Since the 1970s, hydrogen has been touted as a promising alternative to fossil fuels due to its clean combustion – unlike hydrocarbon-based fuels, hydrogen’s only combustion by-product is water. Compared to gasoline, hydrogen is lightweight, can provide a higher energy density and is readily available. But to replace gasoline as a fuel, hydrogen must be safely and densely stored, yet easily accessed. Limited by materials unable to leap these conflicting hurdles, hydrogen storage technology has lagged behind other clean energy candidates.
In recent years, researchers have attempted to tackle both issues by locking hydrogen into solids and packing larger quantities into smaller volumes with low reactivity – a necessity in keeping this volatile gas stable. However, most of these solids can only absorb a small amount of hydrogen and require extreme heating or cooling to boost their overall energy efficiency.
Now, scientists with the U.S. Department of Energy Lawrence Berkeley National Laboratory have designed a new composite material for hydrogen storage consisting of nanoparticles of magnesium metal sprinkled through a matrix of polymethyl methacrylate, a polymer related to Plexiglas. This pliable nanocomposite rapidly absorbs and releases hydrogen at modest temperatures without oxidizing the metal after cycling – a major breakthrough in materials design for hydrogen storage, batteries and fuel cells.
“This work showcases our ability to design composite nanoscale materials that overcome fundamental thermodynamic and kinetic barriers to realize a materials combination that has been very elusive historically,” says Jeff Urban, Deputy Director of the Inorganic Nanostructures Facility at the Molecular Foundry, a DOE Office of Science nanoscience center and national user facility located at Berkeley Lab. “Moreover, we are able to productively leverage the unique properties of both the polymer and nanoparticle in this new composite material, which may have broad applicability to related problems in other areas of energy research.”