Effect of Na+ in situ doping on LiFePO4/C cathode material for lithium-ion batteries

Li1-XNaXFePO4 (X = 0, 0.01 or 0.05) composite cathode materials were synthesized by the simple solvothermal method. SEM images showed that Na doping had little effect on the morphology of particles, which provided a guarantee for its excellent electrochemical performance. Charge/discharge data revealed that an appropriate amount of doped Na could improve electrochemical performance. Li0.99Na0.01FePO4 showed excellent rate capacity and cycle stability, i.e., an extremely high keep in the capacity of 86.7% after 500 cycles at 10C, due to its ac facet morphology, larger lattice parameters in a and c, the enhanced electronic conductivity and Li-ion diffusion processes.