Effects of Citric Acid Content on the Morphology and Electrochemical Performance of LiFePO_4/C Composite Cathode Materials

The LiFePO4/ C composites with different morphology were prepared by a combination of hydrothermal method and calcination process,and the influences of citric acid content on their morphology and electrochemical performances were investigated. The results indicate that the addition of citric acid has a significant effect on the morphology of the LiFePO4/ C composites. Controlling the morphology of LiFePO4/ C composites by adding citric acid can greatly improve the electrochemical performance of the LiFePO4/ C composites. When the molar ratio of citric acid and LiFePO4 is 1∶ 2,the LiFePO4/ C composites are nano-sheets,and have the minimum particles size and the maximum specific surface area. Their discharge capacities are 160. 3 mA ·h·g- 1at 0. 1 C and 130. 9 mA ·h·g- 1at 5 C.