Materials Mitigation Strategies and Anode Catalyst Durability in Low Temperature Electrolysis

Abstract

Hydrogen has unique advantages as an energy carrier, with a high energy density and capacity to facilitate both long term storage and conversion between electricity and chemical bonds. Although hydrogen currently has a significant role in transportation and agriculture, its use in the general energy landscape has been limited. With decreasing electricity prices, electrolysis cost reductions can be achieved and will enable an opportunity for greater use.[1] While load-following renewable power sources can reduce feedstock costs, further cost reductions can be achieved by reducing the platinum group metal (PGM) content.[2]Efforts are needed and underway to understand electrolyzer degradation and develop accelerated stress tests when accounting for lower PGM loadings and intermittent operation. In this presentation, studies related to different catalysts and catalyst layer properties, and their impact on electrolyzer performance and durability will be discussed. Catalysts with high metal content and less stable elements were generally found to be more susceptible to mobility and migration.[3] Materials have been evaluated, however, that can address catalyst degradation. These include catalyst development strategies such as crystallinity, structured morphologies, and supports, and electrode design strategies such as coating techniques and pore formers. In some cases this has led to increased site utilization and the spread of operational stressors through a larger portion of the catalyst layer, lessening performance losses over time. Testing of these materials has included more continuous operation and with applied accelerated stress tests, and it was found that certain materials may address load fluctuations in different ways. Perspectives on anode catalyst development will be discussed as they relate to the current status of materials mitigation strategies and anode catalyst layer degradation.[1] B. Pivovar, N. Rustagi and S. Satyapal, The Electrochemical Society Interface, 27, 47 (2018).[2] K. Ayers, N. Danilovic, R. Ouimet, M. Carmo, B. Pivovar and M. Bornstein, Annual Review of Chemical and Biomolecular Engineering, 10, 219 (2019).[3] Pivovar, B. S.; Boardman, R., H2NEW: Hydrogen (H2) from Next-generation Electrolyzers of Water. 2022.Acknowledgements: This research is supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office under the auspices of the H2NEW consortium. Electron microscopy was performed at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility at Oak Ridge National Laboratory. The X-ray spectroscopy experiments were performed at beamline 10-ID at the APS, which is operated by the Materials Research Collaborative Access Team (MRCAT). MRCAT operations are supported by the Department of Energy and the MRCAT member institutions. The APS is a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.