Joint Meeting

David Turnbull Lectureship Presentation featuring Sossina Haile

Thursday, December 3
5:15 pm – 6:15 pm

Join us for the David Turnbull Lectureship presentation featuring Sossina Haile, Walter P. Murphy Professor of Materials Science and Engineering at Northwestern University.

The David Turnbull Lectureship recognizes the career contribution of a scientist to fundamental understanding of the science of materials through experimental and/or theoretical research. In the spirit of the life work of David Turnbull, writing and lecturing also can be factors in the selection process.

Sossina M. Haile is honored "For fundamental contributions to the electrochemical and thermochemical materials science that advance sustainable energy, for her commitment to the broader international materials community and for being an inspiring colleague and passionate mentor".


Sossina HaileSossina M. Haile, Northwestern University
Superprotonic Solid Acids for Sustainable Energy Technologies

The compound CsH2PO 4 has emerged as a viable electrolyte for intermediate temperature fuel cells. This material is a member of the general class of compounds known as solid acids or acid salts, in which polyanion groups are linked together via hydrogen bonds and monoatomic cations provide overall charge balance. Within this class, several solid acids display a superprotonic transition, at which the compound transforms to a structurally disordered phase of high conductivity. At the transition the conductivity jumps by 3-5 orders of magnitude and the activation energy for proton transport drops to a value of ~ 0.35 eV. The rapid proton transport in the superprotonic phase results from the high degree of polyanion rotational disorder. In the case of CsH 2PO 4 the transition occurs at 228 °C and the conductivity rises to ~ 10-2 S/cm at 240 °C, enabling device operation at temperatures between 230 and 260 °C. The physical characteristics of CsH2PO 4 imply a number of realized and potential advantages for their application in fuel cells, electrolyzers, and electrochemical hydrogen pumps relative to polymer, solid oxide, and liquid electrolyte alternatives. We present here an overview of the proton transport characteristics of solid acids and the current status of electrochemical technologies based on these electrolytes.

About Sossina M. Haile

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 PhD degree in materials science and engineering from the Massachusetts Institute of Technology in 1992 and spent two years, 1991-1993, at the Max Planck Institute for Solid State Research in Stuttgart, Germany, first as a Fulbright Fellow then as a Humboldt Fellow.

Haile’s research broadly encompasses materials, especially oxides, for sustainable electrochemical energy technologies. Her work in fuel cell science and technology has pushed the field to new insights and record performance metrics. In parallel, she has created new avenues for harnessing sunlight to meet rising energy demands. Haile has published approximately 200 articles and holds 14 patents on these and other topics.

Amongst her many awards, in 2008 Haile received an American Competitiveness and Innovation 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.” In 2010, she was the recipient of the Chemical Pioneer Award (American Institute of Chemists), in 2012 the International Ceramics Prize (World Academy of Ceramics), and in 2020, the David Turnbull Lectureship (Materials Research Society). She is a fellow of the Materials Research Society, the American Ceramics Society, the African Academy of Sciences, and the Ethiopian Academy of Sciences, and serves on the editorial boards of Materials Horizons, Annual Review of Materials Research and Joule. Her professional service includes past membership on the board of the Materials Research Society, and current membership on the board of Ethiopia Education Initiatives.

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