Copper corrosion appears slower at more negative potentials (Figure vs 5b), where 1) the cathodic field makes the formation of Cu and CO2 related complexes less favorable, 2) surface Cu oxide species that facilitate the formation of Cu-CO3 and Cu-HCO3-type species are less stable, and 3) the direct interaction of negatively charged anions with the surface becomes unlikely . Indeed, as observed in previous studies, the strong electrochemical driving force towards plating induces the formation of small re-plated copper particles observed at EWE < 0 V (Figure , Figure and Figure ) .