Improved ion mobility is key to new hydrogen storage compoundMay 19, 2008A materials scientist at the National Institute of Standards and Technology (NIST) has deciphered the structure of a new class of materials that can store relatively large quantities of hydrogen within its crystal structure for later release. The new analysis* may point to a practical hydrogen storage material for automobile fuel cells and similar applications. The abundant element hydrogen could play a role in replacing carbon-based fuels for transportation in the future, but researchers first must develop a method to store and release large amounts of the highly flammable, odorless invisible gas economically and safely. There are materials that are known to trap relatively large quantities of hydrogen, at normal pressures, but to date they all require heating to fairly high temperatures to release the hydrogen. Hui Wu, a research associate from the University of Maryland working in a cooperative research program at the NIST Center for Neutron Research, has been investigating a new hydrogen storage compound that mixes lithium amide with lightweight metal hydrides. Lithium amide can hold more than 10 percent of hydrogen by weight, well above the 6 percent target set by the U.S. Department of Energy as a 2010 goal for a hydrogen storage material for transportation. The material absorbs and releases hydrogen reversibly, but both absorbing and releasing the hydrogen requires high temperatures and also produces a toxic byproduct, ammonia. Metal hydrides also store hydrogen, though not as well, but recently it's been shown that a combination of the two not only can store significant quantifies of hydrogen but also can release it at lower temperatures than the lithium amide alone (about 100 degrees Celsius) while generating much less ammonia. To understand how the compound achieves this, Wu used neutron analysis to work out the atomic structure of the material, which she found consists of layers of calcium between which lithium ions travel rapidly. The easy travel allows the material to transfer the hydrogen at lower temperatures. Also the hydrogen ions in the amide and hydride mixture combine easily and release hydrogen at lower temperature without creating much ammonia. "I found that the mobility of small ions in the mixed amide-hydride system greatly improves hydrogen storage properties," Wu explains. "This finding helps us understand how hydrogen travels in and out of these systems and that may lead to a rational development of better materials for hydrogen storage." ### * H. Wu. Structure of ternary imide Li2Ca(NH)2 and hydrogen storage mechanisms in amide-hydride system. Journal of the American Chemical Society ASAP Article, Web release date: April 30, 2008 National Institute of Standards and Technology (NIST) |
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| Related Hydrogen Storage Current Events and Hydrogen Storage News Articles Computer predicts reactions between molecules and surfaces, with 'chemical precision' Good news for heterogeneous catalysis and the hydrogen economy: computers can now be used to make accurate predictions of the reactions of (hydrogen) molecules with surfaces. An international team of researchers, headed by Leiden theoretical chemist Geert-Jan Kroes, published on this subject this week in the journal Science. Hydrogen Storage Gets New Hope A new method for "recycling" hydrogen-containing fuel materials could open the door to economically viable hydrogen-based vehicles. Delaware State U. scientists refine hydrogen fuel-cell vehicle power plants Hydrogen fuel-cell vehicles (FCVs) can be an important part of the solution to America's energy crisis, says Dr. Andrew Goudy of Delaware State University. He is leading a research team striving to solve a key technical FCV puzzle. Researchers demonstrate reversible generation of a high capacity hydrogen storage material Researchers at the U.S. Department of Energy's Savannah River National Laboratory have created a reversible route to generate aluminum hydride, a high capacity hydrogen storage material. Feather fibers fluff up hydrogen storage capacity Scientists in Delaware say they have developed a new hydrogen storage method - carbonized chicken feather fibers - that can hold vast amounts of hydrogen, a promising but difficult to corral fuel source, and do it at a far lower cost than other hydrogen storage systems under consideration. A touch of potassium yields better hydrogen-storage materials An international research team, including Professor Rajeev Ahuja's research group at Uppsala University, has shown that small additions of potassium drastically improve the hydrogen-storage properties of certain types of hydrogen compounds. New storage system design brings hydrogen cars closer to reality Researchers have developed a critical part of a hydrogen storage system for cars that makes it possible to fill up a vehicle's fuel tank within five minutes with enough hydrogen to drive 300 miles. Researchers Create Catalysts for Use in Hydrogen Storage Materials A team of scientists from Virginia Commonwealth University, the University of Uppsala in Sweden, and the Savannah River National Laboratory have identified that carbon nanostructures can be used as catalysts to store and release hydrogen, a finding that may point researchers toward developing the right material for hydrogen storage for use in cars. Revealing new applications for carbon nanomaterials in hydrogen storage An international research team, involving Professor Rajeev Ahuja at Uppsala University and researchers in the USA, set out to understand the mechanism behind the catalytic effects of carbon nanomaterials. Hydrogen tank lighter than battery Dutch-sponsored researcher Robin Gremaud has shown that an alloy of the metals magnesium, titanium and nickel is excellent at absorbing hydrogen. More Hydrogen Storage Current Events and Hydrogen Storage News Articles |
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