Enabling superior electrochemical performance of NCA cathode in Li_5.5PS_4.5Cl_1.5-based solid-state batteries with a dual-electrolyte layer

LiNi_0.8Co_0.15Al_0.05O₂ (NCA) is a promising cathode for sulfide-based solid-state lithium batteries (ASSLBs) profiting from its high specific capacity and voltage plateau, which yielding high energy density. However, the inferior interfacial stability between the bare NCA and sulfides limits its electrochemical performance. Hereien, the dual-electrolyte layer is proposed to mitigate this effect and enhance the battery performances of NCA-based ASSLIBs. The Li₃InCl₆ wih high conductivity and excellent electrochemcial stability act both as an ion additives to promote Li-ion diffusion across the interface in the cathode and as a buffer layer between the cathode layer and the solid electrolyte layer to avoid side reactions and improve the interface stability. The corresponding battery exhibits high discharge capacities and superior cyclabilities at both room and elevated temperatures. It exhibits discharge performance of 237.04 and 216.07 mAh/g at 0.1 and 0.5 C, respectively, when cycled at 60 °C, and sustains 95.9% of the capacity after 100 cycles at 0.5 C. The work demonstrates a simple strategy to ensure the superior performances of NCA in sulfide-based ASSLBs.