尖晶石锂锰氧化物中氧缺陷对材料电化学性能的影响  

The Effect of the Population of Oxygen Vacancies on the Electrochemical Properties of Spinel Li_(1.07)Mn_(1.93O)_(4-δ)

作　　者：戴忠旭[1] 詹晖[2] 周运鸿[2] 桂嘉年[1] 王仁卉[1] 

机构地区：[1]武汉大学物理科学与技术学院,湖北武汉430072 [2]武汉大学化学与分子科学学院,湖北武汉430072

出　　处：《武汉大学学报（理学版）》2003年第3期345-349,共5页Journal of Wuhan University:Natural Science Edition

基　　金：国家自然科学基金资助项目 ( 10 1740 5 3 )

摘　　要：研究了富锂锂锰氧化物中氧缺陷对材料电化学性能的影响 .X射线衍射谱表明有氧缺陷的锂锰氧化物仍可保持尖晶石结构 ,当氧缺陷浓度达到一定程度时 ,高角度区的衍射峰出现分裂 ,说明其微观结构发生了变化 .充放电实验结果表明氧缺陷使 4V区的锂离子嵌脱变成了多步 ,模拟电池的容量微分曲线有 3对清晰的氧化还原峰 ,低电位的氧化还原峰被一分为二 .氧缺陷降低了材料的放电容量 ,同时引起低电位区的放电容量向更低电位区转移 ,使电化学性能恶化 .锂锰氧化物中氧缺陷对电化学性能的影响对此类材料的合成提供了理论和实践依据 .Three lithium-rich manganese oxides with oxygen deficiency, Li 1.07Mn 1.93O 4-δ, were obtained. Their structure and electrochemical characterizations were carried out. They have the spinel structure based on XRD analysis. It was observed that their specific capacities of charge/discharge reaction at 4V plateau decreased with increasing the population of oxygen vacancy. Their relationships of dQ/dV vs V all show three-step for lithium ion extraction and insertion instead of the two-step reaction. That is due to the peak splitting into two in low potential district. The effect of oxygen vacancies in lithium-rich manganese oxides on the electrochemical performance was discussed.

关 键 词：锂离子电池 正极材料 锂锰氧化物 尖晶石结构 氧缺陷 电化学性能 放电容量 

分 类 号：TM912.2[电气工程—电力电子与电力传动] O646.54[理学—物理化学]