Massimiliano Cimenti

Investigation of Proton Transport in the Catalyst Layer of PEM Fuel Cells by Electrochemical Impedance Spectroscopy

The proton conductivity of the catalyst layer is an essential parameter for the design and optimization of PEM fuel cells cathodes. Few methods have been proposed to measure this quantity. In this study we tested two methods based on electrochemical impedance spectroscopy (EIS) measurements performed in H2/N2 and in H2/O2, respectively. The EIS H2/N2 method allows the quantification of the CL proton resistance at equilibrium, and in principle could be used to obtain catalyst layer microstructural information. The EIS H2/O2 method allows the quantification of both ohmic and CL proton resistances under load. According to our results, the EIS H2/N2 method is preferable because it is faster to perform, the data analysis is simpler, and provides the CL resistance at equilibrium.

Direct Utilization of Methanol on Ceria-based Anodes for SOFC

Ceria-based anodes containing nickel, copper, or copper-cobalt were tested for the direct utilization of pure methanol in solid oxide fuel cells at 1073 K. Cell performance and stability was determined at conditions favorable to carbon deposition to verify whether carbon deposits caused irreversible damage to the anodic microstructure. Results indicated that both pyrolysis and catalytic decomposition of methanol are important processes for direct utilization operation. Cell performance with methanol was similar or higher than with humidified hydrogen. Better performance with alcohol was a consequence of the improved electronic conductivity in the presence of carbon deposits. No significant micro-structural changes were detected on the anodes despite the formation of carbon.