Ultrasonic process for the manufacture of proton exchange membrane fuel cell electrode assembly

The growing demand for clean energy underscores the importance of Proton Exchange Membrane Fuel Cells (PEMFCs) as a sustainable electricity generation solution. However, their widespread adoption faces challenges in performance, durability, cost, and manufacturing efficiency. This study investigates the ultrasonic process as a rapid alternative to traditional methods for manufacturing Membrane Electrode Assemblies (MEAs). Unlike the slow and complex hot pressing method, the ultrasonic process assembles MEAs in seconds without external heating. It transfers pre-coated layers to form the Catalyst Coated Membrane (CCM) and welds components like gas diffusion layers (GDL) without additional adhesives. This technique reduces assembly time by over 94 %, significantly enhancing production efficiency. Scanning Electron Microscope (SEM) analysis reveals that higher stress and energy input during the ultrasonic process decrease PTFE reinforcement thickness in the membrane (from 4.4 to 3.7 μm). Additionally, thanks to the SEM and X-ray tomography analyses, the weld quality is optimized by enabling detection and elimination of defects (distorted membrane, cracks and hole), ensuring defect-free interfaces. Initial fuel cell tests in 1.8 cm 2 differential cell and 20 cm 2 technical mono-cell, confirm that MEAs produced via the ultrasonic process perform similarly to those made with conventional techniques, under dry (<50 % RH) and wet (>80 % RH) conditions at 80 °C. In the 20 cm 2 cell at 0.8 V, both MEAs deliver identical current densities: 0.504 A/cm 2 (dry) and 0.305 A/cm 2 (wet). These results position ultrasonic process as a breakthrough in PEMFC manufacturing, offering a faster, more efficient process that supports the transition to clean energy. • Ultrasonic process reduces MEA assembly time by 94 %. • Successful electrode transfers with 4 cm 2 and 24.6 cm 2 sonotrodes. • Multilayer structures (up to 7 layers) assemblies validated with a 4 cm 2 sonotrode. • Electrochemical tests show ultrasonic CCMs match conventional ones.