LiNi_xMn_(2-x)O_4对锂离子电池材料LiCoO_2的表面改性研究  

Research on LiNi_xMn_(2-x)O_4 surface modification of LiCoO_2 as cathode materials for Li-ion batteries

作　　者：姚晓林[1] 张承平[2] 陈春华[2] 

机构地区：[1]安徽农业大学理学院,安徽合肥230036 [2]中国科学技术大学化学与材料科学学院,安徽合肥230026

出　　处：《中国科学技术大学学报》2009年第4期375-379,共5页JUSTC

基　　金：国家自然科学基金(50372064)资助

摘　　要：在锂离子电池正极材料LiCoO2表面上修饰LiNixMn2-xO4来改善LiCoO2在循环过程中的容量衰减问题.对所得产物进行了XRD、SEM表征,并进行了充放电容量测试和交流阻抗测试.通过XRD和SEM,发现LiNixMn2-xO4修饰没有改变材料的晶体结构.在电化学性能测试中,由于包覆LiNixMn2-xO4可以减少材料与电解液的直接接触,最大程度地减缓电极材料在电化学循环时结构遭到破坏,在修饰量较小(3.5%)时,该改性方法改善了LiCoO2电极的循环性能,69次循环后放电比容量没有衰减,且大大地提高了平台效率.LiCoO2 was coated with a thin layer of LiNixMn2-x O4 on its surface to improve its structuralstability as cathode materials of lithium ion batteries during cycling. XRD, SEM and electrochemical tests were performed to investigate the surface morphology, structure and electrochemical properties of the LiNixMn2-xO4-coated LiCoO2. It is found that the surface modification has improved the cycle stability of the material significantly. The results show that LiCoO2 coated with a small amount （3. 5%） of LiNixMn2-xO4 exhibits good charge-discharge properties, and retains its initial reversible capacity after 69 cycles. The layer of LiNixMn2-xO4 prevents the LiCoO2 from getting in touch with electrolyte directly, thus reducing capacity loss, and greatly increasing its plateau efficiency.

关 键 词：锂离子电池 LICOO2 表面修饰 LiNiXMn2-xO4 平台效率 

分 类 号：O646.21[理学—物理化学] TM911[理学—化学]