Example: Simulation of Electrochemical Impedance Spectroscopy

Introduction This model treats a 1D investigation of a fuel cell cathode using Electrochemical Impedance Spectroscopy, or AC impedance. The effect of frequency and electrolyte conductivity is investigated. Firstly, the stationary problem is solved, and then for the frequency sweep, using the parametric solver.

Geometry

Domain equations, anode Electronic balance Ionic balance

Domain equations, cathode Electronic balance Ionic balance

Boundary conditions, anode at current feeder- anode interface at electrolyte- anode interface Boundary conditions, cathode at current collector- cathode interface at electrolyte- cathode interface

Domain equations, free electrolyte Boundary conditions, free electrolyte at electrolyte- anode interface at electrolyte- cathode interface

Nyquist Plot

Nyquist plot with changed conditions

Concluding remarks You have to firstly solve the stationary problem and then solve as many frequency sweeps as you like using the parametric solver. The fact that complex numbers can be entered into COMSOL Multiphysics makes this type of modeling unique to the FEA world.