三元掺杂尖晶石LiMn2O4正极材料的制备与电化学性能研究

Preparation and electrochemical performance of ternary doped spinel LiMn2O4 anode material

采用溶胶-凝胶法制备了三元掺杂改性的尖晶石型锰酸锂正极材料[LiAlxCo0.05Mg0.05Mn1.9-xO4(x=0、0.02、0.05)]。通过X射线衍射(XRD)和扫描电镜(SEM)对材料进行了表征。结果表明:掺杂后的材料仍为尖晶石结构,无杂质相。SEM结果显示合成材料具有良好的粒径分布及形貌。通过充放电测试发现,掺杂过后的材料在高温下的电化学性能有很大程度的改善。其中,LiAl0.02Co0.05Mg0.05Mn1.88O4具有最好的电化学性能,在55℃、0.2C倍率下首次放电比容量达到128.2mAh/g,循环40次后容量保持率仍能达到95.2%。

The modified spinel[LiAlxCo0.05Mg0.05Mn1.9-x(x=0,0.02,0.05)]with three kinds of ions doped was synthesized by the sol-gel method.These prepared anode material were characterized by X-ray diffraction(XRD)and scanning electron microscope(SEM).XRD results demonstrated that the as-prepared manganic acid lithium anode materials possessed the spinel structure without any impurity phase.SEM showed that the materials had superior particle size distribution and mophology.Finally,charge-discharge testing indicated that the electrochemical properties of the materials were greatly improved under high temperature after doping modification.LiAl0.02Co0.05Mg0.05Mn1.88O4 possessed the best electrochemical performance among all of the samples,where the initial specific capacity reached128.2 mAh/g under 55℃ at 0.2 C,and the capacity retention rate can still reach to 95.2% after 40 cycles.