Sossina Haile

Walter P. Murphy Professor of Materials Science and Engineering
Professor of Applied Physics, Northwestern University


Sossina Haile received her B.S and Ph.D (1992) from the Massachusetts Institute of Technology, and M.S. from the University of California, Berkeley. Before joining the Caltech faculty in 1996, Haile spent three years as an assistant professor at the University of Washington, Seattle. Haile has received the NSF National Young Investigator Award (1994-99), Humboldt Fellowship (1992-93), Fulbright Fellowship (1991-92), and AT&T Cooperative Research Fellowship (1986-92). The Humboldt and Fulbright fellowships supported her research at the Max Planck Institut für Festkörperforschung [Institute for Solid State Research], Stuttgart, Germany (1991-1993). She is the recipient of the 2001 J.B. Wagner Award of the High Temperature Materials Division of the Electrochemical Society, the 2000 Coble Award from the American Ceramics Society and the 1997 TMS Robert Lansing Hardy Award.

Sossina Haile's research broadly encompasses solid state ionic materials and devices, with particular focus on energy technologies. She has established a new class of fuel cells based on solid acid electrolytes and demonstrated record power densities for solid oxide fuel cells. Her more recent work on water and carbon dioxide dissociation for solar-fuel generation by thermochemical processes has created new avenues for harnessing sunlight to meet energy demands.

Specific materials under investigation in Dr. Haile's group include proton-conducting solid acid compounds, mixed oxygen- and electron-conducting fluorites and perovskites, and proton-conducting perovskites. Characterization tools range from A.C. impedance spectroscopy in a variety of configurations to x-ray and neutron scattering and thermal analysis. In many cases, specialized in-house tools are constructed allowing acquisition of data otherwise inaccessible using commercial instrumentation. Using these methods, her group has shown, for example, that defect trapping plays a significant role in limiting the magnitude of proton conductivity in yttrium-doped barium zirconate, one of the most promising electrolytes for reduced-temperature solid-oxide fuel cells.Visit the Haile group research page to learn more about these activities.Ph.D. Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA

Research Interests

Overall research goal is to elucidate the relationship between structure and electrical behavior in electrochemically active solids, as a key step towards designing materials with exceptional properties and applicability in sustainable energy technologies.


  • Ph.D. Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA
  • M.S. Materials Science and Engineering, University of California - Berkeley, Berkeley, CA
  • B.S. Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA


  • W Jung, K. L. Gu, Y. Choi and S. M. Haile, “Robust nanostructures with exceptionally high electrochemical reaction activity for high temperature fuel cell electrodes.”  Energy Env. Sci. 7, 1685-1692 (2014).
  • Y. Yamazaki, F. Blanc, Y. Okuyama, L. Buannic, J. C. Lucio-Vega, C. P. Grey, and S. M. Haile, “Evidence of proton trapping and its implications in yttrium-doped barium zirconate,” Nature Materials 12, 647-651 (2013).
  • W. C. Chueh and S. M. Haile, “Electrochemistry of Mixed Oxygen Ion and Electron Conducting Electrodes in Solid Oxide Fuel Cells and Electrolyzers,” Annu. Rev. Chem. Biomol. Eng. 3, 313-41 (2012).
Sossina Haile