October 4, 2011 — TU Delft and VU University Amsterdam researchers have demonstrated that hydrogen gas stored in a metal hydride is released faster when the metal alloy nanoparticle is smaller. The research, focused on fuel cells, is aimed at reducing the energy required for hydrogen storage.
Today, hydrogen gas is stored at 700 bar pressure in a vehicle’s fuel tank. Tanks are filled by high-pressure pumps that consume a lot of energy. Magnesium and like metals absorb hydrogen in high densities without high pressure. However, hydrogen release is difficult and slow. The research shows that magnesium nanoparticles fixed in a matrix will release hydrogen faster. The matrix prevents the nanoparticles from aggregating and matrix design helps control the hydrogen desorption pressure.
The interaction between nanoparticles and matrix increases hydrogen release speed, said Bernard Dam, Professor of Materials for Energy Conversion and Storage. The researchers demonstrated, on models comprising thin layers of magnesium and titanium, that hydrogen release increased as thinner layers were used.
The Dutch Minister of Infrastructure and the Environment, Ms Schultz van Haegen, plans to earmark EUR5 million to stimulate hydrogen transport systems in the Netherlands. German car manufacturer Daimler is also planning to build 20 hydrogen fuelling stations along Germany’s motorways. Better hydrogen fuel storage will encourage large-scale hydrogen fuel cell adoption, believe the Dutch researchers. It could also enable flex-fuel electric vehicles (EV) that travel short distances on batteries and switch to hydrogen for longer trips.
The researchers publish their findings in the October issue of the scientific journal Advanced Energy Materials. Access "Interface Energy Controlled Thermodynamics of Nanoscale Metal Hydrides" here: http://onlinelibrary.wiley.com/doi/10.1002/aenm.201100316/abstract
The research was funded by the ACTS Sustainable Hydrogen Program of the Netherlands Organisation for Scientific Research.
Learn more about TU Delft at http://home.tudelft.nl/en/.