Composition optimization for cathode catalyst layer of PEM fuel cell based on percolation relations

'Full text': The optimization of the cathode catalyst layer of polymer electrode membrane (PEM) fuel cell has been numerically discussed based on the available cathode catalyst layer model and percolation theory. One, two or all of the three design parameters, Pt loading, catalyst layer thickness and Nafion content, is/are respectively taken as the optimization variable(s) to conduct the corresponding optimization analysis. The optimization results of the case when only Pt loading is considered as the optimization parameter are compared with the experimental data carried out by C. C. Boyer et al at different cell potentials. Numerical optimization shows that when the optimization variables do not include both of the catalyst layer thickness and Pt loading, the optimum point lies in the interior of the feasible design region, but when the optimization variables do include both of the thickness and Pt loading, the optimum point occurs on the upper boundary of the thickness. Further analysis indicates that, when all of the three parameters are taken as optimization variables, the maximum current density is much better than that when one or two of the three parameters is/are taken as the optimization parameter(s). (author)