Preparation and characterization of high-rate and long-cycle LiFePO4/C nanocomposite as cathode material for lithium-ion battery

Olivine LiFePO4/C nanocomposite cathode materials with small-sized particles and a unique electrochemical performance were successfully prepared by a simple solid-state reaction using oxalic acid and citric acid as the chelating reagent and carbon source. The structure and electrochemical properties of the samples were investigated. The results show that LiFePO4/C nanocomposite with oxalic acid (oxalic acid: Fe2+= 0.75:1) and a small quantity of citric acid are single phase and deliver initial discharge capacity of 122.1 mAh/g at 1 C with little capacity loss up to 500 cycles at room temperature. The rate capability and cyclability are also outstanding at elevated temperature. When charged/discharged at 60 °C, this materials present excellent initial discharge capacity of 148.8 mAh/g at 1 C, 128.6 mAh/g at 5 C, and 115.0 mAh/g at 10 C, respectively. The extraordinarily high performance of LiFePO4/C cathode materials can be exploited suitably for practical lithium-ion batteries.