A low-cobalt AB5-type hydrogen storage alloy stabilized by an inert second phase for use in low-cost, high-performance NiMH cells

Abstract

Cost reduction of rechargeable nickel/metal hydride (NiMH) batteries is an important and challenging issue. We report here a multicomponent, low-cobalt AB5-type hydrogen storage alloy stabilized by an inert second phase for use in low-cost, high-performance NiMH batteries. X-ray diffraction and scanning electron microscopy measurements certify that the second phase is close to a Ni2Ti phase composition, while the main phase remains a hexagonal CaCu5 structure. It is demonstrated that the low-cobalt AB5-type hydrogen storage alloy can maintain good cycling stability as well as high hydrogen storage capacity up to 310-315 mAh/g, when stabilized by the secondary phase. © 2004 The Electrochemical Society.