opportunities to construct solid-state Li metal batteries with high energy density. The high ionic conductivity of well-developed sulfide electrolytes enables solid-state battery to operate at high current rates. However, sulfide electrolytes exhibit severe decomposition in working cells, constituting a significant obstacle for the practical applications of sulfide solid-state electrolytes. The decomposition behaviors of sulfides are complicated and strongly depend on the electrochemical windows, some of which are even regarded reversible during battery cycling. Herein, we investigate the redox behaviors of Li₇P₃S₁₁ sulfide electrolyte under different voltage windows, and their effects on interfacial transport and battery cycle lifetime. Moreover, Li metal | Li₄Ti₅O₁₂ (LTO) batteries are introduced to further probe the role of multiphase redox reactions on interfacial ion conduction. By regulating the redox behaviors through working voltage window, Li | LTO metal batteries enable a rapid charge/discharge process in 10 min (6 C) and lifespan of 600 cycles at 1 C with 85% capacity retention. An all-solid-state Li | LTO metal pouch cell is also assembled and exhibits a stable cycling performance with a capacity of 120 mAh g⁻¹. This work provides understandings about interfacial redox behaviors of sulfide electrolyte, presenting novel insights in the rational design of future solid-state lithium batteries with high-energy/power-density.

硫化物固体电解质为构建高能量密度的固态锂金属电池提供了巨大的机会。发达的硫化物电解质的高离子电导率使固态电池能够以高电流速率运行。然而，硫化物电解质在工作单元中表现出严重的分解，这对硫化物固态电解质的实际应用构成了重大障碍。硫化物的分解行为很复杂，并且强烈依赖于电化学窗口，其中一些甚至在电池循环期间被认为是可逆的。本文中，我们研究了Li ₇ P ₃ S ₁₁的氧化还原行为。硫化物在不同电压窗口下的电解质及其对界面迁移和电池循环寿命的影响。此外，锂金属| 引入Li ₄ Ti ₅ O ₁₂（LTO）电池以进一步探讨多相氧化还原反应在界面离子传导中的作用。通过工作电压窗口调节氧化还原行为，LTO金属电池可在10分钟（6 C）内实现快速充电/放电过程，在1 C下具有600个循环的寿命，并具有85％的容量保持率。全固态李| 还组装了LTO金属袋式电池，并表现出稳定的循环性能，容量为120 mAh g ^-1。这项工作提供了关于硫化物电解质的界面氧化还原行为的理解，为未来的高能量/功率密度固态锂电池的合理设计提供了新颖的见解。