Polyvinylpyrrolidone-assisted synthesis of microscale C-LiFePO4 with high tap density as positive electrode materials for lithium batteries

Carbon-coated LiFePO4 (C-LiFePO4) with micron particle size (6 μm) and high tap density (1.6 g cm−3) was prepared from spherical FePO4·2H2O powder via the co-precipitation method. The C-LiFePO4 powder was calcined at temperatures between 650 and 800 °C. The 6 μm C-LiFePO4 prepared at 800 °C exhibited an excellent rate capability, delivering 150 mAh g−1 on discharge at the 0.1 C-rate and 108 mAh g−1 at the 5 C-rate. The volumetric capacity of the 6 μm C-LiFePO4 corresponded to 225 mAh cm−3, since the large secondary particles (6 μm) C-LiFePO4 sufficiently allowed tight packing of the particles. The 6 μm C-LiFePO4 powder with high tap density makes an attractive positive electrode candidate for lithium-ion batteries designed for high energy density.