H2 storage breakthrough?

[Dr Mordrid]

Finally - a one-pot, efficient means of producing ammonium borane;

Gizmag article....

Pacific Northwest National Labs paper.....

Gizmag;

Hydrogen storage breakthrough - a stable white powder with a higher yield than liquid nitrogen.

June 24, 2008 Hydrogen offers many benefits as a renewable and sustainable fuel of the future as its combustion emits only water. The main problem to now is that it must be stored as a gas, which is potentially dangerous for everyday use, and it can only be stored as a liquid under cryogenic conditions. Now there may be another alternative. Chemists in the US have developed a simple reaction to make ammonia borane (AB) – a powder more hydrogen-dense than even liquid hydrogen. AB is a stable white powder which releases hydrogen gas upon heating. Its use as a hydrogen storage material has been hampered by difficulties in making the powder in reasonable yield, but the new research further increases its promise.

Chemist Tom Autrey and colleagues from Pacific Northwest National Laboratory, US, discovered the “one-pot” method of making AB while studying its decomposition pathways. The group was pleasantly surprised that “under relatively simple reaction conditions the ammonia borane was formed in very high yields.”

The group is researching new designer materials to store hydrogen safely, so that it can be released at will to power a fuel cell. The group is currently looking at scaling up the reaction to an industrial level.

Autrey says the next challenge is to “recycle the solvents to provide the most economical route to synthesise this promising hydrogen storage material.”

Their one-pot synthesis of this promising hydrogen storage material is reported in the first issue of the new Royal Society of Chemistry journal Energy & Environmental Science.

[Claymonkey]

This is extremely promising. The image of filling up your car's 'gas' tank with a sack of flour/sugar is pretty funny though.

[Brian Ellis]

The word "breakthrough" is hardly correct. This substance has been looked at for at least a decade.

It has a lot of ifs and buts attached to it, especially if you think of it as a fuel tank for cars. Where it does have a potential application is as a lightweight power source for combat troops, a small insulated pack of the stuff (the size of a large book but weighing only about 1.5 kg being able to supply H2 on demand to a separate PEM fuel cell of equal size to give typically 50 W for up to 72 h.

One of the downsides is that recharging H2 into the stuff requires a lot of energy, heating to 500°C and this is apart from the energy needed to make the H2 in the first place. Then, the reaction to release the H2 needs heating to 70-100°C initially, rising to 170°C to get the last "drops" out.

The overall well-to-wheels efficiency of a car using this technology would be considerably less than 10%, compared with direct fuel combustion in a conventional car of ~20% and the cost of the H2 "burnt" in the fuel cell would be 3-4 x that of conventional fuel (even at $150/bbl). The carbon emissions would be roughly doubled.

I foresee portable applications becoming probable (there are already AB-powered professional video cameras available), but I don't see it for transport applications before oil reaches $800/bbl and even then ...???

[Fat Tone]

Well that took about 6 hours longer than expected.

[Brian Ellis]

6 hours because I've had a helluva day. My Environment and Energy Forum went down last night and I decided to take the opportunity to upgrade it so I had several hours worth of FTP uploading, during which my ISP suffered a denial of service Finally found one file that had gone corrupt on the server. Now everything is back in order, but it took several hours.

[Dr Mordrid]

I think the breakthrough they're claiming isn't in the material itselfk, which is as Brian stated something they've been looking at for a while, but in the higher efficiency of its production.