Maximizing Areal Capacity in All-Solid-State Li-Ion Batteries Using Single Crystalline Ni-Rich Cathodes and Bromide-Based Argyrodite Solid Electrolytes Under Optimized Stack Pressure

All-solid-state lithium-ion batteries (ASSLBs) are a promising next-generation energy storage technology for their enhanced safety and high energy density. In this study, we develop high-performance ASSLBs utilizing a Ni-rich single-crystalline NCM811 (SC-NCM811) cathode and a Li6PS5Br argyrodite solid electrolyte. By optimizing the cathode material and stack pressure, we demonstrate an exceptional areal capacity exceeding 4 mAh/cm2 with a high cathode loading of ∼21 mg/cm2. Electrochemical performance comparisons between SC-NCM811 and polycrystalline NCM811 (PC-NCM811) reveal the superior capacity retention and rate performance of SC-NCM811-based ASSLBs, particularly at an optimized stack pressure. Our findings underscore the potential of SC-NCM811 as a highly efficient cathode material for next-generation ASSLBs, offering both increased energy density and operational safety. This work highlights the importance of cathode engineering and pressure optimization in advancing the implementation of ASSLBs.