Construction of high chemical and electrochemical compatible interface of Li-rich Mn-based cathode for all-solid-state lithium batteries

Li-rich Mn-based oxides (LRMO) are of great significance in achieving high energy density all-solid-state lithium batteries (ASSLBs), owing to their high theoretical capacity and high operation voltage. Unfortunately, their practical application is hindered by severe interface degradation due to the chemical oxidation and electrochemical decomposition of solid electrolytes (SEs), driven by high-active oxygen and electron sources from LRMO. Herein, an interfacial modification strategy is proposed to stabilize the surface lattice oxygen of LRMO and reduce electronic conduction between LRMO and SEs, synergistically. Accordingly, the byproducts from chemical oxidation (InO − ) and electrochemical decomposition (LiCl − ) are largely suppressed, leading to superior interfacial transport with the lowest resistance. Consequently, the ASSLB achieves a high reversible capacity of 227.9 mA h g −1 at 0.1 C, a cycling stability of 90.1% capacity retention after 200 cycles at 0.1 C, and a superior rate capability with a capacity of 81.7 mA h g −1 at 3.0 C. This study enriches the fundamental understanding of LRMO/SEs interfacial evolution during the electrochemical cycling and the proposed interfacial modification strategy benefits the future design of Li-rich compounds for ASSLBs.