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Sustainable energy has emerged as the most pressing challenge facing humanity in the 21st century. Fuel cells, because of their high efficiencies and benign emissions, will likely play an important role in a sustainable energy future. In this work we hope to leverage new materials discovery against tailored architectures in order to obtain unprecented fuel cell power outputs. Funding for this work is provided by the National Science Foundation (DMR-0840365 and DMR-0906543).
Solid acids are a fascinating class of materials built upon hydrogen
bonded oxyanion groups. In contrast to polymeric proton conductors,
these compounds conduct protons without the assistance of mobile water
molecules, opening new technological possibilities and scientific
avenues. Our success in fabricating and demonstrating fuel cells based
on these electrolytes has led to the spin-off company, Superprotonic,
Inc. The work is supported by the National Science Foundation (DMR-0906543).
Several oxides of the perovskite structure, notably BaCeO3,
BaZrO3, SrCeO3 etc., can, after appropriate doping so as to contain oxygen vacancies,
adsorb significant quantities of water into their bulk structures.
The protons associated with the incorporated water are present in
the form of hydroxyl groups and can easily migrate from one oxygen
ion to the next. This easy migration results in a high conductivity
and materials that are useful for a range of devices, from fuel cells
to hydrolysis cells to hydrogen separation membranes. This work is supported by the Gordon Moore Foundation, through the Caltech Center for Sustainable Energy Research.
Oxide Fuel Cells
oxide fuel cells (SOFCs) operate at high temperatures, and, as a consequence,
they can utilize hydrocarbon fuels, they provide for efficient catalysis,
and they exhaust 'high quality' waste heat that can be used for additional
power generation. High temperature operation, however, has generally
been responsible for the high cost of SOFCs and for their undesirability
for portable applications. Our efforts in solid oxide fuel cells span
a number of activities. These include the use of ceria as an electrolyte
for reduced temperature operation, the incorporation of ceria in fuel
cell anodes for enhanced electrooxidation activity for complex hydrocarbon
fuels, the development of alternative perovskite cathodes for high
activity oxygen electroreduction, and the operation of fuel cells
in so-called single chamber mode for portable power. This work is funded, in part, by the Global Climate and Energy Program of Stanford University, supported by a consortium of industrial partners, and formerly supported by the Office of Naval Research, through the MURI program. Additional supported is provided by the National Science Foundation (DMR-0840365).
- Solar-Driven Thermochemical Fuel Production
People and Agencies
Variable valence oxides have the important characteristic that at high temperatures, they release oxygen, due to thermodynamic driving force, whereas thermodynamics drives oxygen reabsorbtion at lower temperatures. At the lower temperature, if gases such as water or carbon dioxide are used to reoxidize the material, the reaction generates a reduced fuel such as hydrogen or carbon dioxide as the reaction product. Such thermochemical production, when driven by solar thermal heating, can be used for solar fuel generation. In this work we develop new materials with desirable thermodynamic and kinetic properties for thermochemical solar fuel synthesis. Our initial studies have focused on doped ceria and the results suggest that solar to fuel conversion efficiencies of ~20% can be achieved even in the absence of heat recovery and that fuels ranging from hydrogn and carbon dioxide to syngas and methane can be produced with extremely rapid kinetics. This work is supported by the National Science Foundation (CBET-0829114) and by eSolar.
positions are currently open.
SURF projects for 2014:
- Chemical synthesis of oxide ceramics as candidate cathodes in solid oxide fuel cells.
- Sputtered nanoparticle metals as catalysts for fuel electrooxidation on ceria-based anodes.
- Chemical synthesis of oxide ceramics as candidate materials for solar-drive thermochemical fuel production.
- Chemical synthesis and conductivity measurement of proton conducting oxide ceramics.
- Thermodynamic Assessment of candidate oxides for solar-driven thermochemical fuel production.
- Automation of data analysis for thermochemical fuel production.
Junior or sophomore Caltech students with prior research experience preferred, and, in some cases, only Caltech students will be considered. See individual project descriptions (some still in preparation) for course requirements, recommended prior experience and additional resources.
In addition to applying through the SURF program, interested candidates should
send a resume, transcript and at least one letter of recommendation to Prof.
Sossina Haile and the direct laboratory mentor specified in the project title before requesting further information. Please do not rely on the SURF office to forward this information.