覆钴Ni(OH)_2电极在充放电循环过程中的结构变化

Structure change of nickel hydroxide electrode encapsulated by cobalt during charge-discharge cycles

β-Ni(OH)2在高倍率充电或过充电时容易转化为γ-NiOOH,引起电极膨胀、变形,从而影响电池的性能和寿命。在β-Ni(OH)2微粒表面化学覆钴后能改善电极的性能,通过X射线衍射(XRD)研究发现,化学覆钴后的β-Ni(OH)2电极在充放电循环过程中其γ-NiOOH的产生能得到明显抑制;扫描电子显微镜(SEM)测试发现充放电循环后β-Ni(OH)2微粒的粉化明显减少。

β-Ni（OH）2 can easily be transferred into γ-NiOOH when charged at high rate or overcharged, which results in deformation and swelling of the electrode, and thus being detrimental to the battery performance. Electroless cobalt depositing on the surface of spherical nickel hydroxide particles was demonstrated to improve the characteristics of the nickel hydroxide electrode. In present study we found that the formation of γ-NiOOH could be markedly inhibited and pulverization of β-Ni（OH）2 could be apparently reduced during charge-discharge after electro-less cobalt was deposited by XRD and SEM analysis.