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

A LiFePO 4 /(C+Fe 2 P) composite cathode material was prepared by a sol-gel method using Fe(NO 3 ) 3 ·9H 2 O, LiAc·H 2 O, NH 4 H 2 PO 4 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 Fe 2 P content, morphology and electrochemical performance of LiFePO 4 /(C+Fe 2 P) composite depend on the calcination temperature. The optimized LiFePO 4 /(C+Fe 2 P) composite is prepared at 650 °C and the optimized composite exhibits sphere-like morphology with porous structure and Fe 2 P content of about 3.2% (mass fraction). The discharge capacity of the optimized LiFePO 4 /(C+Fe 2 P) at 0.1 C 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 1 C 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.