Fabrication of high-performance gas diffusion electrode via microporous layer surface morphology control

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Enhancing the performance of membrane electrode assemblies (MEAs) that utilize gas diffusion electrodes (GDEs) to match those based on catalyst coated membranes (CCMs) is critical for the widespread application of GDE-based technologies in proton exchange membrane fuel cells (PEMFCs). The inferior interfaces between the catalyst layers and the proton exchange membranes (PEMs) within GDE-based MEAs result in lower performance. In this study, the microporous layer (MPL) surface morphology control was achieved through hot pressing possessing the advantages of convenient implementation and avoiding excessive ionomer introduction. This approach produces smoother surfaces and higher peeling strengths between GDEs and PEMs, indicating enhanced interfacial contact. The ohmic resistance decreased from 0.056 to 0.033 Ω cm2, while the cathode catalyst layer proton resistance decreased from 0.124 to 0.059 Ω cm2, suggesting that the proton conductivity across the layers and within the catalyst layers were both increased. Moreover, the catalytic activity and gas transport capability within the catalyst layers are marginally improved. Following the MPL surface morphology control, the peak power density of GDE-based MEA was improved by 23 %, comparable to that of the CCM-based MEA. Nevertheless, excessive hot-pressing pressure might block the water transport path, resulting in poor performance at high current density.