Improved electrochemical performance of LiFePO4/carbon cathode for lithium-ion batteries

LiFePO4/carbon (LFP/C) composites with different carbon contents are obtained through a carbothermic reduction process using glucose as carbon source. The effect of carbon content on the performance of LFP is investigated through structure and electrochemical characterization analysis. It is obvious that LFP/C composites significantly enhance the electrochemical performance compared with the unmodified LFP as the carbon content increases. In particular, LFP/C with 15% carbon content (LFP/C-15) exhibits the highest initial discharge specific capacity and the most superior capacity retention rate, with a discharge capacity of 160.7 mAh g(-1) and a capacity retention rate of 82.1% after 100 cycles at 0.1 C. Moreover, the discharge capacity is already very close to the theoretical specific capacity of LiFePO4 (170 mAh g(-1)). However, when the carbon content reaches 20%, the electrochemical performance decreases instead, indicating that excessive carbon content has the opposite effect on the improvement of material performance. Hence, the carbon content plays a crucial role in the future improvement of the material properties.