Electrode Surface
Use the Electrode Surface node to model an electrochemical electrode-electrolyte interface between an electrolyte domain and an electrode boundary where the electrode is not included explicitly as a domain in the model geometry.
Use the Harmonic Perturbation section in conjunction with AC Impedance study types to control the perturbation amplitude in the frequency domain. The perturbation parameter is either Electric potential or Total current based on the Electrode phase potential condition selected in the next section.
Electrode phase potential Condition
This section specifies the potential in the electrode phase of the electrolyte-electrode interface. The electrode potential is used (via the overpotential) by the Electrode Reaction subnodes.
Use the Electric potential option (default) to set the value of the potential explicitly with respect to ground. The other option, Total current, adds an extra global degree of freedom for the potential in the electrode phase, set to comply with the chosen condition. When using the Total current option in 1D or 2D, the boundary area is based either on the Cross-Sectional Area (1D), or the Out-of-Plane Thickness (2D) properties, set on the physics interface top node.
Dissolving–Depositing Species
Use the settings of this section to define species that participate in dissolution-deposition electrode reactions, for instance metal deposition/dissolution or oxide formation.
Use the Add () and Delete () buttons as needed in the table to control the number of species. The name of each dissolving-depositing Species can be edited in the first column of the table.
The Molar volume, in conjunction with the reaction rates and stoichiometry, defined in the Electrode Reaction subnodes, determine the normal electrode growth rate. The growth rate can be used in conjunction with the Deforming Electrode Surface and Nondeforming Boundary multiphysics couplings to model geometry deformations.
When the Solve for species concentrations variables checkbox is selected, dependent variables for the molar surface concentration of the dissolving–depositing species are added. This also controls the option to set the Initial concentration of the species. The molar concentrations can be used to model the thickness of a dissolving/depositing layer in a time-dependent simulation where the resulting deformation in the model geometry is small and will have negligible impact on the current distribution. In stationary studies, the molar surface concentration variables will be defined but not solved for by default.
The Stoichiometric Coefficients section in Electrode Reaction and Reaction subnodes is used to set the stoichiometric coefficients for dissolving-depositing species.
Adsorbing–Desorbing Species
Use the settings of this section to define species that can adsorb or desorb on the electrode surface.
The Density of sites parameter will be used to set up the local surface mass balance equations for the fractional surface coverages.
Use the Add () and Delete () buttons as needed in the table to control the number of species. The name of each adsorbing–desorbing Species can be edited in the first column of the table.
The Stoichiometric Coefficients section in the Electrode Reaction and Reaction subnodes is used to set the stoichiometric coefficients for adsorbing–desorbing species reaction.