铜在储氢合金表面包铜电极中的行为

Behavior of Copper in Hydrogen Storage Alloy Microencapsulated by Copper

在密封的电池体系中（即贫液状态），包铜储氢合金电极具有较好的抗氧化能力；而在强碱性溶液中（即富液状态），铜在电极工作的电位范围内（－１．１～－０．４Ｖ）具有一定的稳定性，但当扩展扫描范围（－１．１～－０．２Ｖ），将出现铜的氧化还原反应．随着充放电循环的进行，铜被氧化成Ｃｕ２Ｏ，进而形成ＣｕＯ２－２进入电解质（ＫＯＨ）溶液中，充电时又以Ｃｕ的形式于电极表面析出．针对这一现象，本文利用电位阶跃实验研究了ＣｕＯ２－２离子在镍电极上的电沉积过程。

Negative electrode made from Cu microencapsulated hydrogen storage alloy was studied by using cyclic voltammetry method. The results showed that copper as a coating material was of a certain stability in 5 mol/L KOH solution within the range of charge and discharge voltage. But when expanding the sweep voltage, the CV curve showed a pair of distinct oxidation reduction current peaks of Cu 2O formation at E =-0.3 V and Cu 2O reduction at E =-0.6 V. With charging discharging cycles, copper is liable to be oxidized to Cu 2O and further oxidized into CuO 2- 2. When charged again, CuO 2- 2 anion is reduced and Cu is electrodeposited on the sufrace of electroce. In respond to this phenomenon, the electrodeposition process of CuO 2- 2 on the smooth Ni electrode was studied by constant potential step technique. The results showed that the deposition process of copper followed the two dimension instantaneous mechanism.