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化学学报
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化学学报 ›› 2006, Vol. 64 ›› Issue (7): 605-610. 上一篇    下一篇

研究论文

尖晶石锂锰氧结构中的氧缺陷及其修复方法

唐爱东，黄可龙*，刘素琴   

  1. (中南大学化学化工学院功能材料化学研究所 长沙 410083)
  • 投稿日期:2005-04-25 修回日期:2005-12-19 发布日期:2006-04-15
  • 通讯作者: 黄可龙

Oxygen Defects of Spinel Li-Mn-O Compounds and Methods to Remove Such Oxygen Defects

TANG Ai-Dong, HUANG Ke-Long*, LIU Su-Qin   

  1. (Institute of Functional Materials Chemistry, School of Chemistry and Chemical Engineering,
    Central South University, Changsha 410083)
  • Received:2005-04-25 Revised:2005-12-19 Published:2006-04-15
  • Contact: HUANG Ke-Long

PDF

1149

被引次数

9

研究了氧缺陷型尖晶石锂锰氧化物的结构与电化学性能, 根据缺陷化学理论提出了弥补氧缺陷的办法. X射线衍射(XRD)结果表明, 在真空条件下于750 ℃焙烧不同时间后锂锰氧化物主要物相仍可保持尖晶石结构, 并伴随有少量Mn3O4和Li2MnO3杂相. 充放电测试及交流阻抗结果表明, 锂锰氧化物材料的放电容量随氧缺陷的增加而降低, 随着氧缺陷的增大, 表面膜阻抗及电荷传递阻抗增大、锂离子在锂锰氧固体中的嵌入与累积量减小使电化学性能恶化. 加入LiOH•H2O和通入氧气焙烧可在一定程度上修复氧缺陷.

关键词: 锂锰氧化物, 氧缺陷, 电化学性能

The structure and electrochemical properties of the spinel Li-Mn-O compounds with oxygen deficiency were investigated using X-ray diffraction (XRD), charge-discharge test and electrochemical impedance spectra (EIS). A method to remove oxygen deficiency was suggested in this paper. The XRD results indicate that the spinel Li-Mn-O compounds sintered at 750 ℃ under vacuum atmosphere for different hours mostly kept spinel structure with a few of Mn3O4 and Li2MnO3 impurities. The results of charge- discharge test and EIS showed that the specific capacities were decreased with increasing the amount of oxygen vacancy, and deterioration of the electrochemical properties could be contributed to the increase of the surface film resistance, charge-transfer resistance and the decrease of the intercalation capacities with the amount of oxygen vacancy. Sintering the samples with oxygen defects by addition of LiOH•H2O or O2 flowing can remove the oxygen deficiency inside the spinel Li-Mn-O compounds.

Key words: lithium manganese oxide, oxygen defect, electrochemical property