LiAlO2-coated LiNi0.8Co0.1Mn0.1O2 and chlorine-rich argyrodite enabling high-performance all-solid-state lithium batteries at suitable stack pressure

All-solid-state lithium batteries (ASSLBs), which are consisted of Li5.5PS4.5Cl1.5 electrolyte, metal lithium anode and LiNi0.8Mn0.1Co0.1O2 (NCM811) cathode, are speculated as a promising next generation energy storage system. However, the unstable oxide cathode/sulfide-based electrolyte interface and the dendrite formation in sulfide electrolyte using the lithium metal anode hinder severely commercialization of the ASSLBs. In this work, the dendrite formation in sulfide electrolyte is investigated in lithium symmetric cell by varying the stack pressure (3, 6, 12, 24 MPa) during uniaxial pressing, and uniformly nanosized LiAlO2 buffer layer was carefully coated on NCM811 electrode (LiAlO2@NCM811) to improve the cathode/electrolyte interface stability. The result shows that lithium symmetrical cell has a steady voltage evolution over 400 h under 6 MPa stacking pressure, and the assembled LiAlO2@NCM811/Li5.5PS4.5Cl1.5/Li battery under the stack pressure of 6 MPa exhibits large initial discharge specific capacity and excellent cycling stability at 0.05 C and 25 °C. The feasibility of using the lithium metal anode in all-solid-state batteries (ASSBs) under suitable stack pressure combined with uniformly nanosized LiAlO2 buffer layer coated on NCM811 electrode supply a facile and effective measures for constructing ASSLBs with high energy density and high safety.