Effects on the positive electrode of the corrosion of AB5 alloys in nickel-metal-hydride batteries

Effects of corrosion of MmNi(4.3-x)Mn(0.3)Al(0.4)Co(x) alloys are evaluated in nickel-metal-hydride (Ni-MH) cells. Particularly, it is shown how Al released by the corroded alloys pollutes the positive electrode, which endures a loss of charging efficiency, due to the formation of an hydrotalcite-like phase stabilized with Al. Furthermore, since Al is eluted from the hydride electrode and is completely trapped in the positive active material, the titration of this element in the positive electrode is a powerful technique for quantification of the corrosion of AB(5) alloys in Ni-MH cells.