Characterization of the copper/electrolyte interface on two copper conductors under high voltage

The effect of a high applied voltage up to 30 V between two copper conductors is investigated in a 0.05 mol L−1 sodium chloride solution. It appears that the potential is mainly applied to the anode/electrolyte interface and that, after a fast decay, the overall current density reaches a constant value, which is independent of the applied potential. This “passive” behaviour is attributed to the formation of a copper(I) chloride layer at the surface of the anode that limits the dissolution rate of copper in the electrolyte. It is shown that electromigration of chloride ions trough the CuCl layer controls the overall anodic reaction.