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

LiFePO 4 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 LiFePO 4 has the greatest improvement in electronic conductivity and Li + diffusivity. However, the rate performance of carbon-coated LiFePO 4 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 LiFePO 4, thus, enabling its wider application.