Preparation of FePO4 from leaching liquor of Fe P waste slag and its application in lithium ions batteries

By employing FePO4, LiOH·H2O, and sucrose as starting materials, LiFePO4/C cathode material is produced through a carbothermal reduction method. The FePO4 precursor is synthesized via a straightforward chemical precipitation method with the hydrochloric acid leaching liquor from FeP waste slag as a source of Fe and P. This study explores the impact of various precipitants, namely, Na2CO3, NaOH, and NH3·H2O (FP-1, FP-2, FP-3) on the crystal phase, morphology, and particle size microstructure of the FePO4 using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and particle size analyzer. The results show that all the prepared materials are pure phase and composed of irregular nanoparticles. The LiFePO4 sample, synthesized with FP-1 as a precursor, demonstrates superior electrochemical properties as a cathode material in the field of lithium-ion batteries, indicating great application potential. At various current rates (0.1, 0.2, 0.5, 1, 2, 5, and 10C), the discharge capacities are 140.8, 138.9, 138.0, 134.6, 128.6105.5, and 61.8 mAh g−1. After 100 cycles at the specified rates, a 100% recovery rate is achieved at 1C. This study introduces a pioneering and efficient approach for utilizing the FeP waste slag, offering substantial societal and economic advantages that contribute to the sustainable development of industries.