Preparation of carbon coated LiFePO4 by a combination of spray pyrolysis with planetary ball-milling followed by heat treatment and their electrochemical properties

Carbon coated LiFePO4 could be successfully prepared by a combination of spray pyrolysis (SP) with planetary ball-milling (BM) followed by heat treatment at 500 °C. SEM and TEM observations revealed that the carbon coated LiFePO4 were much smaller in size than the bare LiFePO4 prepared by the SP followed by heat treatment at 600 °C and the ball-milled bare LiFePO4 prepared by the combination of SP with BM followed by heat treatment at 500 °C. Furthermore, TEM observations also suggested that conductive carbon could be distributed well on the surface of LiFePO4. The electrochemical measurements demonstrated that the carbon coated LiFePO4 could deliver better battery performance in terms of the discharge capacity, cycling stability and rate capability than the bare LiFePO4 and the ball-milled bare LiFePO4. It exhibited first-discharge capacities of 158 mAh g− 1 at 0.1C and 114 mAh g− 1 at 5C with excellent cycle performances at 25 °C. The cell tested at 60 °C delivered the theoretical capacity (170 mAh g− 1) at 0.1C and 78% (133 mAh g− 1) of theoretical capacity at 5C, respectively.