以氧化铁为铁源制备磷酸铁锂的反应机制研究  

Reaction Mechanism of Synthesizing LiFePO_4/C Using Fe_2O_3 as Raw Material

作　　者：冯泽荣[1] 张俊英[1] 张中太[2] 唐子龙[2] 黄彦[1] 吉双泽[1] 

机构地区：[1]北京航空航天大学理学院材料物理与化学研究中心,北京100191 [2]清华大学材料科学与工程系,新型陶瓷与精细工艺国家重点实验室,北京100084

出　　处：《稀有金属》2009年第3期361-365,共5页Chinese Journal of Rare Metals

基　　金：国家863计划项目(2007AA03Z235)资助

摘　　要：以氧化铁和磷酸二氢锂为原料,采用碳热还原法制备磷酸铁锂正极材料。用热重-差热分析(TG-DSC)、X射线衍射(XRD)、扫描电镜(SEM)等方法来表征反应中间产物性质,分析研究碳热还原制备磷酸铁锂的反应机制,并通过分光光度法测定反应过程中亚铁离子含量。研究结果表明:该反应过程主要可分为三个阶段,第一为室温～200℃低温阶段,在此阶段Fe2O3被还原成Fe3O4;第二为200～600℃中温阶段,在400℃左右FeO进一步被还原为FeO;第三为600～800℃高温阶段,在600℃之后FeO与磷酸二氢锂发生置换反应生成磷酸铁锂。The cathode material LiFePO4 was prepared by carbothermal method with LiH2PO4 and Fe2O3 as raw materials. The reaction mechanism of carbotherreal method was investigated by thermogravimetric analysis, X-ray diffraction, and scanning electric microscopy. Further more, the ferrite content of the powder obtained at different calcination temperatures was verified by spectrophotometer. The research results showed that the reaction could be divided into three stages. The first was low temperature stage, from room temperature to 200 ℃, when the ferroferric oxide was generated at 200 ℃ via the reduction of Fe2O3 to Fe3O4. The second was medium temperature stage （200 -600 ℃ ） , and Fe3O4 was deoxidized into FeO. The third was high temperature stage （600 - 800 ℃ ）, in which the replacement reaction of LiH2 PO4 by FeO happened, and the lithium iron phosphate was synthesized.

关 键 词：碳热还原法 磷酸铁锂 铁碳还原 亚铁含量 

分 类 号：TM910.4[电气工程—电力电子与电力传动]