SGER: Solid Acid Fuel Cells for the New Era of Sustainable Energy

California Institute Of Technology, Pasadena CA

Investigators

Abstract

The aim of this SGER research project is to develop solid acid based fuel cells that take advantage of the many benefits inherently offered by anhydrous, warm-temperature, proton conducting electrolytes. Composite electrolytes comprised of phosphate solid acids and nanoparticulate oxides will be studied. Such materials are known to exhibit high proton conductivity at temperatures lower than what is normally required for the pristine solid acid, and are likely to display mechanical properties sufficient for thin membrane fabrication. The specific combination of materials to selected for investigation is a cesium / rubidium phosphate solid acid and a proton conducting oxide, yttrium doped barium zirconate. This class of materials is anticipated to have excellent chemical stability in the fuel cell environment. Key scientific questions center on interfacial phenomenon that are believed to be responsible for the enhancement of the conductivity for composite materials over pristine solid acids. To address these questions, samples will be examined by in situ high temperature X-ray diffraction and solid state NMR spectroscopy. In parallel, complete fuel cell characterization of membrane-electrode-assemblies will be performed, and the suitability of these materials for applications assessed. With a fundamental understanding of the mechanisms by which composite materials can give rise to high conductivity, in combination with fuel cell performance evaluation, it will be possible to engineer composite architectures which fully exploit the potential for excellent electrical and mechanical properties. %%% The proposed studies will help to clarify the phenomenon of enhanced proton conductivity in composite materials, while simultaneously providing an assessment of the suitability of such materials to fuel cell applications for sustainable energy production. ***