The Memory Effect in the Partial Charge-Discharge Cycling of Alkaline Secondary Batteries

We observed the memory effect, the working voltage lowering, which occurred due to the repeated partial charge-discharge cycling of a Ni-capacity-limited alkaline cell, for example 50–70% state of charge, and γ-NiOOH in the Ni electrode was identified as the cause of the memory effect. During this condition, γ-NiOOH is proposed to be formed by partial overcharging due to the heterogeneity of the conductive materials such as cobalt compounds in the Ni electrode. Using nano-sized conductive materials homogeneously dispersed in the electrode leads to a significant effect on the suppression of the memory effect occurring due to the repeated partial charge-discharge cycling.