LaF_3表面修饰LiMn_2O_4的合成方法及电化学性能的研究(英文)

La F_3-Coated Li Mn_2O_4: Synthesis and Improved Performance

通过高温固相法制得尖晶石LiMn2O4,然后在通过简单易行的无水乙醇蒸干法包覆LaF3来修饰LiMn2O4。利用XRD,SEM来表征LaF3修饰的LiMn2O4的结构和形貌特征,并通过电化学测试研究LaF3修饰LiMn2O4的高温和常温下的电化学性能,另外结合电化学阻抗谱(EIS)和循环伏安(CV)考察表面修饰的锰酸锂的循环阻抗和循环可逆性。结果显示:经LaF3修饰过的LiMn2O4仍具有尖晶石结构,并且具有良好的电学性能。其中,以3wt%的修饰效果最好,常温循环100次和高温循环50次的循环保持率分别是91%和90%;而且,EIS和CV分别表明经LaF3修饰的LiMn2O4的电荷传递阻抗明显减小,其循环可逆性也明显提高。

Spinel Li Mn2O4 was coated by La F3 via a facile immersion-evaporation process. The results of the Xray diffraction（XRD） and scanning electron microscope（SEM） indicate that the surface of all La F3-coated Li Mn2O4 samples is homogeneously covered by La F3, while the spinel structure remains. The electrochemical performances of all samples were investigated at 25 ℃ and 55 ℃, respectively. The results show that the electrochemical performance of all La F3-coated Li Mn2O4 is better than that of pristine-Li Mn2O4. Among them, the3wt% La F3-coated Li Mn2O4 has the best cycling and rate performance compared to other samples, with the capacity retention of 91% at room temperature and 90 % at 55 ℃.