MH-Ni电池循环衰退的电化学阻抗谱分析

Study on cycling deterioration of Ni MH battery by Electrochemical Impedance Spectroscopy(EIS)

采用电化学阻抗谱技术研究了ＭＨ－Ｎｉ电池早期循环衰退的主要原因。研究表明：ＭＨ－Ｎｉ电池早期循环衰退首先表现为电池的电压性能的降低，而后才是电池的电压性能和放电容量的迅速降低。电压性能的降低主要是由于隔膜逐渐变干造成电池溶液电阻Ｒｓ增加。

The main causes of cycling deterioration of Ni MH battery were studied by Electrochemical Impedance Spectroscopy (EIS). The results show that the early cycling deterioration of Ni MH battery firstly appeares as the voltage performance decrease, then follows by the sharp decrease of discharge capa city and voltage performance. The decrease of voltage performance is due to the drying of the separator which increases solution resistance R s of the battery, while the decrease of discharge capacity was due to the deactivation of electrode surface which increases reaction resistance R t of the battery.