Significant Enhancement of the Capacity and Cycling Stability of Lithium-Rich Manganese-Based Layered Cathode Materials via Molybdenum Surface Modification

Lithium-rich manganese-based layered cathode materials are considered to be one of the best options for next-generation lithium-ion batteries, owing to their ultra-high specific capacity (>250 mAh·g(−1)) and platform voltage. However, their poor cycling stability, caused by the release of lattice oxygen as well as the electrode/electrolyte side reactions accompanying complex phase transformation, makes it difficult to use this material in practical applications. In this work, we suggest a molybdenum surface modification strategy to improve the electrochemical performance of Li(1.2)Mn(0.54)Ni(0.13)Co(0.13)O(2). The Mo-modified Li(1.2)Mn(0.54)Ni(0.13)Co(0.13)O(2) material exhibits an enhanced discharge specific capacity of up to 290.5 mAh·g(−1) (20 mA·g(−1)) and a capacity retention rate of 82% (300 cycles at 200 mA·g(−1)), compared with 261.2 mAh·g(−1) and a 70% retention rate for the material without Mo modification. The significantly enhanced performance of the modified material can be ascribed to the formation of a Mo-compound-involved nanolayer on the surface of the materials, which effectively lessens the electrolyte corrosion of the cathode, as well as the activation of Mo(6+) towards Ni(2+)/Ni(4+) redox couples and the pre-activation of a Mo compound. This study offers a facile and effective strategy to address the poor cyclability of lithium-rich manganese-based layered cathode materials.