Cause of Memory Effect Observed in Alkaline Secondary Batteries–AC Impedance Analysis

The cause of the memory effect observed in alkaline-type rechargeable batteries was studied. It is found that γ-NiOOH initially forms at the collector side and it grows to the solution side as shallow charge-discharge cycling progresses. The charge transfer resistance of the charged-state Ni-electrode increases with shallow charge-discharge cycling. These results suggest that the memory effect is mainly caused by the formation of γ-NiOOH.