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 multicomponent Zr(V(0.)2Mn(0.2)Ni(0.6-x)Co(x))(2.4) alloys have been investigated as a negative electrode in the metal hydride batteries. The crystal structure turned out to change as a function of substituted cobalt from a cubic C15 type structure to a hexagonal C14 type structure. There were anomalies in the relation among the hydrogen plateau pressure 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) electrode was used to evaluate the electrochemical characteristics including activation, cycle life, electrocatalytic activity and hydrogen adsorption. 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 Association for Hydrogen Energy.