A primary focus of hydrogen storage is its application to automotive technology, in particular creating a fuel source that takes up no more space than a standard petrol tank but provides mileage competitive to standard gasoline. It is hoped that the PNNL research will enable the development of solid chemical fuel sources that will release hydrogen as required by the engine.

PNNL researchers Tom Autrey and Anna Gutowska used a nanoscale mesoporous silica material to scaffold ammonia borane, achieving a high rate of hydrogen release at a lower temperature than on the conventional scale, meaning additional energy is not required to maintain the reaction.

The ammonia borane is dissolved in a solvent to make it a nanomaterial before it is added to the scaffold material, capillary action pulling the ammonia borane into the 6.5 nanometre diameter pores as the solvent is removed.

“The compound ammonia borane is known to release hydrogen at temperatures below 80 degrees Celsius but the rate of release is extremely slow. In the nanophase, the hydrogen comes off very fast – approximately 100 times faster compared to conventional bulk ammonia borane,” said Autrey.

Thermodynamic analysis suggests that the process may be reversible, allowing the storage material to regenerate and create a sustainable hydrogen storage compound with a greater lifespan that takes advantage of the size and weight benefits of the nanoscience approach.