Li/Mn比对改性LiMn_2O_4材料的电化学性能影响

Effect of ratios of Li/Mn on electrochemical performance of modified LiMn_2O_4

采用溶胶-凝胶法对LiMn2O4进行Al,Mg,F的复合掺杂,并考察了Li/Mn比对正极材料电化学性能的影响。材料的晶体结构通过X射线衍射光谱法(XRD)进行表征,而其电化学性能通过循环伏安法(CV)和恒流充放电进行表征。制备样品的CV图具有尖晶石典型的两对氧化-还原峰;电化学性能测试结果表明,LiAl0.03Mg0.03Mn1.91O4F0.05具有最佳的电化学性能,这是由于在多元素复合掺杂的基础上,由于F的引入,使得Li/Mn比最小时,可以有效地抑制Jahn-Teller效应。

Multiple doped Li-Mn spinel as Li-ion battery cathode materials were successfully synthesized by citric acid sol-gel method, and effects of the ratios of Li/Mn on electrochemical performance of the modified LiMn2O4 were investigated. The crystal structure of the materials was characterized by X-ray powder diffraction. Electrochemical properties were characterized by cyclic voltammetry and galvanostatic charge and discharge methods. The CV curves of the as-prepared materials shows two typical redox couples of spinel LiMn2O4. The galvanostatic charge and discharge test results show that the LiAl0.03 Mg0.03 Mn1.91 O4F0.05 has the best electrochemical performance. Based on the multiple doping, due to the introduction of F element, the ratio of Li/Mn can be reduced to restrain Jahn-Teller effect.