Research on a New Industrialized Preparation Method for Lithium Iron Phosphate with Balanced Compaction Density and Capacity

本研究通过系统调控烧结温度、体系理论Fe/P，结合锂补偿策略，提升传统工业化磷酸铁锂(LiFePO₄)的压实密度与电化学性能。实验表明：在765℃烧结温度及初始Fe/P为0.968时，材料的压实密度及电化学性能实现性能平衡，0.1 C容量161.5 mAh/g，烧结压实密度2.32 g/cm3。通过添加磷酸调整体系理论Fe/P，烧结压实密度提升至2.47 g/cm3，但过量磷酸导致非活性相生成，界面阻抗增加，致使容量显著下降，选择结合补锂挥发损失，以抑制晶格缺陷，改善后1 C容量提升至149.1 mAh/g。在本研究中，提出了一种工业化制备路径，实现压实密度与高容量的兼容。该研究为高能量密度动力电池用LiFePO4的开发提供了理论依据与工艺指导。This study systematically regulated the sintering temperature and the theoretical Fe/P ratio of the system, combined with a lithium compensation strategy, to enhance the compaction density and electrochemical performance of traditional industrialized lithium iron phosphate (LiFePO₄). The experiments demonstrated that at a sintering temperature of 765˚C and an initial Fe/P ratio of 0.968, the material achieved a balance in compaction density and electrochemical performance, with a capacity of 161.5 mAh/g at 0.1 C and a sintering compaction density of 2.32 g/cm3. By adjusting the theoretical Fe/P ratio of the system through the addition of phosphoric acid, the sintering compaction density was increased to 2.47 g/cm3. However, the excess phosphoric acid led to the formation of inactive phases, increased interface impedance, and a significant decrease in capacity. By combining lithium compensation to offset the loss due to volatilization, lattice defects were suppressed, and the 1 C capacity was improved to 149.1 mAh/g. In this study, an industrialized preparation path was proposed to achieve compatibility between compaction density and high capacity. This research provides a theoretical basis and process guidance for the development of LiFePO4 for high-energy-density power batteries.