Abstract
Advances in polymer electrolyte fuel cell (PEFC) electrodes have primarily focused on the development of novel catalyst and ionomer materials to overcome kinetic and mass transport limitations without fully considering how to best integrate these components into high performance electrode structures. Consequently, the PEFC performance can vary widely across electrodes with the exact same composition due to differences in the bulk and interfacial electrode structure. The difficulty of characterizing electrodes (especially the ionomer/catalyst interface) has limited our understanding of how process variables (e.g. ink formulation and electrode fabrication) influence electrode structure and performance. Using a suite of in situ electrochemical techniques, we describe how changes in the local ionomer distribution in Pt/Vu electrodes affects mass activity, Pt site accessibility, ionic conductivity, non-Fickian O2 transport, and ultimately PEFC performance across a series of ultrasonic sprayed and electrospun electrodes.[1,2] Finally, we'll summarize several approaches that have successfully employed to improve PEFC performance by controlling electrode fabrication and processing variables.
References
[1] T. Van Cleve, S. Khandavalli, A. Chowdhury, S. Medina, S. Pylypenko, M. Wang, K.L. More, N. Kariuki, D.J. Myers, A.Z. Weber, S.A. Mauger, M. Ulsh, K.C. Neyerlin, Dictating Pt-Based Electrocatalyst Performance in Polymer Electrolyte Fuel Cells, from Formulation to Application, ACS Appl. Mater. Interfaces. 11 (2019). https://doi.org/10.1021/acsami.9b17614.
[2] S. Kabir, T. Van Cleve, S. Khandavalli, S. Medina, S. Pylypenko, S. Mauger, M. Ulsh, K.C. Neyerlin, Toward Optimizing Electrospun Nanofiber Fuel Cell Catalyst Layers: Microstructure and Pt Accessibility, ACS Appl. Energy Mater. (2021). https://doi.org/10.1021/acsaem.0c03073.