Excellent electrochemical performance europium-doped LiFePO4 cathode material derived from acid-washed iron red

In order to better recycle and reuse metal ions in metallurgical industrial waste and reduce the production cost of lithium-ion batteries (LIBs). In this paper, carbon-coated LiFePO₄/C cathode materials are synthesized through the carbothermal reduction method using acid-washed iron red as raw material. In order to make LiFePO₄/C exhibit satisfactory electrical properties, the rare earth element Eu is doped in the Fe position, and the doping amount is optimized. The influence of the double coupling effect of coating and doping on the structure and properties of LiFePO₄ cathode materials is systematically discussed. The local XRD results of the doped samples show that the diffraction peaks of the doped samples move to the small angle grain boundaries, and the lattice spacing of the materials increases, which is due to the large radius of Eu ions. The experimental results show that the dual coupling of carbon coating and ion doping can improve the conductivity of LiFePO₄ cathode materials and improve its electrochemical performance. When the doping amount of Eu is 2%, the electrochemical performance of LiFe_0.98Eu_0.02PO₄/C cathode material is the best. The initial charge–discharge capacity of 153/144.4 mAh·g⁻¹ can be obtained at 0.5C, and a discharge capacity of 143.2 mAh·g⁻¹ remains after 50 cycles. The exploration of this experiment provides a reasonable solution for slowing down the pollution of metallurgical waste to the environment and reducing the production cost of LIBs.