不同有机-水混合溶剂的Li3V2（PO4）3/C合成及其性能

以有机-水为混合溶剂,采用溶胶-凝胶法制备锂离子电池正极材料Li3V2(PO4)3/C。通过X射线衍射(XRD)、扫描电镜(SEM)、恒流充放电以及循环伏安(CV)测试等方法,研究产物的结构形貌及电化学性能。结果表明:溶剂对材料的晶型结构没有影响,对颗粒的形貌影响较大;以1,2-丙二醇-水为溶剂的样品呈薄片状和针状;在3.0～4.5 V电压范围内,Li3V2(PO4)3/C的0.1C首次放电比容量为132.89 mA.h/g,10C首次放电比容量达125.42 mA.h/g,循环700周后容量保持率为95.79%,具有良好的倍率性能与循环性能;而在3.0～4.8 V电压范围内倍率性能较差。

Synthesis and performance of Li3V2（PO4）3/C with different organic-water mixed solvents

The cathode material Li3V2(PO4)3/C was synthesized by sol-gel method using organic and water as mixed solvents.The structure,morphology and electrochemical performance of the synthesized cathode materials Li3V2(PO4)3/C were studied by X-ray diffractometry(XRD),scanning electron microscopy(SEM),charge-discharge tests and cycle voltammetry(CV).The results show that different solvents have no effect on the crystal structure of the samples,but have great impact on the morphology of the particles.The sample prepared by using 1,2-propylene glycol-water as the mixed solvent has a flake-like and needle-like shape,it exhibits an initial discharge capacity of 132.89 mA-h/g at 0.1C rate in the voltage range of 3.0-4.5 V;the initial discharge capacity is as high as 125.42 mA-h/g when discharging at 10C,which keeps a capacity retention of 95.79% after the 700th cycle,indicating good rate and cycling performance;however,it exhibits a bad rate performance in the voltage range of 3.0-4.8 V.