Constructing High-Performance Lithium-Rich Manganese-Based Cathode Materials for Lithium-Ion Batteries by Surface Modification Coupling Doping Strategy

Layered lithium-rich manganese oxide cathode materials (LMRO), characterized by their high theoretical specific capacity, are auspicious for lithium-ion batteries. However, low initial Coulombic efficiency, poor cycling stability, and inadequate rate capability remain significant challenges in practical applications. Herein, a strategy of surface modification coupling ion doping is developed to improve both the rate performance and cycling stability of LMRO. On the one hand, MXene was oxidized into a TiO 2 coating layer for LMRO, simultaneously inducing the generation of a spinel phase on the LMRO surface. The in situ formed spinel phase provides a three-dimensional diffusion pathway for lithium ions, which greatly improves the initial Coulombic efficiency (ICE) and rate performance. On the other hand, aluminum doping forms a strong Al–O bond, which improves the cycling stability of LNCMAO. The obtained MXT@LNCMAO cathode materials displayed a high discharge specific capacity of 270.0 mAh/g and a commendable initial Coulombic efficiency of 91.2% at a 0.2 C current density. After 400 cycles tested at 5 C, the capacity retention rate stood at 86.1%. Therefore, the MXene surface modification coupling doping strategy has shown promising competence in enhancing the electrochemical performance, which may become a general strategy to improve the performance of lithium-ion batteries.