Tuning the Lithium Diffusion Kinetics in Co-Free Layered Cathodes for High-Performance All-Solid-State Batteries

All-solid-state batteries (ASSBs) with layered cathodes and sulfide solid electrolytes are promising for next-generation batteries due to their high energy density and safety. However, the use of Co-free and Ni-rich layered cathodes limits performance because of slow Li+ diffusion and mechanical degradation. This study demonstrates that these challenges can be overcome by engineering the microstructures of the cathodes. Microstructurally engineered cathodes with rod-shaped primary particles aligned radially exhibited higher capacity by reducing kinetic hindrance at the end of discharge and improved cycling stability by suppressing microcrack formation. Pouch-type full-cell tests under practical conditions confirmed the effectiveness of the modified microstructure, underscoring the role of the cathode microstructure in determining ASSB performance. Overall, this study provides insights into the design of layered cathode materials, guiding future development of high-energy-density ASSBs with long battery lives.