The Effects of Gas Flow in Anode Channel and Within Anode Electrode on Electrochemical Impedance of Solid Oxide Fuel Cell

The purpose of the current study is to investigate the effects of gas flow in anode channel and within anode electrode on concentration impedance of a solid oxide fuel cell. The gas phase mass transport is modelled using transient conservation equations (momentum and species equations). Results show that gas flow and mass transport in the gas channel results in a depressed semicircle in the Nyquist plot with low relaxation frequency (less than 10Hz). In addition, gas transport in the thick porous anode leads to a Warburg diffusion impedance with relatively higher relaxation frequency (around 100Hz). The influences of parameters such as inlet gas velocity, electrode thickness and inlet gas compositions are also investigated and the results are discussed. From the simulation results, it is found that the EIS simulation produces a tool for both analysing experimental results of EIS and performance optimization of fuel cells. In addition, the developed simulation tool may allow for a reduction in the amount of costly trial and error experiments.