Unexpected Performance of Inkjet Printed Membrane Electrode Assemblies for Proton Exchange Membrane Fuel Cells

The effect of the deposition substrate on the performance of inkjet-printed membrane electrode assemblies (MEAs) is investigated. MEAs are fabricated from inkjet-printed catalyst-coated membranes (CCMs), gas diffusion electrodes (GDEs), and a bilateral sandwich of a CCM and a GDE. All MEAs are tested in proton exchange membrane fuel cells (PEMFCs). When a hot-pressing step is included in the MEA construction, the power density achieved with the GDE-based MEA is 1.067 W cm(-2), exceeding that achieved with the CCM-based MEA (0.579 W cm(-2)), and the bilateral sandwich MEA (0.792 W cm(-2)). The origin of the superior performance of the inkjet-printed GDE-based MEAs is investigated through electrochemical impedance spectroscopy and analysis of the microstructure of the printed membranes and electrodes. Atomic force microscopy and energy dispersive X-ray spectroscopy suggest that the greater surface and interfacial areas of the GDE-printed catalyst layer may drive the unexpectedly high performance of the GDE-based MEA as compared with its CCM and bilateral sandwich counterparts. These results provide new insights into the connections between the substrate, inkjet-printed catalyst layer microstructure, and catalyst utilization.