Two-step synthesis of nanocomposite LiFePO4/C cathode materials for lithium ion batteries

A two-step method is developed for the preparation of nanocomposite LiFePO4/C cathode materials for lithium ion batteries. Water is used as a solvent in the sintering process, with Fe(CH3COO)(2)center dot 4H(2)O and H3PO4 as the raw materials and citric acid as the carbon source. The synthesis of the resultant grain-size precursor is then performed at 700 degrees C for 1 h in order to obtain a lithiation reaction precursor via ball milling. The crystal structure and morphology of the samples are characterized using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The electrochemical properties of the material are assessed using charge-discharge and cyclic voltammetry testing. Based on the test results, the discharge capacity of LiFePO4/C reaches 163.3 mA h g(-1) in the first cycle, which is close to the theoretical value (170 mA h g(-1)). After 50 charge-discharge cycles, a capacity of 154.4 mA h g(-1) is obtained. The capacity retention ratio is 94.5%.