Electrodissolution of zinc at the limiting current

The mass-transfer-limited region of zinc electrodissolution in alkaline electrolyte was investigated using a zinc rotating disk electrode. Pseudo-steady-state polarization measurements reflect a strong dependence of dissolution rate and shape of the limiting current plateau on composition and mass transfer rate. Electrochemical impedance spectroscopy results show that there is no appreciable dependence of the high frequency resistance on potential or rotation speed at prepassive potentials. Electrohydrodynamic impedance measurements, together with a simple model, suggest that the zincate ion is the appropriate mass transfer-limited species in this range, although the diffusion coefficients estimated from these analyses are lower than expected. (C) 2001 The Electrochemical Society.