ChBE Seminar Series: Daniel Hussey
Tuesday, November 3, 2009
11:00 a.m.-12:15 a.m.
Room 2110, Chemical and Nuclear Engineering Bldg.
Professor Chunsheng Wang
Neutron Imaging and the Study of Electrochemical Energy Sources
Presented by Daniel Hussey
National Institute of Standards & Technology (NIST)
In situ observation and measurement of changes in the electrolyte during operation is a challenge in electrochemical energy sources. In proton exchange membrane fuel cells, the membrane water content dictates proton conductivity and is affected by numerous operating conditions including temperature, current draw, gas flow, and inlet gas humidity. In alkaline primary cells, the swelling of the anode as Zn oxidizes reduces the volume fraction available to the electrolyte and accelerates the end of life. The structure of typical electrochemical energy sources, a hydrogenous electrolyte surrounded by a metallic matrix, poses measurement hurdles to typical imaging techniques, as x-ray imaging has poor contrast for hydrogenous material compared to metals and magnetic resonance imaging most overcome the self-shielding of the metallic electrodes. Neutron imaging by contrast has very high sensitivity to hydrogen, while easily penetrating many common metals, making the technique an ideal electrochemical microscope. The talk will give an overview of neutron imaging, focusing on the use of the technique to study fuel cells and batteries.