前驱体二水磷酸铁对磷酸铁锂电化学性能的影响

摘要

以钛白生产副产物七水硫酸亚铁为铁源,工业磷酸二氢铵为磷源,双氧水为氧化剂,采用共沉淀法合成了不同粒径和形貌的二水磷酸铁,并以此为前驱体,通过碳热还原法制备了粒径不同的LiFePO4/C正极材料.经过对样品进行X射线衍射(XRD)、扫描电镜(SEM)以及恒电流充放电测试,研究了二水磷酸铁及LiFePO4/C的结构、形貌以及电化学性能.结果表明,以较细的二水磷酸铁为铁源,制备得到的LiFePO4/C颗粒较细,且具有更优异的电化学性能.0.1、0.5、1、2、5、10C放电比容量分别为154、148、144、140、130、120 mA· h/g.%The precursor, FePO4·2H2O with different particle sizes and morphologies was syhthesized by co-precipitation method with FeSO4·7H2O by-produced from the production of titanium dioxide as the iron source, industrial NH4H2PO4 as the phosphorus source, and with H2O2 as the oxidant.LiFePC/C cathode material was prepared through carbon thermal reduction technology with as-prepared FePO4·2H2O as iron source.The structure, morphology, and electrochemical properties of FePO4· 2H2O and IiFePO4/C samples were characterized by XRD,SEM,and galvanostatic charge-discharge tests.Results showed that LiFeP(VC had much smaller particle size and superior electrochemical performance when the FePO4·2H2O with smaller particle size was used as iron source.The initial discharge capacity of the sample was 154,148,144,140,130,120 mA·h/g at 0.1,0.5,1,2,5 ,10 C rates, respectively.