锂电池失效及材料界面能降低究因

通过参比电极检测钛酸锂(Li_4Ti_5O_(12))电池正负极充电时的电位变化,判定Li_4Ti_5O_(12)电池在55℃高温失效后的限容电极,并采用电子显微镜扫描(SEM)、X射线衍射(XRD)和Raman散射方法对限容电极失效原因进行分析。参比电极实验结果表明电池失效后的限容电极均为LiCoO_2正极。对比电池失效前后LiCoO_2正极的SEM图谱、XRD图谱和Raman图谱发现,化成LiCoO_2正极的晶粒出现裂纹和破裂,LiCoO_2表面已不具有层状结构,极片的嵌脱锂动力学受到影响。

Failure of lithium battery and reduction of material interface energy

The reference electrode was used in the positive and negative electrode of Li4Ti5O12 battery to check the charging point changes,determining the limited capacitance electrode of Li4Ti5O12 battery at a high temperature of 55 ℃.Scanning electron microscopy (SEM),X-ray diffraction (XRD) and Raman scattering method were used to analyze the failure reasons of limited capacitance electrode.The experimental results show that the limited capacitance electrode is positive electrode LiCoO2 when the battery is invalid.Contrasting the positive electrode SEM spectra,XRD and Raman spectra before and after the battery failure,it is found that the formation of LiCoO2 grains appears cracks and breakages.LiCoO2 surface has no layered structure,and the galvano-chemistry dynamics of lithium insertion and extraction are affected.