Using a specially designed device, the ionic conductivity was determined for single beads of spherical NiOH in KOH solutions. The apparent ionic conductivity was found to be of the order of 10-3 to 10-2S/cm in 6M KOH, and to change with the conductivity of the solution in which the bead was immersed. The ionic conductivity of the bead could be attributed mainly to the electrolyte absorbed in the bead. On the basis of the results, the dual-structure model for proton diffusion in spherical NiOH was refined by specifying nanoparticles to be the component which exhibited a large apparent proton diffusion coefficient; of the order of 10-7cm2/s. The refined model was able to explain the main features of the reported diffusion coefficients; including the unusually large scattering (up to 6 orders of magnitude) and an inconsistency in the dependence of proton diffusion

coefficient upon the state of the charge. This refined model was supported by the influence of bulk KOH concentrations upon chronoamperometry and transmission electron microscopy observations.

Determination of Ionic Conductivity and its Impact on Proton Diffusion Model for Nickel Hydroxide. L.Xiao, J.Lu, P.Liu, L.Zhuang: Journal of Physical Chemistry B, 2006, 110[5], 2057-63