As electronic products have come to feature more sophisticated functions, more compact sizes and lighter weights, the sources of power that operate these products have been required to deliver increasingly higher levels of energy. To meet this requirement, nickel-metal hydride batteries have been developed and manu-factured with nickel hydroxide for the positive electrode and hydrogen-absorbing alloys capable of absorbing and releasing hydrogen at high-density levels for the negative electrode. Compared to Ni-Cd batteries, Ni-MH batteries have about twice the energy density and a similar operating voltage.