改良水热法合成磷酸亚铁锂的研究

采用水热法制备的磷酸亚铁锂(LiFePO4)正极材料具有颗粒细小、粒径分布窄等特点;且水热法本身具有工艺条件易于控制、能耗低等优点,有望解决当前LiFePO4生产批次不稳定的难题,是一种有应用前景的LiFePO4生产方法。传统水热制备工艺需要加入过量锂,增加了生产成本。改良水热法制备LiFePO4,选择非纯水溶剂,极大地减少了锂用量,有利于Li+沉淀,且抑制了晶体的过度发育和颗粒间的团聚,加快LiFePO4成核、降低晶体生长速率,减小粒径。材料的大倍率放电性能比传统水热法优越,10 C放电比容量达94 mAh/g。随后研究水热合成温度、时间对样品性能的影响,结果表明:反应温度170℃,反应时间12 h合成的样品晶型结构完善,循环电性能最佳。

Study on novel hydrothermal synthesis of LiFePO4

The cathode material LiFePO4 synthesized by hydrothermal method has the superior characteristics such as small particles,uniform distribution;Hydrothermal synthesis process has great prospects for commercial applications because of its instinct advantages like controlled condition and low energy consumption,which is expected to solve the current LiFePO4 problems of production batch instability.The traditional technology requires excessive amount of lithium salt,which increases the production costs.The novel way using component solvent could reduce the amount of lithium,which was beneficial to Li+ precipitation,inhibit the growth of crystals and grain of reunion,accelerate LiFePO4 nucleation,depress crystal growth rate,and reduce particle size.Comparing with the traditional method,LiFePO4 synthesized by the improved one had a few superiority in high current filed,and the discharge specific capacity is 94 mAh/g at 10 C rate.Then the effect of hydrothermal synthesis temperature and time on properties of the sample was studied.The result shows that,the sample synthesized at 170 ℃ for 12 h has perfect crystal structure and the best recycling electrical properties.