IMX Seminar Series - Reversible Electrochemical Cells for Fuel to and from Electricity

Over the past decade, the availability of electricity from sustainable energy sources has risen dramatically while the cost has fallen steeply. These factors have driven a surge in activity in the development of energy storage technologies. While much of this effort has been directed towards photocatalytically generated solar fuels and grid-scale batteries, reversible hydrogen electrochemical cells offer untapped opportunities. In particular, electrochemical cells based on proton conducting ceramic oxides are attractive candidates for interconversion between hydrogen and electricity. The proton conducting nature of the electrolyte provides inherent advantages in the gas flow configuration over traditional solid oxide cells in which the electrolyte is an oxygen ion conductor. We describe here recent progress in reversible protonic ceramic cells achieved using a combination of three advances: a new electrolyte composition, a new air electrode, and processing methods to decrease the contact resistance between these two components. The resulting cells display exceptional performance in both fuel cell and electrolysis modes. In the latter case, conversion efficiency suffers a small penalty due to slight electronic leakage across the cell. The cells are extremely stable over hundreds of hours of operation and dozens of cycles between electricity generation and hydrogen production. As such, protonic ceramic electrochemical cells are likely to play a major role in a sustainable energy future.
Bio: Sossina M. Haile is the Walter P. Murphy Professor of Materials Science and Engineering at Northwestern University, a position she assumed in 2015 after serving 18 years on the faculty at the California Institute of Technology. She earned her Ph.D. in Materials Science and Engineering from the Massachusetts Institute of Technology in 1992. Haile’s research broadly encompasses materials, especially oxides, for sustainable electrochemical energy technologies. She has established a new class of fuel cells with record performance for clean and efficient electricity generation, and created new thermochemical approaches for harnessing sunlight to meet rising energy demands. Amongst her many awards, in 2008 Haile received an American Competitiveness and Innovation (ACI) Fellowship from the U.S. National Science Foundation in recognition of “her timely and transformative research in the energy field and her dedication to inclusive mentoring, education and outreach across many levels.” She is a fellow of the Materials Research Society, the American Ceramics Society, the African Academy of Sciences, and the Ethiopian Academy of Sciences.