合成原料对LiMn2O4电化学性能的影响研究

Effect of Raw Materials on the Electrochemical Properties of LiMn2O4

摘要:

以电解MnO2、Mn3O4、Li2CO3为原料，采用固相法合成尖晶石LiMn2O4。采用X-射线衍射、扫描电子显微镜、循环伏安及恒电流充放电等技术检测和分析合成产物的物相、形貌及电化学性能。结果表明：与采用电解MnO2制备的LiMn2O4相比，采用Mn3O4制备的LiMn2O4粉末X-射线衍射峰强度更大，首次放电比容量为128.7mAh/g，高于采用电解MnO2制备的LiMn2O4比容量123.7mAh/g，室温30次循环后容量保持率为98.4%，高于采用电解MnO2制备的LiMn2O4容量保持率85.0%。采用Mn3O4制备的LiMn2O4粉末55℃循环30次后的容量保持率为91.0%，高于采用电解MnO2制备的LiMn2O4容量保持率80.3%。

Abstract:

Spinel LiMn2O4 was synthesized via solid state process with different raw materials. The phase identification, surface morphology and electrochemical properties of the synthesized powders were characterized with x-ray diffraction, scanning electron micrograph, cyclic voltammetry and galvanostatic charge-discharge experiments. LiMn2O4 powders prepared by Mn3O4 shows better crystallization than the one prepared by electrolytic MnO2(EMD). The specific capacity of LiMn2O4 prepared by Mn3O4 is 128.7mAh/g, which is slightly higher than that of 123.7mAh/g for LiMn2O4 prepared by electrolytic MnO2. The capacity retention of the LiMn2O4 prepared by Mn3O4 after being cycled 30 times at room temperature and room temperature of 55℃ is 98.4% and 85.0% respectively, which are much higher than the values of 91.03% and 80.3% for the one prepared by electrolytic MnO2. Preparation of LiMn2O4 by Mn3O4 can not only improve the specific capacity but also significantly increase the cycle performance and high temperature performance.