可充碱锰电池循环容量衰降探因

Analysis of causes of capacity decline of rechargeable alkaline manganese battery during cycling

通过单电极放电曲线测试、X射线衍射分析、SEM分析等方法,研究了可充碱锰电池循环容量衰降的原因,并对可充碱锰电池容量衰降的立导因素及各因素之间的内在原因进行了分析.结果表明:可充碱锰电池的循环性能下降主要由负极造成;MnO2电极容量衰降的主要原因是水合锌黑锰石Zn2Mn4O8·H2O和KMnO2在正极中的形成和积累,以及正极的机械失效;Zn电极容量衰降的主要原因是锌粉颗粒聚集结块,以及负极区的电液干涸.

The cause of capacity decline of rechargeable alkaline manganese battery (RAM) during cycling was determined by means of the measurement of discharge curves of the positive and negative electrodes, and XRD and SEM. Experimental results show that the cycling performance decay of RAM is basically caused by the negative electrode. The main causes of capacity fade of MnO_2 electrode are the formation and accumulation of Zn_2Mn_4O_8·H_2O and KMnO_2in the positive electrode and the mechanical failure of the positive electrode. The capacity fade of Zn electrode is due to the aggregation of zinc particles, which induces the severe passivation of the electrode and the drying up of the electrolyte within the anode.