Understanding Ion-Transfer Reactions in Silver Corrosion and Electrodeposition

The electrified aqueous/metal interface is critical in controlling the performance of energy conversion and storage devices, but an atomistic understanding of even basic interfacial electrochemical reactions challenges both experiment and computation. We report an experiment study of (reversible) ion-transfer reactions involved in anodic Ag corrosion, a model system for interfacial electrochemical processes generating or consuming ions by using temperature-dependent voltage-step measurements. The experimental activation energies (0.4 eV) and transfer coefficients agree with the calculated (equilibrium) free-energy barriers (0.2 eV). The use of Ag nanoclusters eliminates the convolution of the kinetics of Ag + (aq.) generation and transfer with those of nucleation or etch-pit formation. The work, coupled with theoretical studies, provides molecular-level details on the nascent Ag + ion formation as well as the primary factors controlling the energetics of the reactions in broad relevance across the energy sciences.