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

ABSTRACT 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 0.94 Co 0.04 Mn 0.02 O 2 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 LiNbO 3 /Li 2 MoO 4 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 4 d 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 Li 6 PS 5 Cl 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.