They will present their findings at the American Physical Society Meeting in Los Angeles on March 21, as part of The Grand Challenge of Hydrogen Storage symposium.
“The compound ammonia borane is known to release hydrogen at temperatures below 80 degrees Celsius, but the rate of release is extremely slow,” said Autrey. “In the nanophase, the hydrogen comes off very fast – approximately 100 times faster compared to conventional bulk ammonia borane.”
The PNNL team used a nanoscale mesoporous silica material as scaffolding for ammonia borane to achieve a high rate of hydrogen release at a lower temperature than is found at the conventional scale. A lower temperature reaction, 80 degrees Celsius (170 degrees Fahrenheit), or below, is important because additional energy is not required to maintain the reaction.
To transform the ammonia borane to a nanomaterial, scientists dissolve the solid compound in a solvent and then add the solution to the mesoporous support material.
Capillary action of the porous material pulls the ammonia borane into the pores of the support. When the solvent is removed, nanosized pores filled with ammonia borane are left. Each pore is about 6.5 nanometers in diameter.
The nanoscience approach to using ammonia borane as a storage material exceeds DOE’s weight and volume storage goals for 2010. As a bonus, it also avoids the volatile chemicals produced at the bulk scale.
“We found no detectable borazine, which is harmful to fuel cells, produced by the reaction in the mesoporous materials,” said Autrey.
Based on computational thermodynamic analysis, researchers believe the process may eventually be designed to be reversible, which would allow the storage material to be regenerated and provide a sustainable hydrogen storage compound with a longer lifetime. A patent is pending on this process for hydrogen storage.
Business or public inquiries on this or other PNNL innovations can be directed to 1-888-375-PNNL or inquiry@pnl.gov.
PNNL (www.pnl.gov) is a DOE Office of Science laboratory that solves complex problems in energy, national security, the environment and life sciences by advancing the understanding of physics, chemistry, biology and computation. PNNL employs 4,000, has a $650 million annual budget, and has been managed by Ohio-based Battelle since the lab’s inception in 1965.
PNNL press release.
I’m actually in LA right now, attending the APS March meeting (currently listening to some talks on complex networks – the internet, and economic networks, and more…)
Anyway, I attended part of the “hydrogen grand challenge” session yesterday, but I missed this particular talk. None of the ones I saw seemed very spectacular – and nobody seemed to see any of this stuff coming any time soon. Scientists love “grand challenge” projects, but the title tells you something: there’s way more scientific work needed before it becomes practical. Nowhere in the meeting, unfortunately, is there any discussion of solar photovoltaics for example, as there seems to be essentially no funding for research (or at least basic physics research) on those systems.
Energy storage is certainly an important problem, but hydrogen is probably not the best solution. Hydrocarbons (like gasoline) store hydrogen in liquid form about as well as anything else!
Hydrogen is an energy carrier, not an energy source. In order to create hydrogen fuel, conventional energy sources must be utilized. The development of hydrogen technologies does nothing to address the uncerlying energy crisis.
you can create hydrogen using renewable sources. the idea is simple, transition away from using fossel fuels directly, build a hydrogen infrastructure, then gradually faze in solar/wind/geothermal to replace the fossel fuels.
Not sure what rickyjames’ point is about 10000 psi, the pressure rating of the tanks a presumably valued GM executive (Larry Burns?) was photographed standing next to. They would have to be at full pressure for the picture to be meaningful; any other setup would be like having the governor of California pretend to refuel a hydrogen Hummer with a hose that was connected, not to an actual hydrogen pump, but to another mockup.
At 10000 psi and 25 Celsius hydrogen’s energy-specific volume is 980 litres per megawatt-hour, nine times that of gasoline. At 5000 psi, 1382 L/MWh, 12.75 times gasoline’s volume; not counting, in either case, highly stressed tank wall volume. So yes, “something else is needed”, for sure.
But plausible candidates aren’t hard to find. For instance, the energy-specific volume of aluminum is 46 L/MWh, and the oxide produced in the process of getting that megawatt-hour out, and in a zero-local-emission system retained, has a single-crystal volume of 58 L. For poorly consolidated powder, 150 L should be plenty, and we have a system volume ~200 L/MWh. Gauge pressure, if there were a gauge — zero.
True, this is still twice gasoline’s energy-specific volume, but there are litres and litres. Aluminum and its oxide can both go in litres on board a vehicle that would not be good for gasoline.
— Graham Cowan, former hydrogen fan
boron: how individual mobility gains nuclear cachet
Safety, I presume.
Safety, indeed. Take a look at this report about a scuba tank that exploded.
“The explosion was roughly equivalent to several sticks of dynamite. According to one scuba tank inspection expert, “The explosive potential in a fully charged 80cf aluminum SCUBA cylinder is approximately 1,300,000 foot pounds — enough to lift a typical fire department hook-and-ladder truck over 60 feet in the air!”.
If this is the situation with a “little” 3000 PSI scuba tank full of chemically inert air that’s rated to 5000 PSI before it explodes, YOU WOULD HAVE TO BE NUTS TO GO DOWN A HIGHWAY AT 60 MPH SITTING ON TOP OF THREE “BIG” 10,000 PSI TANKS FULL OF EXPLOSIVE GAS.