FePO4 was synthesized by rheological phase method using Fe2O3, NH4H2PO4 and H2NCONH2 as row materials. The influence of temperature on the synthesis process was investigated. Taking prepared FePO4 as iron source, LiFePO4 was also synthesized by rheological phase method. The structure and morphology of as prepared FePO4 and LiFePO4 were characterized by XRD and SEM, respectively. XRD results indicate that FePO4 is belong to the triclinic system, with a-quartz structure and LiFePO4 is belong to the orthorhombic system, with olivine structure. SEM results showed that the FePO4 particles were layered distribution, while the LiFePO4 particles seemed like spherical. Both of the particles were well dispersed, and the average particle sizes were about 2 μm. Electrochemical properties of the obtained LiFePO4 cathode material were investigated by galvanostatic charge-discharge test, cyclic voltammetry(CV) and alternating current(AC) impedance methodes, the initial discharge capacity could reach 163.4 mAh/g, indicating excellent electrochemical performance. All the above results indicated that the prepared iron phosphate is an ideal iron source for the synthesis of lithium-ion battery cathode material LiFePO4.%以Fe2O3、NH4H2PO4和H2NCONH2为原料,采用流变相法合成FePO4,探究了温度对其合成过程的影响.以此FePO4为铁源,再采用流变相法制备出正极材料LiFePO4.产物FePO4和LiFePO4的晶型、形貌分别通过XRD和SEM表征,XRD结果表明,FePO4属三斜晶系,具有α-石英结构,而LiFePO4属于斜方晶系,具有橄榄石结构；SEM结果表明,FePO4样品颗粒呈层状分布,LiFePO4晶体形貌为类球形,两者分散度良好,平均粒径均为2μm左右；对所得正极材料LiFePO4进行恒电流充放电测试,其初始放电容量达163.4 mAh/g.采用循环伏安、交流阻抗等对LiFePO4电化学性能表征,结果均显示其电化学性能良好.表明以Fe2O3为原料采用流变相法所得磷酸铁是合成锂离子电池正极材料磷酸铁锂的较理想的铁源.
展开▼
