Effect of CCM fabrication method on PEMFC performance: Spray-coated versus decal-transferred onto Aquivion® membranes

This study compares the electrochemical performance of proton exchange membrane fuel cells (PEMFCs) to analyze two innovative membrane-electrode assembly (MEA) fabrication processes: the spray catalyst-coated membrane (s-CCM) and the decal catalyst-coated membrane (d-CCM). In the s-CCM procedure, the catalyst ink is applied directly onto the membrane surface by spray coating procedure, followed by drying and hot pressing with the GDLs. In the d-CCM process, the catalyst ink is first deposited onto a PTFE substrate, which is then hot-pressed onto the membrane (decal); the PTFE substrate is subsequently removed, leaving the catalyst layer transferred to the membrane. Gas diffusion layers (GDLs) are then applied during final assembly. Polarization curves were recorded under various operating conditions, including temperatures ranging from 80 to 95 °C, relative humidity between 50% and 100%, and pressure from 1.5 to 3 bar, using hydrogen and air as reactant and oxidant gases, respectively. Under all test conditions, the d-CCM-MEA outperformed the s-CCM-MEA in terms of maximum power density, achieving a peak value of 1069 mW cm⁻² at 80 °C, 100% relative humidity, and 3 bar—approximately 65% higher than the s-CCM-MEA under the same operating conditions. This performance improvement is attributed to better catalyst–membrane interfacial contact, improved layer uniformity, and reduced mass transport resistance provided by the decal transfer process. These results highlight the significant influence of MEA fabrication on PEMFC performance and efficiency during operation.