(Digital Presentation) Diagnostic Study of the Key Performance-Limiting Factors in Anion Exchange Membrane Fuel Cells

Abstract

Anion exchange membrane fuel cells (AEMFC) have received significant attention for their promised low production cost, largely enabled by the facile kinetics of the oxygen reduction reaction in alkaline electrolytes and the broader selection of potential ionomers.1,2 The performance of AEMFCs has been improved significantly by utilizing AEM with high ion exchange capacity (IEC) and optimizing membrane electrode structures.3 However, some fundamental issues limiting the performance of AEMFCs need to be better understood, especially the reaction kinetics at the catalyst-ionomer interface and the transport process at the multi-phase boundaries in the membrane electrode assembly (MEA).4,5 In this talk, we will present a systematic diagnostic study of the critical performance-limiting factors in AEMFC. We will discuss the reaction kinetics at the Pt/ionomer interface and the oxygen transport characteristics of the ionomer layer based on electrochemical data. In addition, we correlate the electrode pore structure, reaction kinetics, and mass transfer behavior with the cell performance based on the analysis of a series of MEA with varied multi-phase boundary designs. Further, experimental data will be presented with decoupled polarization behavior of both the anode and cathode of working AEMFCs. The results reveal that the deteriorated mass transport at the anode and the restricted reaction kinetic at the cathode are the crucial factors limiting the performance of AEMFC, which need to be addressed with high priority. References Wang, Y-J., Qiao, J., Baker, R., Zhang J. Chem. Soc. Rev., 2013, 42, 5768.Chen, N., Hu, C., Lee, Y. M. et al., Angew. Chem. Int. Ed. 2021, 60, 7710–7718.Huang, G., Mandal, M., Mustain, W. E., Kohl P. A. et al., J. Electrochem. Soc. 2019, 166, F637–F644.Dekel, D. R., J. Power Sources 2018, 375, 158e169.Jiang, H., Luo, R., Li, Y., Chen, W. EcoMat. 2022, 4, e12199. Acknowledgement Financial support from the National Key R&D Program of China (No. 2021YFB4001203) is greatly acknowledged.