Jeff Bunn-Task 3 Team Member

Primary Research Advisor: Prof. Dayakar Penumadu
Primary Research Task: Characterizing Membranes in the Fuel Cell Using Neutron Tomography

I trained as a Civil Engineer and received my BS in Engineering with a civil concentration from the University of Tennessee - Martin. During an internship at Oak Ridge National Laboratories (ORNL) my junior year, I became interested in material science, specifically neutron scattering. My research was concentrated in residual strain determination using neutron diffraction. After meeting a civil engineering professor at UT, I decided to continue this interest in graduate school. I feel great pride knowing that my graduate school work could have a real impact on the world around me. I am uniquely positioned to study fuel cells on an in-situ basis using my background in neutron science. Also, my experience in Civil Engineering has led me to be interested in many other “green” materials such as pervious concrete for parking lots and photovoltaic cells for low energy consumption homes. My Task 2 research, characterization of fuel cells, involves testing different GDL’s and PEM’s as well as in-situ studies of working fuel cells.

I enjoy many outdoor activities: hiking, sailing, and playing ultimate and disc golf. My favorite trail in the Great Smoky Mountains is the Alum Cave Bluff Trail. I love music in most all forms and grew up playing percussion in a marching band. I am a member of Phi Mu Alpha Sinfonia Fraternity, a social music fraternity. My favorite band is 311. I also like video games and try to play my Xbox 360 whenever I get the time to do so.

Research
The shortcomings of current fuel cell technology are numerous. Low temperature and high humidity fuel cells (< 90° C) as well as high temperature and low humidity fuel cells (>100° C) both suffer from low power generation. The current PEM’s (Polymer Electrolyte Membranes) are fuel cells that are made from an acid polymer such as nafion. The dependency of proton conductivity on polymer morphology is not well understood. Also, the oxidation between hydrogen and a metal catalyst (usually Pt or PT/Ru) to create a current of electrons tends to lead to problems with H₂O production. Fuel cells operate on the edge of efficiency. Too little water and they do not conduct enough electrons; too much water and the reaction is slowed. Therefore, water management is a large issue. Neutron imaging, in the form of both radiographies and tomographies, will be utilized to characterize the morphology of these PEMs. Furthermore, neutron techniques can take advantage of the effect that neutrons will be greatly attenuated by H₂O and not by the surrounding materials. This can help spatially quantify water content and pair this analysis with current production of the fuel cell.

E-mail: Jeff Bunn

Additional information on each of the three research areas can be found in the links below.

• Task 1: Production of hydrogen through biological pathways
• Task 2: Discovery of nanoporous materials for hydrogen storage
• Task 3: Identifying structure/property relationships in hydrogen-based fuel cells