A nanotechnology approach to cracking the problem of storing hydrogen for fuel cells is the subject of a research drive by EADS's Innovation Works research arm and the University of Glasgow's chemistry department.
Professor Duncan Gregory hopes to find a new solid-state storage system based on a nanoscale metallic sponge capable of storing a useful quantity of hydrogen and delivering it to a fuel cell at a rate fast enough to power a small aircraft.
Gregory has yet to determine how the mass and energy output of a solid-state tank and fuel cell system will compare with a conventional liquid hydrocarbon fuel and internal combustion engine system or with battery-powered electric systems, but is confident that solid-state storage will prove to be lighter and safer than existing compressed or liquefied hydrogen systems.
Fuel cells theoretically offer much greater energy density than current-technology batteries, but hydrogen storage is problematic. For liquification, the gas must be cooled to -253°C (-423°F) and even the best-insulated storage systems lose 1% a day.
An alternative is compression, but either approach is energy-intensive and demands heavy storage tanks. The resulting energy density is relatively low, with automotive systems having so far proved disappointing when it comes to vehicle range.
If successful a solid-state storage system could transform the prospects for hydrogen as an energy source for aircraft or automobiles. EADS Innovation Works hopes that developing a fuel tank will allow it to fly an unmanned hydrogen-powered aircraft in 2014, with a view to later development of commercial aircraft.
Initially, research will focus on using nanotechnology to alter the structure of the Hydrisafe fuel tank under development in Scotland by Hydrogen Horizons. The tank uses the established and commercially available lanthanum nickel (LaNi5) storage alloy, but Gregory's team will look at alternatives such as magnesium hydride (MgH2), which has been modified at the nanoscale to allow it to receive and release the hydrogen at an even faster rate.
Modifying the construction of the tank may also extend its longevity.
Solid state storage has been considered a hopeful approach for several years. Russia's United Aircraft is also investing heavily in nanotechnology research into compact hydrogen systems.
Source: Flight International
