March 22, 2005
Nanoscale Silica May Be Key To Hydrogen Storage
Will the hydrogen storage problem be solved sooner than expected?
LOS ANGELES – Researchers at the Department of Energy's Pacific Northwest National Laboratory are taking a new approach to "filling up" a fuel cell car with a nanoscale solid, hydrogen storage material. Their discovery could hasten a day when our vehicles will run on hydrogen-powered, environmentally friendly fuel cells instead of gasoline engines.
The challenge, of course, is how to store and carry hydrogen. Whatever the method, it needs to be no heavier and take up no more space than a traditional gas tank but provide enough hydrogen to power the vehicle for 300 miles before refueling.
One approach is to find a solid chemical material that can hold and then release hydrogen as needed. Recently, PNNL researchers Tom Autrey and Anna Gutowska found a way to release hydrogen from a solid compound almost 100 times faster than was previously possible.
These researchers used silica in combination with ammonia borane to accelerate the release of hydrogen from 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.
Hydrogen storage faces a few problems. Getting hydrogen out of a storage medium is just one of them. Another problem is the stage when the hydrogen is stored. Some hydrogen storage methods either require energy be expended continuously to keep hydrogen cold or the storage mechanism is too risky for cars due to accidents and equipment failure. But there is an even earlier step problem that must be solved: How to get the hydrogen into a storage medium quickly, easily, and cheaply? These researchers think they can extend their work on this material to solve the initial storage problem as well.
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.
It is hard to predict when the economy may shift to hydrogen or to batteries for transportation because it is hard to predict when bright scientists and engineers will come up with solutions to the many problems holding back various energy storage approaches.
Promising. There has been, I think, three other potential methods announced this month. Hopefully one will turn out as viable.
There's still the problems of wholesale to retail transport. Hydrogen could be shipped via tanker truck which is not really more dangerouse than petrochemical transport. There would be a public relations problem initially though. Also production onsite by whatever means would work for rural, low volume sales locations.
However progress is good and raises hope, I'd willingly pay more for a non-imported fuel which generated more jobs in the nation.
There's been reports along these lines for several years now but they always fail to mention the most salient fact: cost. Technical elegance is great, but what good is a hydrogen gas tank that costs more than the rest of the car put together.
We have all these fantastic super-engineered materials but most houses are still built out of bricks, wood, and concrete because what counts isn't raw performance but price-for-performance. The materials constantly being promoted for 'home of the future' aren't nanoscale fibers or exotic alloys but hay bales and rammed earth, for goodness sake!
Is there any reason to think that this technological developement can be commercialized into a vehicle that I could buy on a middle class salary any time in the next 20 years?
wow, great article. i love the soluble approach because it seems much more practical than the metal hydride powder because when the little nano-particles coarsen and clump together, the whole thing can be dissolved and re-precipitated. the key question it addresses is how to make huge surface area cheaply and practically.
i do think hydrogen tanker transport is more dangerous than gasoline transport. not to mention the horrible inefficiency of it... are you thinking liquid or gaseous hydrogen? it certainly isn't happening in a steel pressure vessel. maybe an aluminum one, but that's much lower strength/toughness. and considerably more expensive.
i would guess the answer to that is pipelines, like natural gas, or as you alluded to transport electricity then use on-site H production. that utilizes our existing infrastructure.
We certainly need some way to store electricity better. Even a heavy bulky stationary storage system would be great if it was cheap. Then solar cell output could be stored for use when its dark. Of course the need in that case would be greater once photovoltaics become cheaper - and your guess is as good as mine as for when that will happen.
Yes, I think transporting hydrogen long distances is very problematic. Gaseous hydrogen is going to be hard to handle because it can leak out of the smallest of holes.
So I guess I came to wrong website to ask questions about comercial practicability.
Oh well. When the fields dry out at least I can plant the straw for my home-of-the-future.
Jos - no, there's no reason to believe that it'll be a middle class reality in 20 years. all discussions of hydrogen fuel cell cars should be looked at with more like a 50 year timeline, as this is really the most likely solution for what is essentially a re-fillable, portable, environmentally-friendly electric battery. in the meantime the hybrids will improve and develop much of the needed technology.
in 20 years, you could have hydrogen fuel cell electricity generating capacity that is quite real, perhaps even in 10 years, mainly because
1)marginal improvements in efficiency are a big deal for stationary power
2)could be a way to store excess power in the form of chemical energy for re-burning during peak demand
3)you don't need expensive chemical storage methods for safety reasons like cars, instead they could be large, low-pressure aluminum tanks or pipeline systems.
more optimistic forecasts are probably from lay politicians not burdened by reality or scientists angling to get more funding for research on the same.
and good luck on your straw home, hopefully the big-bad wolf won't blow it down
This may help brighten the picture for the nay sayers. http://www.wpherald.com/storyview.php?StoryID=20050502-011752-1585r If these two work out, we are on a economically viable hydrogen production and storage tract. That leaves only the fuel cell membran cost left to beat. Future looks bright. I'll be one of the first to switch over. :)
I agree with Jos Bleau. All of the hydrogen optomists are essentially ignoring the logistics of the matter. You have to ask, is this technology going to be cost competitive with the engine/gas combo in the next 5-8 years? If that time frame sounds short, consider this: Oil was $20/barrel in '02.
Essentially, it doesn't matter if you can build a car that runs on hydrogen if it costs $500,000. It doesn't even matter if you can build 1,000 that cost $100,000. The real question is, can we build 1,000,000 vehicles like this that cost $25,000? And can we find a way to provide adequate access to fuel stations? That's the type of scale that will reduce our oil consumption and generate worldwide interest. Anything else is just academic.
And lets be practical, all hydrogen economy forecasting is a joke. Daimler-Chrysler said it would have 40,000 vehicles on the road by 2004. It's just PR to keep people calm. Peak oil is around the corner, and most of the world is walking around wearing blinders. According to projections, we'll have increased our oil demand by 60% in 2020. From today's prices, does it look like we can handle another 60%? I doubt we can handle another 30%. Why haven't we built any new refineries for 30 years? Because the poor oil lobbyists can't stand up to those big bad greenies, or because they are damn good businessmen who know just what type of refining capacity they need?
Find a nice house with a solar panel on plot of arable land with a close water supply. And buy a gun. I don't think this is a wave we can ride out, so my advice is, learn to swim.