Research progress of lithium-rich solid-state batteries: challenges and perspectives

Cathode materials hold a crucial position in enhancing the energy density and capacity of lithium-ion batteries (LIBs). Notably, lithium-rich manganese oxide (LRMO) cathode materials boast high density and high capacity (exceeding 250 mAh g^-1), thus serving as a key element for the further commercialization of LIBs. Nevertheless, LRMO is prone to potential decay and poor cycling performance due to uncontrollable phase transition, so it is urgent to explore the corresponding modification approaches. Compared to LIBs based on liquid organic ester/ether electrolytes, all-solid-state lithium-ion batteries (ASSLIBs) have emerged as promising contenders due to their superior safety, compliance with modern requirements, and longer service life. This review systematically summarizes the challenges and modification strategies of LRMO for ASSLIBs, covering surface coating, interface engineering, lattice doping, and synergistic approaches. The structure-activity mechanisms underlying the improved electrochemical performance are thoroughly analyzed, and the intrinsic correlations between different modification strategies and structural stability as well as interfacial compatibility of LRMO are systematically clarified. Therefore, this review can serve as a reference for promoting the commercialization of high-performance LRMO cathode materials in ASSLIBs.