锂离子电池正极材料Li_3V_2(PO_4)_3的制备及性能研究

Preparation and Characterization of Li_3V_2(PO_4)_3 Cathode Material for Lithium Ion Batteries

单斜结构的Li3V2(PO4)3是很有前途的聚阴离子型锂离子电池正极材料．将一定配比的LiOH·H2O、V2O5、H3PO4和蔗糖(C12H22O11)通过球磨均匀混合,在氮气保护下于800℃焙烧16h,通过碳热还原合成了Li3V2(PO4)3．用X射线衍射和扫描电镜分析对材料的结构和形貌进行了表征．充放电测试表明,在电压范围为3．0-4．3V和3．0-4．8V时,Li3V2(PO4)3正极材料具有较高的比容量、优良的循环性能和倍率特性．在电压范围为1．5-4．8V时,Li3V2(PO4)3正极材料具有很高的比容量,但循环性能较差．

Monoclinic lithium vanadium phosphate Li3V2（PO4）3 is a very promising polyaniontype cathode material for lithium ion batteries. In this work, LiOH·H2O, V2O5, H3PO4 and sucrose（C12H22O11） were homogeneously mixed with certain molar ratios by ball-milling, and then sintered at 800℃ for 16h in N2. The Li3V2（PO4）3 powders were finally synthesized via carbothermal reduction process. The structure and morphology of Li3V2（PO4）3 powders were characterized by XRD and SEM. At charge-discharge cut-off voltages of 3.0-4.3V and 3.0-4.8V, the material shows rather high specific capacity, excellent cycling performance and rate capability. At charge-discharge cut-off voltages of 1.5-4.8V, the material shows very high specific capacity but poor cycling performance.