前驱体制备工艺条件对FePO_4·2H_2O和LiFePO_4性能的影响  

Effect of precursor preparation condition on FePO_4·2H_2O and performance of LiFePO_4

作　　者：董虹[1] 叶红齐[1] 韩凯[1] 刘辉[1] 杜瑜敏[1] 覃涛[1] 郝梦秋[1] 刘贡钢[1] 

机构地区：[1]中南大学化学化工学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2014年第3期695-702,共8页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(21276284)

摘　　要：以九水合硝酸铁(Fe(NO3)3·9H2O)和二水合磷酸二氢钠(NaH2PO4·2H2O)为原料,采用反加沉淀法制备FePO4·2H2O前驱体。将FePO4·2H2O,Li2CO3和葡萄糖混合均匀后经高温固相烧结得到LiFePO4/C锂离子正极材料。考察前驱体反应温度、溶液的pH和滴加速度对FePO4·2H2O颗粒形貌、粒径以及LiFePO4的电化学性能的影响。采用扫描电镜(SEM)和激光粒度分析仪(LPSA)对样品的形貌和粒径进行表征。实验结果表明:FePO4·2H2O颗粒的粒径和分散性影响LiFePO4/C锂离子正极材料的电化学性能,粒径较小且均匀分散的前驱体制得的LiFePO4的电化学性能较好。优化条件下制得的前驱体颗粒为片状,平均粒径为1.08μm。相应的LiFePO4在0.1C充放电倍率下的首轮充电容量为159.3 mA·h/g,放电容量为159.0 mA·h/g,首次充放电效率为99.8%。材料表现出良好的循环倍率性能和结构稳定性。s： Precipitation of negative dropping was adopted to prepare FePO4·2H2O precursor. After high-temperature calcination, LiFePO4/C cathode materials were synthesized by carbothermal reduction. Experiments were presented to investigate the effect of reaction temperature, solution pH and dropping speed on FePO4·2H2O and LiFePO4/C. The morphology and particle size of samples were characterized by scanning electron microscopy （SEM） and laser particle size analyzer （LPSA）. The results show that particle size and dispersity of FePO4·2H2O influence the electrochemistry properties of LiFePO4/C. LiFePO4/C prepared by FePO4·2H2O with small particle size and good dispersion has good electrochemical performance. Under optimum conditions, mean particle size of FePO4·2H2O is 1.08 μm. The first charge and discharge capacity of LiFePO4 are 159.3 mA.h/g and 159.0 mA.h/g at 0.1C rate. The first charge-discharge efficiency is 99.8%. The cathode materials exhibite good cycling performance, rate capability and structure stability.

关 键 词：反加沉淀法 FePO4·2H2O LIFEPO4 

分 类 号：TQ152[化学工程—电化学工业] O61[理学—无机化学]