核壳结构的5V正极材料微球合成与改善的电化学性能  

Synthesis and electrochemical performance of core-shell structured LiNi_(0.5)Mn_(1.5)O_4 microspheres for lithium ion batteries

作　　者：邓苗苗 唐仲丰 邵宇 邹邦坤 陈春华[1] Miao-Miao Deng;Zhong-Feng Tang;Yu Shao;Bang-Kun Zou;Chun-Hua Chen(Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China;School of Chemistry and Chemical Engineering, Heifei University of Technology, Hefei 230009, China)

机构地区：[1]中国科学技术大学化学与材料科学学院,合肥230026 [2]合肥工业大学化学与化工学院,合肥230009

出　　处：《中国科学：化学》2018年第9期1141-1148,共8页SCIENTIA SINICA Chimica

基　　金：国家重点研发计划(编号:2018YFB0905400);国家自然科学基金(编号:U1630106;51577175)资助项目

摘　　要：本文采用多步骤合成路线,分别制备了具有实心、空心和核壳结构的5 V LiNi_(0.5)Mn_(1.5)O_4正极材料微球.同时利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)和红外光谱(FTIR)等分析手段研究了上述材料的结构特征.其中SEM和TEM证实了所制备的镍锰尖晶石微球具有实心、空心和核壳结构.电化学性能测试进一步表明,核壳结构的LiNi_(0.5)Mn_(1.5)O_4正极材料在55℃条件下表现出良好的循环稳定性和优异的倍率性能,在8 C倍率下依然有98 mAhg^(-1)的放电比容量.其改善的电化学性能源于独特的核壳微观结构,不仅可以提高结构的稳定性,而且可以缩短锂离子的扩散路径.The 5 V-cathode material LiNi0.5Mn1.5O4 microspheres with hollow, solid or core-shelled inner structures for the lithium-ion batteries are designed and fabricated by a multi-step synthesis procedure. Scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, powder X-ray diffraction （XRD） analysis, Fourier transformed infrared （FTIR） are employed to characterize the microstructures. Compared with the hollow and solid inner structures, the core-shell structured LiNi0.5Mn1.5O4 exhibits excellent cycling stability and outstanding rate performance, which delivers a discharge capacity of 111.5 mA h g-1 after 200 cycles at 1 C, and 98 mA h g 1 at 8 C, respectively. Further analyses with cyclic voltammetry and electrochemical impedance spectroscopy demonstrate that the core-shell structure can provide structural stability and shortened lithium diffusion path at both room and elevated temperatures.

关 键 词：锂离子电池 锂镍锰金属氧化物 微观结构 正极 电化学性能 

分 类 号：TM912[电气工程—电力电子与电力传动]