类球形低硫磷酸铁的制备技术研究

磷酸铁(FePO4)是锂电池正极材料磷酸铁锂(LiFePO4)的核心前驱体,FePO4形貌及硫含量对合成的LiFePO4材料性能有重要影响。为得到类球形低硫FePO4产品,在传统液相沉淀法技术基础上做了改进优化,添加十六烷基三甲基溴化铵(CTAB)作为形貌助剂提高产品球形度,添加氨水作为配体形成磷酸铁铵配合物改善结晶过程,降低产品硫含量。结果表明:所制备的FePO4产品硫质量分数低,达到2.6×10^-5,形貌为均一的微米类球形颗粒,D50=11.4μm,振实密度达到1.22 g/cm^3,有望成为制备高压实密度LiFePO4材料的核心前驱体。

Study of the method for the preparation of spherical-like and low sulfur FePO4

FePO₄ is the core precursor of LiFePO₄.The morphology and sulfur content of FePO₄ products have important ef-fects on the properties of the synthesized LiFePO₄ materials.To obtain spherical-like and low-sulfur FePO₄ products,the tradi-tional liquid phase precipitation method was improved and optimized.Adding CTAB as a morphology additive to improve the sphericity of the products,and adding ammonia water as a ligand to form the ammonium ferric phosphate complex in order to improve the crystallization process and reduce the sulfur content of the product.The results showed that the prepared FePO₄ products have low sulfur content of up to 2.6×10 ^-5 and were homogeneous micro-spherical-like particles with D₅₀=11.4 μm and tap density of 1.22 g/cm ³ that are expected to be the core precursors for the preparation of high compacted deasity LiFePO₄ materials.