一种合成LiFePO_4的新方法  

A novel synthesis method for lithium iron phosphate cathode material

作　　者：张俊喜[1] 曹小卫[1] 徐娜[1] 张铃松[1] 颜立成[2] 张万友[3] 

机构地区：[1]上海电力学院电化学研究室国家电力公司热力设备腐蚀与防护重点实验室,上海200090 [2]杭州师范大学教务处,杭州310036 [3]东北电力大学应用化学系,吉林132000

出　　处：《材料研究学报》2008年第4期439-443,共5页Chinese Journal of Materials Research

基　　金：教育部科技研究重点205055;中国航天科工集团支撑技术基金DL01-2004;上海市重点学科建设基金P1304;上海市科委研发基地专项基金06DZ22010资助项目.~~

摘　　要：结合共沉淀原理和腐蚀电化学原理,提出了一种合成LiFePO_4的新方法.对新方法合成路线中的反应物、添加物以及热处理条件作了实验分析,并用XRD分析了LiFePO_4的晶体结构和晶粒尺寸分布,用SEM分析了形貌,用充放电测试技术分析了材料的比容量及其电化学性能.结果表明:新方法在合成中不引入其它杂质离子,避免了常规共沉淀合成工艺中过滤、洗涤等过程对LiFePO_4前驱体的不利影响.用新方法制备的LiFePO_4晶粒分布在20-70 nm,在0.1C下首次放电容量为147 mAh/g.新方法有利于对LiFePO_4的Mg^(2+)掺杂改性,明显地提高LiFe_(1-x)Mg_xPO_4的电化学性能.Combining the principle of coprecipitation and corrosion, nanocrystalline LiFePOa was obtained by spontaneous precipitation from equimolar iron powder and equimolar aqueous solutions of H3PO4 and LiOH, using CuO as an additive. The novel aspect of the synthesis is based on a critical step involving the addition of CuO powder to promote the dissolve of Fe powder in phosphate acid solution. The materials were characterized by thermogravimetric and differential thermal analysis, X-ray powder diffraction, scanning electron microscopy and electrochemical measurements. Results shows that the satisfying LiFePOa cathode materials with fine crystal grain in 20-70 nm can be obtained by using this synthesis route without introducing impurity ion; the first discharge capacity of the prepared LiFePO4 is 147 mAh/g. The results also suggest that this synthesis route is propitious to get doped LiFePO4 by adding Mg2＋ ion to promoting the electrochemical performance of LiFe1-xMgxPO4 cathode material.

关 键 词：无机非金属材料 磷酸铁锂 共沉淀 湿法合成 电化学性能 

分 类 号：TM912.9[电气工程—电力电子与电力传动]