Rate Performance Modification of a Lithium-Rich Manganese-Based Material through Surface Self-Doping and Coating Strategies

Lithium-rich manganese-based materials are currently considered to be highly promising cathode materials for next-generation lithium-ion batteries due to their high specific capacity (>250 mA h g^-1) and low cost. A key challenge for the commercialization of these lithium-rich manganese-based materials is their poor rate performance, which is caused by the low electronic conductivity and increasing interface charge transfer resistance produced by the side reaction during the cycling procedure. In this work, we try to improve the rate performance of a lithium-rich manganese-based material Li_1.2Mn_0.54Co_0.13Ni_0.13O₂ using a collaborative approach with Co-doping and Na_xCoO₂-coating methods. Cobalt doping can improve the electronic conductivity, and Na_xCoO₂ coating provides a convenient lithium-ion diffusion channel and moderately alleviates the inevitable decrease in cycling stability caused by cobalt doping. Under the synergistic effect of these two modification strategies, the surface and internal dynamics of the Li_1.2Mn_0.54Co_0.13Ni_0.13O₂ material are enhanced and its rate performance is considerably improved without decay of the cycle stability.