STRUCTURE AND ELECTROCHEMICAL PROPERTIES OF ZR(V0.2MN0.2NI0.6-XCOX)(2.4) HYDROGEN STORAGE ALLOYS

The structure and hydrogen absorbed properties of a series of the mult icomponent Zr(V(0.)2Mn(0.2)Ni(0.6-x)Co(x))(2.4) alloys have been inves tigated as a negative electrode in the metal hydride batteries. The cr ystal structure turned out to change as a function of substituted coba lt from a cubic C15 type structure to a hexagonal C14 type structure. There were anomalies in the relation among the hydrogen plateau pressu re from PCT, electro nic factor of the alloy and A(2)B(2) tetrahedral interstice for hydrogen occupation. The Zr(V0.2Mn0.2Ni0.5Co0.1)(2.4) e lectrode was used to evaluate the electrochemical characteristics incl uding activation, cycle life, electrocatalytic activity and hydrogen a dsorption. II was found that both the hydrogen adsorption process and hydrogen diffusion process took place in the electrochemical impedance spectra of the electrode used here. (C) 1998 International Associatio n for Hydrogen Energy.