Nickel electrode expansion and the effect of LiOH additive

The expansion of a nickel electrode with cycling is studied quantitatively using an electrode bending technique. The rate of electrode bending correlates well with the reported rate of thickness expansion of the electrode. A quantitative relationship between the electrode expansion rate and the depth-of-discharge of cycling is discussed. The presence of a small amount of LiOH added to a KOH electrolyte reduced both the irreversible expansion of the electrode with cycling and the amplitude of the contraction-expansion within a single charge-discharge cycle.