Deciphering the Interfacial Li-Ion Migration Kinetics of Ni-Rich Cathodes in Sulfide-Based All-Solid-State Batteries

Nickel-rich layered oxide with high reversible capacity and high working potentials is a prevailing cathode for high-energy-density all-solid-state lithium batteries (ASSLBs). However, compared to the liquid battery system, ASSLBs suffer from poor Li-ion migration kinetics, severe side reactions, and undesired formation of space charge layers, which result in restricted capacity release and limited rate capability. In this work, we reveal that the capacity loss lies in the H2-H3 phase transition period, and we propose that the inconsistent interfacial Li-ion migration is the arch-criminal. We introduce Si doping to stabilize the bulk structure and Li