磷化渣制备磷酸铁锂及其性能研究

Study on preparation and performance of lithium iron phosphate material from phosphating slag

磷酸铁(FePO_(4))作为磷酸铁锂(LiFePO_(4))材料的前驱体,随着锂离子电池的发展引起了广泛的关注。磷化渣是磷化工业的副产物,含有大量的磷酸铁,将磷化渣提纯得到粗提纯FePO_(4),经水热重结晶得到亚微米-微米级前驱体FePO_(4),以碳热还原的手段得到LiFePO_(4)。研究了水热过程中十六烷基三甲基溴化铵(CTAB)添加量、pH对FePO_(4)粒度的影响。结构表征手段主要有XRD、SEM、LPS等,使用电化学工作站表征LiFePO_(4)材料的电化学性能。电化学表征结果表明,该材料具有较高的的首次充电比容量,接近磷酸铁锂的理论比容量,库仑效率达到93.51%,但高倍率下的充放电性能较差。

As the precursor of lithium iron phosphate(LiFePO_(4))materials,iron phosphate(FePO_(4))attracts widespread attention with the development of lithium ion batteries.Phosphating slag is a by-product of the phosphating industry and contains a large amount of iron phosphate.The phosphating slag is purified to obtain crudely purified FePO_(4),which is hydrothermally recrystallized to obtain sub-micron-micron precursor FePO_(4),and LiFePO_(4)is obtained by carbothermal reduction.The effects of CTAB addition and pH on the particle size of FePO_(4)in the hydrothermal process were studied.The structural characterization methods mainly include XRD,SEM,LPS,etc.The electrochemical workstation was used to characterize the electrochemical performance of LiFePO_(4)materials.The electrochemical characterization results show that the material has a high first charge specific capacity,which is close to the theoretical specific capacity of lithium iron phosphate,and the coulombic efficiency reaches 93.51%,but the charge and discharge performance at high rates is poor.