Co^(3+)掺杂对LiNi_(0.5)Mn_(1.5)O_4导电性和倍率性能的影响研究

Effect of Co Doping on Performance of LiNi_(0.5)Mn_(1.5)O_4 Cathode Materials

采用聚合物辅助法制备了Co^(3+)掺杂的LiNi_(0.5)Mn_(1.5)O_4正极材料,并用X射线衍射(XRD)分析了材料的结构。XRD图谱表明,Co^(3+)掺杂的材料仍具有Fd3m尖晶石结构。随着Co^(3+)掺杂量的增多,Li_xNi_(1-x)O杂质相逐渐消失。采用恒流充放电试验和电化学阻抗谱(EIS)研究了电化学性能。电化学测试结果表明,随着Co^(3+)掺杂量的增加,电荷转移电阻显著降低,同时锂离子扩散系数明显增强、倍率放电性能得到有效改善。

The Co^3＋ doped LiNi0.5Mn1.5O4 cathode materials were synthesized by polymer assisted method,and the structure of the materials were characterized by X-ray diffraction（ XRD）. XRD patterns indicated that all samples showed spinel structure. Results showed that Co^3＋doped can reduce the impure phase LixNi1-xO. The electrochemical performance was studied by galvanostatic charge-discharge testing and electrochemical impedance spectroscopy（ EIS）. The results showed that the charge transfer resistance significantly decreased with increase of Co doping content,and the diffusion coefficient of Li ions were prominently enhanced,which led to significantly improved rate capability.