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通过低温溶剂热的方法成功制备出了LiCr0.2Ni0.4Mn1.4O4尖晶石正极材料。通过此法,溶液的饱和蒸汽压急剧降低且在室温(25℃)下即可沸腾。所有的金属离子可在随后的热聚合过程中均匀分散且煅烧后所得材料无杂质相生成。采用了热重分析,X射线衍射,扫描电镜、循环伏安,交流阻抗等测试手段对材料进行了表征。结果表明:此法所得材料含有Mn3+,为Fd3m晶型,且其形貌规则、粒度分布均一。1C和10C下放电容量为140.5和121.0 mAh·g-1,10C下100次循环容量保持率高达96.9%。其优异的电化学性能可归因于均相的前驱体制备过程,高结晶度且无杂相生成,以及较高的锂离子扩散系数诸因素的共同作用。
LiCr0.2Ni0.4Mn1.4O4 spinel cathode material was successfully prepared by low-temperature solvothermal method. With this method, the saturated vapor pressure of the solution decreases sharply and boils at room temperature (25 ° C). All the metal ions can be uniformly dispersed during the subsequent thermal polymerization and the resulting material is free of impurity phase after calcination. The materials were characterized by thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, cyclic voltammetry and AC impedance. The results show that the material obtained by this method contains Mn3 + as the crystal form of Fd3m, and its morphology and size distribution are uniform. The discharge capacities at 1C and 10C were 140.5 and 121.0 mAh · g-1, respectively, and the capacity retention at 10 cycles was up to 96.9%. Its excellent electrochemical performance can be attributed to the homogeneous precursor preparation process, high crystallinity and no impurity generation, as well as the high lithium ion diffusion coefficient of the combined effect of various factors.