Nonequilibrium Interface Dynamics:
Hierarchical Modeling and Multiscale Simulation of Materials Interfaces

CSIC Building (#406), Seminar Room 4122.
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Phase Field Modeling of the Electrochemical Interface

Dr. Jonathan Guyer

Metallurgy Division at NIST

Abstract:   We examine the kinetic behavior of a phase field model of the electrochemical interface in one dimension. We have previously shown that the equilibrium properties of this model (surface energy, surface charge, and differential capacitance) bear stronger resemblance to experimental measurements than to the predictions of existing sharp-interface models. For electrodeposition and electrodissolution conditions, using a single set of governing equations, we demonstrate ohmic conduction in the electrode and ionic conduction in the electrolyte. We find that, despite making simple, linear dynamic postulates, we obtain the nonlinear relationship between current and overpotential predicted by the classical "Butler-Volmer" equation and observed in electrochemical experiments. The charge distribution in the interfacial double layer is affected by the passage of current and, at sufficiently high currents, we find that the diffusion limited deposition of a more noble cation leads to alloy deposition with less noble species.