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.
出处
《电源技术》
CAS
CSCD
北大核心
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)
