锂离子电池正极材料Li[Li(0.167)Mn(0.583)Ni(0.25)]O2的合成与性能研究  

Synthesis and Electrochemical Characteristics of Li[Li_(0.167)Mn_(0.583)Ni_(0.25)]O_2 Cathode Material

作　　者：于凌燕[1] 仇卫华[1] 连芳[1] 黄佳原[1] 康晓丽[1] 刘伟[1] 

机构地区：[1]北京科技大学材料科学与工程学院北京市新能源材料与技术重点实验室

出　　处：《电化学》2008年第2期135-139,共5页Journal of Electrochemistry

基　　金：国家自然科学基金(50472093)资助

摘　　要：应用低热固相法制备镍锰复合正极材料Li[Li0.167Mn0.583Ni0.25]O2.XRD、FESEM和恒电流充放电测试表明,该材料结晶良好,可标定为α-NaFeO2型结构（空间群R3m）,颗粒粒径约为60-100 nm,粒度均匀细小.在2.5-4.4 V之间以0.5 C（100 mA/g）做充放电循环时,可逆比容量在120 mAh/g以上,循环性能非常稳定.如将截止电压升高到4.6 V,则比容量大大提高,最高可达234 mAh/g.上述充放电测试都出现了比容量随循环次数上升的现象.主要原因可归结为材料中Mn（Ⅳ）向Mn（Ⅲ）的转变,但在不同的电压范围内导致该转变的起因并不相同.The cathode material of Li[ Li0.167Mn0.583Ni0.25 ] O2 was synthesized by low-heat solid state reaction. The results of XRD and FESEM indicated that the powders of the material were well crystallized with the uniform diameters ranging from 60 nm to 100 nm and could be indexed as α-NaFeO2 structure（ R3m space）. Galvanostatic charge-discharge tests showed that the electrode delivered the capacity of about 120 mAh/g with good cyclability when cycled in 2, 5 - 4.4V at 0.5C. When the cut-off potential was set up to 4.6V, the cathode delivered much larger capacities with the maximum of 234 mAh/g. It was observed that the discharge capacity gradually increased with the increment of the cycle number. The transformation between Mn （ Ⅳ ） and Mn （ Ⅲ） could be responsible for the increasing capacity. However, the causes for this transformation in different potenticals varied.

关 键 词：锂离子电池 正极材料 固溶体 层状结构 低热固相法 

分 类 号：TM912[电气工程—电力电子与电力传动]