The precursor of FePO₄·2H₂O is prepared by a liquid phase conversion method with low-cost fine Fe₃O₄ ore powder from magnetite flotation, and the LiFePO₄/C is synthesized by sanding and spray followed by roasting technology. By controlling the excess coefficient of phosphate to Fe, the influence on the degree of chemical reaction and the preferred orientation of the precursor of nano sheet FePO₄·2H₂O on the (020) face is investigated. The results indicate that when the mole of phosphate is 2.5 times that of iron, the thickness of the FePO₄·2H₂O precursor nanosheet is the thinnest, resulting in the synthesis of LiFePO₄/C materials with the smallest primary particles and the best electrochemical properties. It can be observed that the specific discharge capacity of the as-prepared LiFePO₄/C can reach 150.5 mAh/g at 1 C, and the capacity retention rate is still over 96% after 450 cycles at 2 C. At the same time, the Re-LFP/C-2 synthesized with FePO₄·2H₂O by recycling H₃PO₄ mother liquor can achieve the same excellent electrochemical performance as the LFP/C-2 synthesized with fresh H₃PO₄. It is demonstrated that this route has promising development prospects and is easily scalable. At the same time, this synthetic route is cheaper to synthesize and produces less wastewater, which provides a basis for exploring the green, efficient, and low-cost synthesis route of LiFePO₄/C.

中文翻译：

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通过高效路线制备 LiFePO4 正极材料的纳米磷酸铁片


以磁铁矿浮选低成本的细 Fe₃O₄ 矿粉为原料，采用液相转化法制备了 FePO₄·2H₂O 的前驱体，并通过砂磨和喷雾后焙烧技术合成了 LiFePO₄/C。通过控制磷酸盐对 Fe 的过量系数，研究了纳米片 FePO₄·2H₂O 在 （020） 面上化学反应程度和优选取向的影响。结果表明，当磷酸盐摩尔数是铁的 2.5 倍时，FePO₄·2H₂O 前驱体纳米片的厚度最薄，从而合成了具有最小初级颗粒和最佳电化学性能的 LiFePO₄/C 材料。可以观察到，所制备的 LiFePO₄/C 的比放电容量在 1 C 下可达 150.5 mAh/g，在 2 C 下循环 450 次后容量保持率仍超过 96%。同时，通过回收 H₃PO₄ 母液合成的 FePO₄·2H₂O 合成的 Re-LFP/C-2 可以达到与新鲜 H₃PO₄ 合成的 LFP/C-2 相同的优异电化学性能。结果表明，这条路线具有广阔的发展前景，并且易于扩展。同时，这种合成路线合成成本更低，产生的废水更少，为探索 LiFePO₄/C 绿色、高效、低成本的合成路线提供了基础。