A Novel Strategy for the Synthesis of Fe(3)(PO(4))(2) Using Fe–P Waste Slag and CO(2) Followed by Its Use as the Precursor for LiFePO(4) Preparation

[Image: see text] A novel method whose starting materials was Fe–P waste slag and CO(2) using a closed-loop carbon and energy cycle to synthesize LiFePO(4)/C materials was proposed recently. In the first step, Fe–P slag was calcinated in a CO(2) atmosphere to manufacture Fe(3)(PO(4))(2), in which the solid products were tested by XRD (X-ray diffraction) analysis and the gaseous products were analyzed by the gas detection method. In the second step, as-synthesized Fe(3)(PO(4))(2) was further used as the Fe and P source to manufacture LiFePO(4)/C materials. Also, the influence of the preparation conditions of Fe(3)(PO(4))(2), including calcination time and calcination temperature, on the energy storage properties of as-obtained LiFePO(4)/C was investigated. It was found that the LiFePO(4)/C materials, which was synthesized from Fe(3)(PO(4))(2) obtained by calcining Fe–P waste slag at 800 °C for 10 h in CO(2), exhibited a higher capacity, better reversibility, and lower polarization than other samples. The discharge capacity of as-obtained LiFePO(4)/C can reach 145 mAh/g at 0.1 C current rate. This work puts forward an environment-friendly method of manufacturing LiFePO(4)/C cathode materials, which has a closed-loop carbon and energy cycle.