微氧化处理对球形石墨结构及电化学行为的影响  

Influences of Mild Oxidation Treatment on the Structure and Electrochemical Behavior of Spherical Graphite

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

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

出　　处：《无机材料学报》2012年第2期151-156,共6页Journal of Inorganic Materials

基　　金：国土资源部公益性行业科研专项经费(201011031);湖南省国土资源厅科技项目(2010-08)~~

摘　　要：研究了微氧化处理对球形石墨的晶体结构、表面形貌和电化学行为的影响.采用XRD、Raman光谱和SEM等手段分析了样品的结构和形貌,并采用恒电流充放电测试、粉末微电极技术和慢速扫描循环伏安法(SSCV)研究了微氧化前后石墨负极的电化学行为.结果表明,微氧化后石墨颗粒中的结构缺陷增多,近表面区域的无序度增大,面内平均晶粒尺寸La减小,且菱形相含量降低,石墨呈不规则的鳞片状,部分层面的边缘有卷曲与刻蚀现象.微氧化后石墨负极的第三次脱锂容量从345.5 mAh/g增加至381.4 mAh/g,且其循环性能得到有效改善.同时,微氧化后锂离子较容易从石墨中脱出,脱锂过程中一阶Li-GICs(lithium-graphite intercalation compounds,简称Li-GICs)向二阶Li-GICs的阶转变可在较低的电位下发生.The effects of mild oxidation treatment on the crystal structure,morphology and electrochemical behavior of spherical graphite were investigated.The structure and morphology of the samples were characterized by XRD,Raman spectra and SEM analysis,respectively.The electrochemical behavior of the samples was studied using galvanostatic charge/discharge test,powder cavity microelectrode technique and slow scan rate cyclic voltammograms.The results indicate that structural defects in graphite particles and disordered degree of near surface region of graphite increase after modification,while the average in-plane crystallite domain size La and content of rhombohedral phase decrease.The graphite particles present irregular flake shape and some graphene sheets show flexual and sculptural margin.Electrochemical measures show that reversible capacity of modified graphite increases from 345.5 mAh/g to 381.4 mAh/g,and cycling performance is improved.During deintercalation process of the modified graphite,stage transformation from stage 1 Li-GICs（lithium-graphite intercalation compounds） to stage 2 Li-GICs begins to happen at lower voltage,compared with that of the raw graphite.

关 键 词：锂离子电池 负极材料 球形石墨 氧化处理 电化学行为 

分 类 号：TM912[电气工程—电力电子与电力传动]