金属氢化物电极和金属氢化物/镍电池的电化学阻抗谱

ELECTROCHEMICAL IMPEDANCE SPECTROSCOPIC STUDY ON METAL HYDRIDE ELECTRODE AND METAL HYDRIDE/NICKEL BATTERIES

用电化学阻抗谱 (EIS)方法 ,对金属氢化物 (MH)电极和两种商品化金属氢化物 /镍(MH/ Ni)电池性能进行了研究 .通过建立等效电路模型分析了 MH电极的电化学阻抗谱 .结果表明 ,在不同放电深度和充放电循环时 ,电极的欧姆阻抗、反应电阻和界面电容等呈规律地变化 ,并与电极性能的变化相一致 .欧姆阻抗和由制备工艺带来的电极反应性能的差别 ,是引起两种商品化 MH/ Ni电池电化学充放电性能差别的主要原因 .也说明 ,EIS可用于检测 MH电极的荷电状态和反应性能 ,并可作为在线无损伤 MH/ Ni电池性能测试技术 .

The performances of the metal hydride (MH) electrodes and metal hydride/nickel (MH/Ni) batteries were investigated by using electrochemical impedance spectroscopic technique (EIS).The results showed that the proposed equivalent circuit model was successfully fitted to the EISs of MH electrodes,the ohm resistance,reaction resistance and interface capacitance of MH electrodes changed progressively with the increase of the depth of discharge and charge-discharge cycles.They were consistent with the performance degradation of MH electrodes.The differences of ohm resistace and reaction resistance,which arose from the construction method,gave rise in the performance differences of two kinds of commercial MH/Ni batteries.In addition,it is also concluded that EIS can be used to forecast the state of charge and performance of MH electrodes,and will be a power in-situ and non-destructive evalution tool for the performance of MH/Ni battery.