LiFePO_4的制备、结构与电性能研究

The Synthesis,Structure and Electrochemical Performances of Lithium Iron Phosphate

应用高速球磨．高温固相反应法于不同煅烧温度（400—700℃）下合成LiFePO4锂离子电池正极材料，X-射线衍射、扫描电镜和恒电流充放电等测试表明，煅烧温度对合成的LiFePO4晶体结构、表观形貌以及电化学性能均有很大影响；经600℃煅烧得到的LiFePO4样品具有良好的充放电性能，以0．1C倍率充放电，首次放电比容量为128．8mAh/g，第15次放电比容量为129．1mAh／g，充放电效率在99．7％以上；其高温充放电性能亦佳．

The lithium iron phosphate cathode materials were synthesized by solid-state reaction combined high-rate ball milling under the temperature ranging from 400 ℃ to 700 ℃. The crystalline structure, morphology of particles, and electrochemical performance of the sample were investigated by X-ray diffraction, scanning electron microscopy and charge-discharge test. The results showed that the sintering temperature had great influences on the crystal structure, morphology and electrochemical performances of LiFePO4. The sample synthesized under 600℃ showed the best charge-discharge performances with the first specific discharge capacity of 128.8 mAh/g and the 15^th specific discharge capacity of 129.1 mAh/g at 0.1C rate, each charge-discharge cycling efficiency being 99.7%. Also the sample showed good electrochemical performances under higher temperatures.