High‐Capacity, Long‐Life Sulfide All‐Solid‐State Batteries with Single‐Crystal Ni‐Rich Layered Oxide Cathodes

Sulfide all‐solid‐state battery (SASSB) with ultrahigh‐nickel layered oxide cathode (LiNi x Co y Mn 1‐x‐y O 2 , NCM, x ≥ 0.9) offers the potential of high energy density and safety for superior energy storage systems. However, stable cycling is difficult to realize due to adverse interfacial reactions, space charge layer (SCL), and elemental diffusion. Herein, a straightforward solid‐phase coating strategy is exploited to synthesize Ni90‐S cathode, which greatly improves the charge transmission capability of the composite cathode and suppresses interfacial reactions in SASSB. The consequent SC‐Ni90‐0.2%S/Li 6 PS 5 Cl/Li 4 Ti 5 O 12 SASSB exhibits enhanced electrochemical performance, including a long life of 500 cycles with 87% capacity retention at 1C, high areal capacity of 11.44 mAh cm −2 , and excellent rate performance at 20 C. These results promise an efficient strategy for designing cathode materials for SASSBs.