A study on the swelling of a sintered nickel hydroxide electrode

The swelling and blistering of a sintered nickel hydroxide electrode, which usually determine the life of the electrode, have been found to be dependent on the the change in the density of the active material during charge and discharge. In particular, the swelling after cycling has been related to the degree of formation of -NiOOH. The largest swelling, as represented by an increase in the thickness of the electrode, occurs when -NiOOH changes to -NiOOH during charging rather than discharging. Addition of cadmium, zinc and magnesium is effective in preventing the formation of -NiOOH. In particular, the swelling can be almost completely prevented by addition of cobalt and cadmium together, even with overcharging at the 1 C rate.