24 January 2012
(Odometer: 8,905 miles)
COLLEGE PARK, MD.–Fuel cells are remarkably efficient ways to store and discharge energy, but the word "hydrogen" tends to freak people out, and the hydrogen filling infrastructure just doesn't exist right now.
These PEM (proton exchange membrane) cells are currently on the shelf, as it were, as research and development has shifted toward batteries of all kinds, particularly to power electric vehicles.
"These things tend to cycle as far as what's popular and not popular," says materials science Prof. Erich Wachsman with the University of Maryland's Energy Research Center.
Batteries were big in the Clinton Administration and then faded from the funding picture to be replaced by funding for fuel cells for a time. Funding has now, under Steven Chu at the Department of Energy, shifted back to battery technology because there just isn't much of an infrastructure for hydrogen fuel cells.
There are two approaches to fuel cells–PEM and solid oxide fuel cell (SOFC). SOFC has incredible energy density and can oxidize almost any fuel source (e.g., diesel, gasoline, natural gas). Its Achilles heel is that it operates at high temperatures–around 800 degrees C. PEM cells operate around 80 degrees C, and that's the reason they're discussed in automotive applications.
But Wachsman and his colleague Kang Taek Lee claim an SOFC breakthrough. They've created a 10 x 10 cm cell that operates at 650 degrees C with three times the power density of an internal combustion engine. Each cell can generate up to 200W, he says.
In a paper published in Science around the time of our visit, Wachsman and his colleagues chart a path to push the operating temperature down to 350 degrees C using different electrolytes.
He talked about the technology in his offices here: