层状的LiNi_(0.5)Mn_(0.5)O_2合成及其电化学性能

Synthesis and electrochemical performance of layered LiNi_(0.5)Mn_(0.5)O_2

采用超声波辅助溶胶-凝胶法合成层状的锂离子电池的正极材料LiNi0.5Mn0.5O2,并用热重分析、X射线衍射(XRD)、扫描电子显微镜(SEM)对材料的结构与形貌进行了研究,电化学性能采用循环伏安法(CV)、交流阻抗和充放电测试进行表征。结果表明,在950℃灼烧12h的材料结晶度比较好,其晶胞参数a=0.2879nm,c=1.431nm,结构比较理想。当材料在2.8～4.2V间进行充放电时,其首次放电容量为170mAh/g,50次循环后容量的保持率为89%。

The cathode material LiNi0.5Mn0.5O2 is prepared by the ultrasonic assisted sol-gel method. Structure, appearance and electrochemical performance of the material were characterized by TG, XRD, SEM and electrochemical tests. The results indicate that the material of heat treatment of 950 ℃ in 12 h presents good crystallinity with lattice parameters of a=-0.287 9 nm, c=1.431 nm. Initial discharge capacity of 170 mAh/g was obtained in the range 2.8-4.2 V. 89% of the initial discharge capacity was reserved after 50 cycles.