Abstract
Cracks in catalyst layers (CLs) are a potential source of long-term failure in a fuel cell membrane electrode assembly (MEA). While modifications to the CL ink formulation can affect the degree of cracking, these changes may lead to lower initial performance than their cracked analogues due to the established link between formulation and performance. In this work, we explored the use of polymeric additives to mitigate CL cracks. Small quantities of poly (acrylic acid), poly (ethylene oxide), poly (methyl methacrylate), or poly (vinyl alcohol) – 5 wt% relative to ionomer mass – were added to the ink prior to its final mixing. Poly (vinyl alcohol) resulted in crack–free CLs, whereas the other polymers resulted in CLs with similar crack percentages as the control CL. Through a combination of transmission electron microscopy, X-ray computed tomography, and infrared spectroscopy, we ascribed the crack–mitigating mechanism of poly (vinyl alcohol) to its ability to hydrogen–bond with Nafion, the ion conducting polymer binder in the catalyst ink. Initial performance of this non–cracked electrode exhibited nearly identical electrochemical behavior to its cracked counterpart, demonstrating that PVA additives successfully reduce cracks while maintaining cell initial performance.
| Original language | English |
|---|---|
| Article number | 233852 |
| Journal | Journal of Power Sources |
| Volume | 592 |
| DOIs | |
| State | Published - Feb 1 2024 |
| Externally published | Yes |
Funding
This work was authored in part by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. These experiments are based on work performed by the Million Mile Fuel Cell Truck (M2FCT) Consortium, technology managers Greg Kleen and Dimitrios Papageorgopoulos. Funding provided by U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Hydrogen and Fuel Cell Technologies Office. The authors recognize the Energy Systems Integration Facility (ESIF) and the Solar Energy Research Facility (SERF) operations team at NREL for enabling this research. This research used resources of the Advanced Photon Source (APS), a U.S. Department of Energy Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Argonne National Laboratory is managed for the U.S. Department of Energy by the University of Chicago Argonne, LLC, also under contract DE-AC-02-06CH11357. The authors would like to thank Viktor Nikitin of beam line 32-ID, APS. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. The authors would like to thank Kimberly S. Reeves for assistance with ultramicrotomy sample preparation and SEM measurements. The Talos F200X S/TEM tool provided by US DOE, Office of Nuclear Energy, Fuel Cycle R&D Program, and the Nuclear Science User Facilities. This work was authored in part by the National Renewable Energy Laboratory , operated by Alliance for Sustainable Energy , LLC , for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308 . These experiments are based on work performed by the Million Mile Fuel Cell Truck (M2FCT) Consortium , technology managers Greg Kleen and Dimitrios Papageorgopoulos. Funding provided by U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Hydrogen and Fuel Cell Technologies Office . The authors recognize the Energy Systems Integration Facility (ESIF) and the Solar Energy Research Facility (SERF) operations team at NREL for enabling this research. This research used resources of the Advanced Photon Source (APS) , a U.S. Department of Energy Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357 . Argonne National Laboratory is managed for the U.S. Department of Energy by the University of Chicago Argonne, LLC , also under contract DE-AC-02-06CH11357 . The authors would like to thank Viktor Nikitin of beam line 32-ID, APS. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes.
| Funders | Funder number |
|---|---|
| M2FCT | |
| Million Mile Fuel Cell Truck | |
| Solar Energy Research Facility | |
| U.S. Government | |
| University of Chicago Argonne, LLC | DE-AC-02-06CH11357 |
| U.S. Department of Energy | DE-AC36-08GO28308 |
| U.S. Department of Energy | |
| Office of Science | |
| Argonne National Laboratory | DE-AC02-06CH11357 |
| Argonne National Laboratory | |
| National Renewable Energy Laboratory | |
| Hydrogen and Fuel Cell Technologies Office |
Keywords
- Catalyst layer
- Critical crack thickness
- Electrode imaging
- Formulation-process-performance relationships
- Mayer rod coating
- Polymer additives
