Porous Conductive Binder
Use the Porous Conductive Binder node to define an electrochemically inactive but electronically conductive porous domains.
Use correction factors to account for the lowered diffusion coefficient and conductivity in the electrolyte and the lowered conductivities of the electrode, as a result of the lower volume fractions of each phase, and the tortuosity of the porous matrix.
You can specify the Nonfaradaic Reactions occurring on the domain as a subnode, which is available from the context menu (right-click the parent node) or from the Physics toolbar, Attributes menu. You can also add a Porous Matrix Double-Layer Capacitance subnode and, Dissolving-Depositing Species section in the porous conductive binder.
See also the Electrolyte and Current Conductor nodes for more information about the settings of this node.
Electrolyte Properties
See the Electrolyte node for more information about the settings of this section.
Electrode Properties
See the Current Conductor node for more information about the settings of this section
Porous Matrix Properties
The Electrode volume fraction εs and Electrolyte volume fraction ε1 parameters are used in the mass balance equations to account for the available volume of each phase. The default value for each fraction is 0.4. These parameter values may also be used by the Effective Transport Parameter Correction (next section). Similarly, the Electrode tortuosity τs and Electrolyte tortuosity τ1 parameters may also be used by the Effective Transport Parameter Correction (next section). Select either Isotropic to define a scalar value, or Diagonal and Symmetric to define anisotropic tensor values. The default is Isotropic 1.
Effective Transport Parameter Correction
Use the settings of this section to calculate effective transport parameters for the electrode and the electrolyte if your corresponding parameter values refer to nonporous media.
Dissolving-Depositing Species
Use the settings of this section to define species that participate in dissolution-deposition electrode reactions within the porous matrix of the binder, for instance, metal deposition/dissolution or oxide formation.
Use the Add () and Delete () buttons as needed in the tables to control the number of species.
Dependent variables for the volumetric molar concentration are added for each dissolving-depositing species.
The Density and Molar mass determine the electrode growth velocity and the resulting dissolved/deposited layer thickness. By multiplying by the electrode surface area (in the case of multiple electrode reaction the average surface area is used), the change in electrode and electrolyte volume fractions can be also be calculated. By use of the Add volume change to electrode volume fraction and Subtract volume change from electrolyte volume fraction checkboxes you may define how these volume changes should be included in the model.
Thickness variables, based on the surface area, are also defined that you for instance can use to couple to the Film Resistance (see below).
Film Resistance
A film resistance is typically used for modeling the build-up of a SEI (solid electrolyte interface) layer in lithium-ion battery graphite electrodes. This might be important for accounting the changes in electric conductivity of the electronic phase.
This physics node is available for the Lithium-Ion Battery and Battery with Binary Electrolyte interfaces.