机械活化对碳热还原法LiFePO_4结构与性能的影响  

Effects of mechanical activation on structure and properties of LiFePO_4 prepared by carbothermal reduction method

作　　者：杜伟[1] 周震涛[1] 刘金成 

机构地区：[1]华南理工大学材料科学与工程学院,广东广州510640 [2]惠州亿纬锂能股份有限公司,广东惠州516006

出　　处：《电源技术》2011年第4期385-389,共5页Chinese Journal of Power Sources

摘　　要：为了考察机械活化对碳热还原法磷酸铁锂结构与性能的影响,采用机械活化与碳热还原相结合的方法制备了LiFePO4/C正极材料,考察了前驱体的机械活化工艺(球料比、球磨介质、球磨气氛、球磨温度)等因素对LiFePO4/C材料结构与电性能的影响。利用X射线衍射仪(XRD)、扫描电镜(SEM)、粒径分析仪、比表面仪和恒流充放电技术等对材料的微观结构和电性能进行了表征。研究结果表明,磷酸铁锂材料制备过程中最优的前驱体机械活化工艺为:球料比为6∶1,在25℃的氩气气氛下于玛瑙球磨罐中球磨。据此所制备的LiFePO4/C材料的晶粒尺寸约为500～600 nm,具有良好的电化学性能,1 C倍率首次放电比容量可达138 mAh/g。LiFePO4/C cathode material was synthesized by mechanical activation combined with carbothermal reduction method.The influences of parameters of mechanical activation（ball-to-power weight ratio,milling media,the atmosphere,temperature of ball-milling） on the structure and performance of the material were investigated.The structure,morphology and electrochemical properties of LiFePO4/C were analyzed by XRD,SEM,optical particle size analyzer,BET method and galvanostatic charge-discharge method,respectively.The results indicate that the optimum processing conditions of mechanical activation are ball-to-power weight ratio =6∶1,ball-milling at 25 ℃ for 6 h with Ar protect atmosphere in agate jar.LiFePO4/C composite material synthesized under this processing condition has fine particle size at 500-600 nm and excellent electrochemical performance with 136 mAh/g at 1 C discharge current.

关 键 词：机械活化 碳热还原法 LIFEPO4 正极材料 比容量 

分 类 号：TM912.9[电气工程—电力电子与电力传动]