沥青炭包覆微晶石墨用作锂离子电池负极材料的研究  

Study on coal-tar pitch carbon coated microcrystalline graphite used as lithium ion batteries anode

作　　者：肖海河[1] 刘洪波[1] 何月德[1] 简志敏[1] 匡加才[2] 

机构地区：[1]湖南大学材料科学与工程学院,湖南长沙410082 [2]长沙理工大学材料科学与工程研究所,湖南长沙410114

出　　处：《功能材料》2013年第19期2759-2763,共5页Journal of Functional Materials

基　　金：国土资源部公益性行业科研专项资助项目(201011031);湖南省国土厅科技资助项目(2010-08)

摘　　要：针对微晶石墨振实密度低和首次库仑效率低的缺点,采用真空浸渍-炭化工艺对微晶石墨进行沥青炭包覆改性,利用XRD、拉曼光谱和SEM等分析了炭包覆前后微晶石墨的结构和表面形貌,利用比表面测试仪测试了样品的BET比表面积,利用振实密度仪测定振实密度,并通过恒电流充放电和循环伏安等测试了样品的电化学性能。结果表明,炭包覆后微晶石墨的石墨化度略有降低,拉曼R值由0.63增大至0.85;颗粒表面更光滑平整,BET比表面积降低0.9m2/g,振实密度从0.95g/cm3提高至1.08g/cm3;不可逆容量损失从121mAh/g减小到44mAh/g,可逆容量从300mAh/g提高到320mAh/g,首次库仑效率从71.2%提高到87.4%,而且循环性能得到明显改善。To address the shortcomings, such as low tap density and low first cycle Coulombic efficiency of mi- crocrystalline graphite when used as lithium ion battery anode, the paper investigated the liquid phase coating for microcrystalline graphite using vacuum impregnation method. The microscopic structure of the coated sam- ple was tested with XRD, Raman spectrum. The surface feature was characterized by SEM and nitrogen ad- sorption-desorption. The performance of the sample was determined by galvanostatic test and CV test. It shows that after the modification, the degree of graphitization was reduced slightly, the Raman R value increases from 0.63 to 0.85, the surface of the graphite particles become neater and smoother, the BET specific surface area decreases by 0.9m2/g, and the tap density increases from 0.95 to 1.08g/ma. The electrochemical performance of the modified graphite was significantly improved, and the irreversible capacity was reduced from 121 to 44mAh/g. The reversible capacity increases from 300 to 320mAh/g, the initial Coulombic efficiency increases from 71.2% to 87.4%. The cycle stability was improved significantly.

关 键 词：锂离子电池 微晶石墨 炭包覆 真空浸渍 

分 类 号：TM911[电气工程—电力电子与电力传动]