An indicator of zinc morphology transition in flowing alkaline electrolyte

Changes in electrodeposited zinc morphology were experimentally investigated in a flowing alkaline electrolyte. Deposition of zinc on flat sheets as well as on new mesh-type reduced-area current collectors was studied. Zincate concentration in the electrolyte, flow velocity, and current density was varied over a wide range. The results show that the ratio between the effective current density and the limiting current density (current density ratio) which is directly related to the zincate concentration at the electrode surface determines the zinc morphology. Zinc morphology is mossy and porous when the current density ratio is below 0.4, whereas it is a mixture of mossy and crystalline structures when it is between 0.4 and 0.9. Only when the current density ratio is above 0.9, does zinc deposition become just crystalline and compact. This finding holds for both flat sheet and mesh-type reduced-area current collectors.