磷酸亚铁锂的合成及充放电性能研究

Synthesis of LiFePO_4 and Its Electrochemical Performance

使用固相合成法在不同温度下合成磷酸亚铁锂 .以它为正极活性物质组装成模拟电池测试充放电性能 .使用 XRD和 IR表征样品 .测试结果表明磷酸亚铁锂电池具有平稳的放电平台 ,良好的循环性能 .在0 .0 5 m A/cm2的电流密度下 ,60 0℃合成的样品初始放电容量达到 90 m Ah/g,第 1 0个循环的放电容量达到1 0 0 m Ah/g,80个循环后放电容量仍保持初始容量的 97%以上 ,表明它具有优秀的循环性能 . 5 0 0℃合成的样品中有杂相存在 ,70 0℃合成的样品的晶粒度过大 ,这两个因素都可能使放电容量降低 .在本实验条件下 ,60 0℃是较佳合成温度.

Lithium iron(Ⅱ) phosphate was synthesized at different temperatures by solid state synthesis method and the performance of the cathodes was evaluated using analogous cells. The samples were characterized by X-ray diffraction and Infrared Ray absorption spectrum. The sample synthesized at 600℃ had discharge capacity of 90 mAh/g at the first cycle, and 100 mAh/g at the 10 th cycle .Its capacity kept more than 97% of the first cycle after 80 cycles. It was shown that lithium iron(Ⅱ) phosphate had long cycle life and was a potential cathode material to replace lithium cobalt oxide.