Microstructure-tailored Ni-rich cathode with fast Li⁺ diffusion layer boosts high-rate and long-cycling all-solid-state batteries

All-solid-state batteries (ASSBs) incorporating Ni-rich cathodes and sulfide solid electrolytes are promising for next-generation energy storage. However, their performance is constrained by the inherent electrochemo-mechanical instability and sluggish Li⁺ diffusion kinetics in the randomly oriented Ni-rich cathodes. Herein, we present a microstructure-tailored Ni-rich cathode with fast Li⁺ diffusion layer through regulation of primary particle size and distribution. Comprehensive investigations demonstrate that this optimized Ni-rich cathode enables rapid Li⁺ transport kinetics and effectively accommodates strain accumulation during cycling. Furthermore, an in situ -formed Li₂CO₃ coating on the cathode surface provides robust passivation against sulfide electrolyte decomposition at the interface. Consequently, sulfide-based ASSBs employing this Ni-rich cathode exhibit a high reversible capacity of 233.8 mAh g⁻¹ and remarkable capacity retention of 79% after 1,000 cycles at 1 C and 71% after 10,000 cycles at 5 C. This work provides an effective and scalable strategy for designing high-performance Ni-rich cathodes, paving the way for high-energy-density and long-lifespan ASSBs.