Preparation And Modification LiFePO₄ Of Anode Material

Because of the excellent cyclying property, high safety performance and good thermal stability, LiFePO₄ material has attracted extensive attention. People have been trying to improve the poor electrical. In this article, we prepared the FePO4 as the precursor by hydrothermal method. LiFePO₄/C was synthesized by carbon-thermal reduction method. And then the performance of LiFePO₄/C was improved by doping. At last, the pHysical and electrochemical properties of the materials were investigated.LiFePO₄/C materials were prepared by a two-step preparation. The structure and morpHology of the materials were characterized by XRD, SEM, TG/DSC, IR and so on.We study the influence of hydrothermal time, solution concentration, pH value, Fe/P, and calcination temperature on the structure and morpHology of FePO4 precursor. And then we obtain the optimum synthesis process. On the basis of the best synthesis process,grapHeme was doped into the FePO4 precursor to improve the electrical conductivity of LiFePO₄/C which was synthesized with FePO4 as the raw material. Electrochemical tests of the different Li/Fe ratio materials showed that when the ratio of Li/Fe is 1.02, the electrochemical property of the material was the best.Carbon coating had improved the conductivity of the material, resulting in the LiFePO₄/C materials with better electrochemical performance. The initial discharge specific capacity was 130 mAh·g-1 at 0.1 C rate, the discharge specific capacity decreased to 100 mAh·g-1 at the 5 C rate, and the discharge specific capacity decreased to 80 mAh·g-1 at the 10C rate. The material had good cycling stability. The discharge capacities of material at different rates were all significantly improved after dopeing grapHene.