Tuesday, April 1, 2008 - 4:50 PM

Accelerating discovery of high capacity metal hydrides for reversible hydrogen storage using first-principles calculations

David Sholl, Georgia Institute of Technology and J. Karl Johnson, University of Pittsburgh.

One of several daunting challenges associated with hydrogen storage for vehicular applications is the necessity of releasing hydrogen at temperatures readily accessible in fuel cell vehicles. Simple metal hydride can reversibly store large amounts of hydrogen, but typically require very high temperatures to release hydrogen. Physical mixtures of metal hydrides can in some cases have much more favorable reaction thermodynamics than individual hydrides. An enormous number of different mixtures can be contemplated, making systematic screening of these mixtures via direct experiments difficult. We have used rigorous thermodynamics calculations based on first-principles calculations to aid this process. Our computational screening examined over 16 million distinct mixtures, spanning all possible compositions of up to four elements from Al, B, C, Ca, K, Li, Mg, N, Na, Sc, Si, Ti, V in combination with H. Our calculations include all of the ~200 solid crystal structures containing these elements that are currently known. This process identified a large number of reactions that are worth investigating experimentally. In addition to these extensive calculations with bulk stoichiometric materials, we will discuss the use of doping and nanosizing as possible avenues for tuning the reaction thermodynamics of metal hydrides.

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Back to The NHA Annual Hydrogen Conference 2008 (March 31-April 4 2008)