锂电池正极材料Li_3V_2(PO_4)_3的合成及电化学性能

Synthesis and performance of Li_3V_2(PO_4)_3 as cathode material for lithium-ion battery

采用碳热还原法（一步煅烧）合成了锂电池正极材料Li3v2（P04）3考察了合成温度对产物晶形结构及电化学性能的影响。结果表明，当煅烧温度为850℃时。所得样品为纯相Li3V2（P04）30利用扫描电镜（SEM）、比表面积测定仪、激光粒度仪和电化学测试手段，对850oC下煅烧16h得到的正极材料Li3v2（P04）3进行了表征和研究。从样品的SEM图可以看出材料有明显的团聚现象；样品比表面积及粒度分布的测试结果表明，材料虽然具有较大的比表面积（255m2／g）。但其中值粒径鸸0的值较大（6．6μm）。材料在3．0—4．3V时。以0．2C充放电时，首次放电比容量为127．3mAh／g。是理论容量的95．8％。经过30个循环后。放电比容量仍高达115．1mAh／g。以6C充放电时。首次放电比容量为105．0mAh／g，50个循环后．放电比容量仍高达83．1mAh／g。该材料有望部分取代昂贵的LiCoO：，也有望应用于动力型锂离子电池。

The Li3V2（PO4）3 could be synthesized by carbothermal reduction reaction method. The effects of reaction temperature on the crystal structure and electrochemical properties of products were investigated. The results show that the sample synthesized at 850 ~Cis pure. The properties of the sample were investigated using scanning electron microscopy （SEM）, electrochemical methods, et al. From the SEM image, it is shown that lots of particles are agglomerated. The results show that it has specific surface of 255 m2/g and the particle size d~ is 6.6 pm. It presents initial discharge specific capacity of 127.3 mAh/g （at 0.2 C）, and exhibits better cycling stability （115.1 mAh/g at 30 th cycle at 0.2 C） and better rate capability （83.1 mAh/g at 50th cycle under 6 C） in the voltage range of 3.0-4.3 V. It is expected to partly replace expensive LiCoO2 and also promising to be used in power lithium-ion batteries.