THE MECHANISM OF ELECTRODEPOSITION AND OPERATION OF NI(OH)(2) LAYERS

It is well-known that uniform layers of Ni(OH)(2) can be formed by cat hodic electrochemical deposition. The product phase Ni(OH)(2) is predo minately an ionic conductor, not an electronic conductor. This means t hat the electrochemical reaction must occur underneath the ionic condu ctor at the substrate/Ni(OH)(2) interface, whereas the formation of th e hydroxide layer takes place at the Ni(OH)(2)/electrolyte interface. A model of a growth mechanism requiring the transport of several speci es through the growing product layer to the Ni(OH)(2)/electrolyte inte rface is discussed.