Scientists find safer way to store hydrogen
Non-morons defuse potential H-bomb
Australian scientists have come up with a clever way of storing hydrogen that they feel could make it a viable portable fuel source.
Hydrogen is abundant: pass a current through water and you'll make some. Hydrogen-powered fuel cells have therefore been advanced as a potential replacement for the internal combustion engine and even batteries in portable electronics, with Apple holding a patent for Hydrogen batteries.
George W Bush was a fan of the gas: his FreedomCAR program threw a billion dollars at fuel cells among other petroleum-free alternatives. Hydrogen-powered vehicles are also real: an H-Car led the women’s marathon at the Sydney Olympics, way back in 2000, while BMW and Toyota remain keen on Hydrogen as a fuel.
But the fact remains that Hydrogen burns rather well (while it did not cause the Hindenburg's demise its Hydrogen nonetheless burned) and can under some circumstances react nastily with other substances at room temperature. As nobody wants their car to go up in smoke, or for the fuel in its tank to spontaneously become an acid, exploration of fuel cells’ potential has moved slowly as boffins try to figure out the larger problem of just how to build a supply chain around a substance rather more volatile than petroleum.
Enter the Australian team from the University of New South Wales, which has found that compound named sodium borohydride (that’s NaBH4 for all you chemists out there) can absorb lots of hydrogen and then release it under what the researchers describe as “mild pressure conditions” of four mega pascals (4 MPa). That’s rather less than the rating of most scuba diving cylinders and presents a less tricky challenge than storing the gas as .. well ... a gas.
Dr Kondo-Francois Aguey-Zinsou, lead author of a paper on the subject published in ACS Nano, told ABC News NaBH4 acts like a “sponge” for hydrogen, and can soak up so much of the stuff that a conventionally-sized fuel tank stuffed full of the compound would get close to the energy potential of the same volume of petroleum.
But the news isn’t all good: the NaBH4 needs to be nano-engineered and stored in a nickel shell. Even then it only releases some of the stored hydrogen at 50 degrees Celsius and it’s only once the mercury hits 350 that the hydrogen really starts to flow.
The Center for Functional Nanomaterials at UNSW’s School of Chemical Engineering, where the work was conducted, intends to keep tinkering with NaBH4 as it believes there is the potential for “ … major advancements in the design of effective hydrogen storage materials from pristine borohydrides.” ®
Hydrides have *always* been the dark horse in the H2 storage race.
40atm is c 600psi. This is *very* reasonable compared to the 5000psi of normal GH2 tanks and +50c - +350c is also a *lot* easier to handle IRL than the -250c needed for LH2 (unless you are used to fueling launch vehicles).
Let's not forget that the cooling or compressing can use 3x the amount of energy needed to *make* the H2 in the first place.
Bringing the storage temp and pressure more into a range most people are comfortable would make Hydrogen more acceptable but probably cheaper.
Thumbs up for them pursuing a smart rather than simple solution to a very difficult problem.
Re: "can soak up so much of the stuff ..."
i can't see how you can adsorb a material to a higher density than a bulk liquid.
By rearranging things chemically so that the density of hydrogen atoms loosely bound to some carrier compound is greater than the density of hydrogen molecules in liquid hydrogen. It's akin to the old party trick of pouring a pint of water into a pint glass already full of sawdust. It all goes in! (Water packs more tightly around just about anything, than the dynamicall changing open structures in liquid water).
The density of liquid hydrogen is an extraordinarily low 0.07 (water is 1.0) so there's a lot of scope for it to pack down into the interstices of open crystal structures. That's the problem with storing hydrogen at high pressure in metal tanks. It does pack down into the interstices in the metal crystals, and as this happens, the metal becomes progressively embrittled.
(Source for 0.07 http://en.wikipedia.org/wiki/Liquid_hydrogen corroborated elsewhere by Google. That's quite a lot less than 1/4 the density of petrol. More like 1/12 working from memory)
What is the problem?
"once the mercury hits 350 that the hydrogen really starts to flow" I have a little bottle of mercury and I can use it to hit a sign that has the number 350 on it and everything should be good!
Or is this just a really bad example of journalism where they use mercury to mean TEMPERATURE! And if so what units, K, C or F! 350 K is easy to hit (77 C), 350 F is also easy to hit (162 C). 350 C is a bit more difficult.