CLOSED FORM SOLUTIONS TO INVESTIGATE IONIC CONDUCTIVITY IN POROUS FUEL CELL ELECTRODE MICROSTRUCTURES
Analytical closed form solutions have been developed to investigate the effect of 3-D fuel cell electrode material microstructure on ionic conduction. This is achieved using closed form solutions for potential and current of axisymmetric electrochemical fins with spherical, conical, and exponential geometries. The solutions were used to determine the effective ionic conductivity of real and ideal microstructures by constructing equivalent resistor, fin networks representing the original structures. The ionic conductivities computed with this method are compared to mesh-based finite simulations taking into account the detailed local structural inhomogeneities. Compared to finite simulations, the electrochemical fin method is able to predict ionic conductivities of the structures with reasonable accuracy. The electrochemical fin method also shows a significant decrease in computer memory and time requirements compared to the finite simulations for the structures analyzed. These results indicate that this method can be a valuable tool for the microstructural design of advanced electrodes with a focus on enhancing ionic conduction.