Electronic-State Continuity Across a Heterointerphase of High-Capacity Ni-Rich Cathode for Stable Sulfide-Based All-Solid-State Lithium Batteries

Sulfide-based all-solid-state lithium batteries are severely constrained by the intertwined challenges of interfacial instability and sluggish lithium-ion kinetics at the nickel-rich layered oxide cathode interface. Herein, we report a design principle centered on electronic-state continuity across a cathode heterointerphase to simultaneously address these issues. By co-doping single-crystal LiNi_0.94Co_0.04Mn_0.02O₂ with selected period-5 elements (Y, Zr, Nb, and Mo), a self-assembled heterointerphase with spatially differentiated functions is achieved. Thermodynamically driven segregation yields a LiNbO₃/Li₂MoO₄ outer passivation layer that suppresses side reactions, which remains coherent with a subsurface Y/Zr-enriched rocksalt interlayer that anchors lattice oxygen. Crucially, the energetically continuous distribution of unoccupied 4d orbital-derived electronic states across the heterointerphase establishes an efficient charge redistribution channel and induces a well-oriented built-in electric field that screens the space-charge barrier, thereby driving accelerated interfacial Li⁺ transport. Consequently, the optimized cathode delivers a high specific capacity of 204.4 mAh g⁻¹ at 0.1 C and maintains 86.7% capacity retention over 1000 cycles at 0.5 C when paired with a Li₆PS₅Cl solid-state electrolyte. This orbital-level electronic engineering strategy provides a promising design principle for integrating chemical passivity and ionic transport kinetics in high-capacity all-solid-state energy storage systems.