Recent Progress and Challenges of Li-Rich Mn-Based Cathode Materials for Solid-State Lithium-Ion Batteries

Li-rich Mn-based (LRM) cathode materials, characterized by their high specific capacity (>250 mAh g⁻¹) and cost-effectiveness, represent promising candidates for next-generation lithium-ion batteries. However, their commercial application is hindered by rapid capacity degradation and voltage fading, which can be attributed to transition metal migration, lattice oxygen release, and the toxicity of Mn ions to the anode solid electrolyte interphase (SEI). Recently, the application of LRM cathode in all-solid-state batteries (ASSBs) has garnered significant interest, as this approach eliminates the liquid electrolyte, thereby suppressing transition metal crosstalk and solid–liquid interfacial side reactions. This review first examines the historical development, crystal structure, and mechanisms underlying the high capacity of LRM cathode materials. It then introduces the current challenges facing LRM cathode and the associated degradation mechanisms and proposes solutions to these issues. Additionally, it summarizes recent research on LRM materials in ASSBs and suggests strategies for improvement. Finally, the review discusses future research directions for LRM cathode materials, including optimized material design, bulk doping, surface coating, developing novel solid electrolytes, and interface engineering. This review aims to provide further insights and new perspectives on applying LRM cathode materials in ASSBs.