Hydrogenation properties of a nonbreakable electrode made of ZrMn 0.6V 0.2Co 0.1Ni 1.2 and Ag

Abstract

An AB 2-type alloy ZrMn 0.6V 0.2Co 0.1Ni 1.2 was sintered with Ag powder to form a durable pellet. The aim is to fabricate a metal hydride electrode that can be rapidly charged with hydrogen gas and then discharged as an anode for Ni–hydride battery in electrolyte. The alloy in the pellet maintains the C15 Laves phase structure without forming a second phase. For the pellets Ag/AB 2=2.75 and 3, they retain their integrity after both gas-phase and electrochemical hydrogenation. It takes a longer time for the pellets to activate in hydrogen gas. After one cycle of hydrogenation, however, the hydrogenation rates become as fast as that of the pure alloy. The P–C–T curves of the pellets are also similar to those of the pure alloy, except the maximum hydrogen absorption capacities decrease slightly from H/M=1.2 to 1.0. The discharge capacities of the pellets vary from 220 to 315 mAhg −1, which are affected by the content of Ag, compact pressure, size of Ag flake, and charging time. The pellets have a potential application for charging in the gas phase and discharging in electrolyte.