Recent developments and challenges of Li-rich Mn-based cathode materials for high-energy lithium-ion batteries

Li-rich Mn-based layered oxide cathodes (LLOs), delivering high specific capacity of >300 mAh g−1 and maximum energy density of >1000 Wh kg−1, are deemed to be one of the most promising cathode candidates for next-generation lithium-ion batteries over 350 Wh kg−1 at the full cell level. However, the practical application of LLOs is still hindered by two main challenges: microcosmic material drawbacks (structural instability, poor diffusion kinetics, etc.) and thus induced macroscopic decay of electrochemical performance (low initial Coulombic efficiency, fast capacity/voltage decay, etc.). In this review, we summarize the current developments of LLOs in the structure, corresponding reaction mechanisms, and electrochemical performances, discuss the relationship between inherent material drawbacks and external performance decay, as well as summarize the performance degradation mechanisms and addressing strategies to provide guidance and perspectives for future LLOs research.