August 2007

New Hydrogen Research Contract Develops Process for Screening Storage Materials

“If the idea of a ‘hydrogen economy’ that everyone is talking about these days is ever to become a reality, then one of the major technology issues yet to be solved is the area of hydrogen storage.  If hydrogen can be stored safely and efficiently, it will open up many potential applications for its use.  There are many possible candidate materials that can store hydrogen out there, and finding the right one is like looking for a needle in a hay stack! We’ve got a new idea that will speed up the screening of storage materials and help us move toward the hydrogen economy goal much quicker.”

With those words, FSEC’s Hydrogen Research Director Ali Raissi described the goal of the center’s new contract to develop a novel high throughput material screening apparatus for a wide range of hydrogen sorbing compounds.  Funded by the Navy and Defense Logistics Agency, the $375,000 contract will enable FSEC researchers to demonstrate the proof-of-concept rapid materials characterization for identifying superior hydrogen storage compounds -- speeding the pace of the discovery by several orders of magnitude.

Hydrogen storage compounds are special materials that can reversibly absorb hydrogen at preferably low, near-ambient conditions. By varying the pressure and/or temperature of these materials it is possible to release the hydrogen and use it to generate power in fuel cells and other devices.

“What this new process simply means,” Raissi explained, “is that we can take the unique hydrogen sensing tapes that we developed as part of our ongoing NASA-funded activity and incorporate them into a specially designed apparatus that allows discovery of new hydrogen storage materials much quicker than ever before.  Storage is one of the major challenges facing realization of a hydrogen economy, and this new project will let us develop a unique process for rapidly screening candidates for hydrogen uptake, cutting the time now required for screening for hydrogen storage materials from hours to literally just seconds.”

FSEC researchers have been working on hydrogen storage compounds for a number of years, looking at their properties such as capacity, temperature at which hydrogen will be released and so forth.  Since there are a large number of possible material combinations that can store hydrogen, it is important to be able to screen and test these materials quickly.  Thanks to the support of the Navy, which is very interested in the use of hydrogen, the project will develop a new device for testing as many as 100 potential hydrogen storage materials or more in just a few minutes. 

Raissi explained that the current procedure is to take the candidate materials -- compounds like metal hydrides and others -- and examine them one at a time, a process that is very time-consuming. 

An important part of the new contract will be for FSEC to be able to measure the amount of hydrogen released for up to 100 solid adsorbents simultaneously at a wide range of temperatures and pressures.  The work will involve close collaboration with colleagues at the Naval Research Lab to identify and use appropriate hydrogen sorption materials for the calibration and performance verification of the FSEC-developed rapid screening apparatus.

Photo of chemochromic film that was exposed to hydrogen.
A 25-mil thick section of FSEC-developed
chemochromic film after exposure to various
quantities of hydrogen gas.

FSEC researchers have already developed a sensing membrane that contains special hydrogen sensing pigments that change color when exposed to hydrogen gas.  “What will make this new approach work,” Ali explained, “is that we will be able to simply visually inspect the chemochromic membrane after each dehydriding test run.  The changes in the color of the membrane will give us a direct reading on the amount of hydrogen release from the samples.”  

It is this ability of the naked eye to view the materials and quickly determine their hydriding/dehydriding properties that will spur the research process and allow a large number of hydrogen storage materials to be screened within minutes.  The current screening techniques are hampered by the time-consuming need for sequential rather than parallel measurements.  Speeding up the screening process is one more accomplishment in addressing the hydrogen storage challenge.