Engineering and Testing of CCM Modifications for Improved Operational Flexibility, Durability and Performance of Fuel Cells and Electrolyzers

The performance, durability and cost of PEM fuel cell and electrolyzer systems still requires further improvements before they can be widely adopted. Along with improved electrocatalysts, low cost interface modifications and intermediate layers are important to improve the operation of catalyst coated membranes (CCMs) and meet commercial requirements. In this presentation we present some examples of the modification of conventional commercial CCM and MEA modifications with performance benefits. This would include for example the effect of improving the microporous layer (MPL) / catalyst layer (CL) interface by reducing the gaps to improve power density1, the improvement of cross-over and operational flexibility with a thin electrolessly deposited catalyst layer at the membrane surface 2, and modification of the porous transport layer (PTL) / catalyst interface3. A new testing method for the evaluation of commercial CCMs was used in this work which can accelerate design and testing of these new and modified CCMs. This new method uses a Modified Rotating Disk Electrode (MRDE)4 which allows electrodes and CCMs to be tested up to high current densities, e.g., 2 A/cm2, and eliminates the variability and issues associated with thin film RDE testing. Figure 1 shows an example of testing the oxygen evolution reaction (OER) performance for different PTLs with a commercial CCM using the MRDE. The MRDE testing is also useful for carrying out accelerated degradation (ADT) testing of CCMs for fuel cell or electrolyzer applications5 and has the potential to be used as a quality control tool for CCM manufacturing lines. References: L. Daniel, A. Bonakdarpour and D.P. Wilkinson, Fuel Cells, 20(2), F1-F7 (2020) L.Daniel, A. Bonakdarpour and D.P. Wilkinson, ACS Applied Nano Materials, 2, 3127-3137 (2019); J. of Power Sources, 471, 228418 (2020) M. Kroschel, A. Bonakdarpour, J.T.H. Kwan, P. Strasser and D.P. Wilkinson, Electrochim. Acta, 317, 722-736 (2019) J. T. H. Kwan, A. Bonakdarpour, G. Afonso, and D. P. Wilkinson, Electrochim. Acta, 258, 208–219 (2017). P.J. Petzold, J.T.H. Kwan, A. Bonakdarpour, and D.P. Wilkinson, J. Electrochem. Soc., 168(2), 026507 (2021) Figure 1: The effect of different titanium current collector meshes on OER performance using a commercial IrO2-based CCM obtained by the MRDE tool. Inset shows the pictures of different Ti meshes examined. Figure 1