High areal capacity, long cycle life 4 V ceramic all-solid-state Li-ion batteries enabled by chloride solid electrolytes

All-solid-state Li batteries (ASSBs) employing inorganic solid electrolytes offer improved safety and are exciting candidates for next-generation energy storage. Herein, we report a family of lithium mixed-metal chlorospinels, Li2InxSc0.666−xCl4 (0 ≤ x ≤ 0.666), with high ionic conductivity (up to 2.0 mS cm−1) owing to a highly disordered Li-ion distribution, and low electronic conductivity (4.7 × 10−10 S cm−1), which are implemented for high-performance ASSBs. Owing to the excellent interfacial stability of the SE against uncoated high-voltage cathode materials, ASSBs utilizing LiCoO2 or LiNi0.85Co0.1Mn0.05O2 exhibit superior rate capability and long-term cycling (up to 4.8 V versus Li+/Li) compared to state-of-the-art ASSBs. In particular, the ASSB with LiNi0.85Co0.1Mn0.05O2 exhibits a long life of >3,000 cycles with 80% capacity retention at room temperature. High cathode loadings are also demonstrated in ASSBs with stable capacity retention of >4 mAh cm−2 (~190 mAh g−1). Intensive research is underway to develop solid-state electrolytes for rechargeable batteries. Here the authors report a family of mixed-metal halospinel electrolytes that exhibits promising properties for high-performance solid-state batteries.