Li_3V_2(PO_4)_3/C复合正极材料的制备与性能  

Preparation and performance of Li_3V_2(PO_4)_3/C composite as cathode material for lithium ion battery

作　　者：刘素琴[1] 李世彩[1] 黄可龙[1] 

机构地区：[1]中南大学化学化工学院,湖南长沙410083

出　　处：《电源技术》2007年第6期446-449,共4页Chinese Journal of Power Sources

基　　金：国家自然科学基金(20376086);教育部博士点基金(20030533001)

摘　　要：以CH3COOLi、V2O5、NH4H2PO4和碳凝胶为原料,采用溶胶-凝胶法合成了锂离子蓄电池Li3V2(PO4)3/C复合正极材料。对其前驱体和产品采用热重-差热分析(TG-DTA)、X射线衍射(XRD)以及元素分析分别进行了表征。考察了掺杂碳含量对材料充放电性能及其高倍率循环性能的影响。样品C的首次放电比容量达到128.4mAh/g。样品B和C以0.2C充放120次后容量几乎没有衰竭;继续以1C充放电120次,其比容量仍基本恒定,比单一Li3V2(PO4)3材料具有更优良倍率性能和循环性能。交流阻抗测试表明碳掺杂可以形成碳包覆层,材料的电导率大幅提高,从而提高了材料的电化学性能。Composite cathode materials Li3V2 （PO4）3/C were synthesized by sol-gel method with CH3COOLi, V2O5, NH4H2PO4 and C gel as the raw materials. The precursor and product were characterized by differential thermal-analysis thermogravimetry （TG-DTA）, X-ray diffraction （XRD） measurements. Electrochemical properties of samples, changed by substitution of carbon, were investigated by charge-discharge cycle at different current densities. The first discharge capacity of the sample C was 128.4 mAh/g. After charge-discharge at 0.2 C rate for 120 cycles, the sample C retained a discharge specific capacity of 127.9 mAh/g, and its capacity seems to be constant during the later 120 cycles at 1 C rate, which showed a better cycle performance than pure materials of Li3V2（PO4）3. The results of electrochemical impedance spectroscopy （EIS） show that the coated carbon enhances the conductivity and electrochemical performance of materials.

关 键 词：锂离子蓄电池 复合材料 溶胶-凝胶 LI3V2(PO4)3 

分 类 号：TM912.9[电气工程—电力电子与电力传动]