气相沉积碳包覆磷酸铁锂的制备及性能  

PREPARATION AND CHARACTERIZATION OF CARBON COATED LiFePO_4 BY THE CHEMICAL VAPOR DEPOSITION

作　　者：蒋永[1] 赵兵[1] 万小娟[1] 焦正[1] 吴明红[1] 仲明阳[1] 栾健 陈仁国 

机构地区：[1]上海大学环境与化学工程学院,上海200444 [2]泰州赛科电池有限公司,江苏泰州225423

出　　处：《硅酸盐学报》2008年第9期1295-1299,共5页Journal of The Chinese Ceramic Society

基　　金：上海市教委重点(06ZZ01;07ZZ01);上海市重点学科(T0105);上海市优秀青年教师科研基金(B99-0303-06-016);江苏省自然科学基金(BK2006086)资助项目

摘　　要：磷酸铁锂是一种新型的锂离子电池正极材料,具有原材料来源丰富、价格低廉、对环境友好等特点。包覆碳及加碳制成复合材料是提高LiFePO4材料电导率的有效方法之一。实验中以苯为碳源,采用化学气相沉积方法在固相反应法制备LiFePO4材料的过程中对材料表面进行碳包覆。用X射线衍射分析,扫描电镜和透射电镜对碳包覆LiFePO4材料的结构形貌进行了表征。用电池测试系统对其电化学性能进行了研究。结果表明:以苯为碳源的化学气相沉积方法合成的LiFePO4材料的平均粒径为200nm,材料表面均匀地包覆了4～5nm厚的碳层。电化学性能测试表明:碳包覆LiFePO4在0.1C倍率下放电容量达到151.6mAh/g,1C放电容量达到125.8mAh/g,体现了良好的倍率放电特性和循环性能。The olivine LiFePO4 has been becoming one of the alternative cathode materials for lithium ion battery for its abundant source supply, low cost and environmental benignancy. Carbon coating is very effective to enhance the electric conductivity of the LiFePO4/C composite. In this work, the chemical vapor deposition （CVD） method was applied to form carbon coating on the surface of LiFePO4 during the solid-state reaction process using benzene as carbon source. The structure and electrochemistry performance of carbon coated LiFePO4 were studied through the methods of X-ray diffraction, scanning electron microscope, transmission electron microscope and charge and discharge at constant current density. The results indicate that the average size of the crystallites of LiFePO4 material is about 200 nm and the thickness of the coating carbon varies from 4 nm to 5 nm. Testing of the electrochemical performance shows that the specific discharge capacities of carbon coated LiFePO4 are 151.6 mAh/g and 125.8 mAh/g at the 0.1 C and 1 C rate respectively. These results reveal the good cycling stability and rate capacity of the LiFePO4 material.

关 键 词：锂离子电池 化学气相沉积 正极材料 碳包覆 磷酸铁锂 

分 类 号：O646[理学—物理化学]