Ameliorating the cycle stability of lithium-rich manganese-based cathodes via carbon coating for lithium-ion batteries

Lithium-rich manganese-based oxide (LMR) has emerged as one of the most promising cathode material candidates for high-energy-density lithium-ion batteries owing to its exceptional theoretical capacity. Nevertheless, its poor cycling stability and discharge voltage decay severely impede its practical commercialization. Herein, an ascorbic acid-mediated modification strategy was proposed to enable the construction of a carbon coating on the LMR surface. Based on theoretical and experimental analyses, the carbon coating not only could effectively suppress undesirable interfacial side reactions but also enhance electron transport kinetics so as to ameliorate discharge voltage decay and cycling stability. The optimized LMR (LMR-0.5) exhibited a high specific capacity of 269.1 mAh/g at 0.1 C (1 C defined as 300 mA/g) along with the initial Coulombic efficiency of 83.02%. After modification, the rate performance was significantly elevated and the LMR-0.5 maintained an impressive capacity retention of 91.7% after 500 cycles at 0.1 C, outperforming 78% of the unmodified LMR. This study clarified the introduced oxygen vacancies and the carbon coating layer in improving the electrochemical performance, providing valuable insights for advancing their development toward practical application in high-energy-density lithium-ion batteries.