CV curves of EDL

Dear all,

I am trying to simulate the CV curves of EDL without electrode reactions. I combined Electrostatic and Eletroanalysis modules to do the simulation. To define the stern layer, I introduced the boundary of surface charge density in the Electrostatic model. However, I can not get the correct CV curves. Can anyone help me with the probloem? Thank you. My .mph file is attached.

Best, Chi