Electrochemical performance of LiFePO4/(C+Fe2P) composite cathode material synthesized by sol-gel method

A LiFePO4/(C+Fe2P) composite cathode material was prepared by a sol-gel method using Fe(NO3)3·9H2O,LiAc·H2O,NH4H2PO4 and citric acid as raw materials,and the physical properties and electrochemical performance of the composite cathode material were investigated by X-ray diffractometry(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM) and electrochemical tests.The Fe2P content,morphology and electrochemical performance of LiFePO4/(C+Fe2P) composite depend on the calcination temperature.The optimized LiFePO4/(C+Fe2P) composite is prepared at 650 °C and the optimized composite exhibits sphere-like morphology with porous structure and Fe2P content of about 3.2%(mass fraction).The discharge capacity of the optimized LiFePO4/(C+Fe2P) at 0.1C is 156 and 161 mA·h/g at 25 and 55 °C,respectively,and the corresponding capacity retentions are 96% after 30 cycles;while the capacity at 1C is 142 and 149 mA·h/g at 25 and 55 °C,respectively,and the capacity still remains 135 and 142 mA·h/g after 30 cycles at 25 and 55 °C,respectively.