Tertiary Current Distribution, Nernst–Planck
Now set up the electrochemical model, which consists of an electrolyte domain and two electrode boundaries.
Define the Electrolyte Properties
1
In the Model Builder locate the Tertiary Current Distribution, Nernst–Planck node, then click Species Properties 1 .
2
Under Charge, replace the defaults with the following:
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In the zcCu text field, enter z_Cu.
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In the zcSO4 text field, enter z_SO4.
3
Under the Tertiary Current Distribution, Nernst–Planck node, click Electrolyte 1
4
Under Diffusion, replace the defaults with the following:
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In the DcCu text field, enter D_Cu.
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In the DcSO4 text field, enter D_SO4.
 
Define the Electrode Surface and Electrode Reaction Nodes
1
In the Physics toolbar click Boundaries  and choose Electrode Surface .
2
In the Settings window for Electrode Surface under Boundary Selection, from the Selection list select Boundary 3.
3
An easy way to facilitate choosing this electrode surface later is to create a selection here. To do so, click the Create Selection button and type Anode in the Selection name text field of the Create Selection dialog that appears.
4
In the Settings window for Electrode Surface, click to expand the Dissolving-Depositing Species section.
5
Click Add.
6
Under Species in the Dissolving-Depositing Species table, enter cdep_anode (replace the default).
7
Under Electrode Phase Potential Condition in the text field, enter phis_anode.
8
Expand the Electrode Surface 1 node then click Electrode Reaction 1 .
9
Under Stoichiometric Coefficients:
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In the Number of participating electrons n text field, enter 2.
10
Under Electrode Kinetics:
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From the Kinetics expression type list, choose Butler–Volmer.
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From the Exchange current density type list, choose Mass action law.
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In the Reference exchange current density i0,ref text field, enter i0_ref.
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In the Anodic transfer coefficient αa text field, enter alpha_a.
Define the Second Electrode Surface and Electrode Reaction Nodes
Duplicate the anode node to create the settings for the cathode.
1
In the Model Builder window, right-click Component 1 (comp1) > Tertiary Current Distribution, Nernst–Planck (tcd) >Electrode Surface 1 and choose Duplicate.
2
In the Settings window for Electrode Surface under Boundary Selection, select Boundaries 2, 4-7, and 9-12. The easiest way to do this is to first select All boundaries in the Selection list, and then to deselect the top and side boundaries.
3
Create a selection for this electrode surface as well. Click the Create Selection button and type Cathode in the Selection name text field of the Create Selection dialog that appears.
4
Under Species in the Dissolving-Depositing Species table, enter cdep_cathode.
5
Under Electrode Phase Potential Condition in the text field, enter phis_cathode.
Define the Initial Values
1
Click the default Initial Values 1 node.
2
In the Settings window under Initial Values and in the cSO4 text field, enter Cinit.
Define the Temperature
Set up the temperature value used in the entire model.
1
In the Model Builder window, under Global Definitions click Default Model Inputs and locate the Browse Model Inputs section.
1
In the tree, select General > Temperature (K) - minput.T.
2
Find the Expression for remaining selection subsection. In the Temperature text field, type T0.