Synergistic N/Mn Codoping Deagglomerate Carbon Coating of LiFePO4/C To Boost Electrochemical Performance

LiFePO₄ is widely used because of its high safety and cycle stability, but its inefficient electronic conductivity combined with sluggish Li⁺ diffusivity restricts its performance. To overcome this obstacle, applying a layer of conductive carbon onto the surface of LiFePO₄ has the greatest improvement in electronic conductivity and Li⁺ diffusivity. However, the rate performance of carbon-coated LiFePO₄ makes it difficult to meet the application requirements. Although nitrogen doping improves electrochemical performance by providing active sites and electronic conductivity, the N-doped carbon coating is prone to agglomeration, which causes a sharp decrease in capacity when the current rate increases. In this work, a synergistic N, Mn codoping strategy is implemented to overcome the aforementioned drawbacks by disrupting the large agglomeration of C-N bonds, improving the uniformity of the surface coating layer to enhance the completeness of the conductive network and increasing the number of Li⁺ diffusion channels, and thus accelerating the mass transfer rate under high-rate current. Consequently, this strategy effectively improves the rate capability (119 mA h g^-1 at 10 C) while maintaining excellent cycling performance (88% capacity retention over 600 cycles at 5 C). This work improves the rate of ion diffusion and the rate capability of micrometer-sized LiFePO₄, thus, enabling its wider application.