The improvement in the cycle life of a metal-hydride electrode, LaNi3.35Co0.75Mn0.4Al0.3, brought about by the addition of ZnO to the alkaline electrolyte has been investigated using measurements based upon in situ electrical resistance. corrosion, scanning electron microscopy. X-ray photoelectron spectroscopy, X-ray diffraction and inductively-coupled plasma-atomic emission spectroscopy. It was found that Zn is underpotentially deposited on and subsequently alloyed with the subject electrode upon repeated charge-and-discharge cycles. The presence of Zn extends the cycle life of the LaNi3.35Co0.75Mn0.4Al0.3 electrode by inhibiting the disintegration and lowering the corrosion rate of the alloy particles.