负极表面镀镍对镍氢电池循环寿命与内部压强的影响

Effect of nickel electroplating on negative electrode surface on cycle life and inner pressure of nickel hydride battery

采用含有240g/LNiSO4·7H2O、40g/LH3BO3、50g/LC6H5Na3O7·2H2O的镀液,在镍氢电池的负极表面电沉积上一层厚度约为0.1μm的镍层。镀镍修饰后,负极材料的电化学特性发生了明显变化,如极化电阻显著降低,使得水在负极材料上放电更加容易,改善了镍氢电池的充电行为。使用表面镀镍的负极材料后,镍氢电池的内部压强在正常充电与过充过程中都显著降低,这可能是因为镀镍层减缓了氢原子结合而变成氢气的过程;另外,镍氢电池的循环寿命也得到了延长。

A nickel coating with a thickness of ca.0.1μm was electrodeposited on the negative electrode of Ni-MH battery in a bath containing 240 g/L NiSO4·7H2O, 40 g/L H3BO3, and 50 g/L C6H5Na3O7·2H2O. The electrochemical properties of the negative electrode material are significantly changed by the modification with nickel coating. The polarization resistance of the nickel-plated negative electrode is decreased evidently, which facilitates the discharging of water on the electrode and improves the charging behavior of Ni-MH battery. The inner pressure of Ni-MH battery is decreased remarkably by using nickel-plated negative electrode during normal charging and over-charging processes, likely due to the adsorption of H atoms on nickel coating which slows down the combination of H atoms into H2 gas. The results also showed that the Ni-MH battery with nickel-plated negative electrode has a longer cycle life.