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摘要
A series of LiMn2O4 spinel was prepared by adipic acid-assisted sol-gel method at different temperatures. The structure and physicochemical properties of spinel LiMn2O4 synthesized by different temperatures were investigated by differential thermal analysis (DTA) and thermogravimetery (TG), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS). scanning electron micrographs (SEM), inductively coupled plasma-mass spectroscopy (ICP-MS), galvanostatic charge-discharge test, and cyclic voltammetry (CV), respectively. TG-DTA shows that the weight loss occurs in four temperature regions during the synthesis of LiMn2O4. XRD indicates that the sintering temperature affects the formation of spinel phase, and prominent LiMn2O4 spinel powder with smaller atom location confusion forms about 800 degrees C. XPS reveals that the manganese oxidation state in spinel lithium manganese oxide synthesized at different temperatures is between +3 and +4. SEM shows that LiMn2O4 spinel synthesized at 800 degrees C has the uniform, nearly cubic structure morphology with narrow size distribution. ICP-MS indicates that the average chemical valence of Mn element of LiMn2O4 synthesized at 800 degrees C is the most close to 3.5 among the samples synthesized at different temperatures. CV illustrates that the LiMn2O4 synthesized at 800 degrees C has the best electrochemical activity. Charge-discharge test explains that the capacity retention sintered at 350, 700 and 800 degrees C over the first 50 cycles is 93.6%, 86.1% and 85.2%, respectively, but the discharge capacity at the 50th cycle is 82.2,104.8 and 110.8 mAh g(-1), respectively.
- 出版日期2009-7
- 单位牡丹江师范学院; 安徽工业大学
