碳包覆Li3V2(PO4)3：溶胶-凝胶法合成及性能(英文)  

Carbon-coated Li_3V_2(PO_4)_3 Composite Cathode Material for Lithium-ion Batteries:Sol-gel Synthesis and Performance

作　　者：陈权启[1] 何伟春[1] 王建明[1] 唐征[1] 邵海波[1] 张鉴清[1] 

机构地区：[1]浙江大学化学系

出　　处：《无机化学学报》2008年第2期181-190,共10页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.50172041)资助项目

摘　　要：利用V2O5、LiOH·H2O、H2O2、NH4H2PO4与柠檬酸为原料,通过溶胶-凝胶法合成了碳包覆的Li3V2(PO4)3复合正极材料。采用XPS、XRD、SEM、TEM、拉曼光谱和电化学方法对材料的性能进行了研究。还研究了其结构与焙烧温度、样品电导率和电化学性能的关系。研究表明复合材料具有空间群为P21/n的单斜结构,表面包覆粗糙多孔的碳层。在800℃下制备的碳包覆样品的电子导电率高达9.81×10-5S·cm-1,约为高温固相氢气还原法制备的未包覆碳Li3V2(PO4)3的10000倍。测试结果表明碳包覆Li3V2(PO4)3的电化学性能远优于未包覆碳的样品。在3.0￣4.3V电压范围内,以0.1C和2C倍率充放电时,碳包覆的Li3V2(PO4)3具有高比容量(分别为128和109mAh·g-1)和优异的循环性能。A carbon-coated Li3V2（PO4）3 composite cathode material was synthesized by a sol-gel method using V2O5, LiOH·H2O, H2O2, NH4H2PO4 and citric acid as starting materials. Properties of the prepared composite material were investigated using XPS, XRD, SEM, Raman spectroscopy, TEM, and various electrochemical techniques. The relationship among structure, calcination temperature, electronic conductivity and the electrochemical performance of samples was also studied. The sample obtained had a monoclinic structure with a space group of P2 1/n and a rough and porous carbon surface layer. The electronic conductivity of the carbon-coated Li3V2（PO4）3 samples synthesized at 800 ℃ was about a factor of -10^4 higher than that of carbon-free Li3V2（PO4）3 prepared by solid-state hydrogen reducing reaction. The results show that the carbon-coated Li3V2（PO4）3 is superior in the electrochemical performance to the carbon-free sample. In the voltage range of 3.0-4.3 V, the carbon-coated Li3V2（PO4）3 synthesized at 800 ℃ displays large reversible capacities （128 mAh·g^-1 at 0.1C and 109 mAh·g^-1 at 2C, respectively） and excellent cyclic stability. The reason for the excellent electrochemical performance of the carbon coated Li3V2（PO4）3 is discussed.

关 键 词：磷酸钒锂 溶胶凝胶法 碳包覆 锂离子电池 

分 类 号：O614.111[理学—无机化学] O614.81[理学—化学]