Maybe somebody can explain what’s actually going on here. MIT has a press release out, it crows about the discovery of a catalyst for splitting water (the pod cast there is good) into it’s constituent hydrogen and oxygen. Now I thought that was pretty simple stuff. What’s the hard part?
My model of using hydrogen as an energy storage system was that it became inconvenient in other parts of the system. Hydrogen is a pain to store; transport, etc. The conversion of hydrogen back to energy required over engineered devices; like fuel cells. I’d presumed that making hydrogen wasn’t a problem.
In any case they formed a thin film of cobalt and phosphate on a conductive glass. When they slip the water, using electricity, they get oxygen. I gather that what’s good is that they get the oxygen directly and not thru some inconvient intermediary? Apparently their is a second step that helps to assure they get the hydrogen more directly as well, and I’m not following that either. This second step while straight forward typically is done using platinum as a catalyst; so there is some separate story about how to work around that cost – but that’s not part of this invention.
Apparently it’s very nice that this all happens at room temperature and neutral PH. I guess that’s good, presuming that the existing efficient processes are far from that.
There is apparently a subplot about how the water isn’t pure; but has a dose of phospate in it so the thinfilm is self repairing.
I guess these are my questions. First how much does this simplify existing practice. Second is this actually significanlty more efficent than existing practice. And finally, and I think this is outside the scope of the press release, what is the round trip efficency and complexity of an energy storage scheme based on this?
Update: This posting over at The Oil Drum is quite snarky and dismissive of this “breakthru.” It is a refresing counter point to the ripple of republished MIT PR. Presuming it is correct then what’s different is that existing high efficency electrolisis schemes are more complex than this. How much that effects the capital costs isn’t clear to me, but not much looks likely.
Update: This video is pretty nice and reasonably clear.
I lik Write on!e subplots.
Ah, the keys jumped around on that one, sorry. It said “I like subplots. Write on!”
My understanding affter digging into the chemistry of electrolysis of water is, if you do things the naive way, you are getting mostly H2 plus OH complexed with the metal in whatever salt yer using to make the water more conductive.
This causes two obvius problems – need for external oxygen for the reforming step and the water in the lysis cell ends up very basic.
This disovery keeps the cycle closed and neutral, and this should make it simpler to build closed loop storage devices, AKA batteries with one hopes highenergy density.
A bit more info here: http://blogs.nature.com/thescepticalchymist/2008/08/acs_philadelphia_2008_big_talk.html
I am sure there’s something to it; I certainly would love to see some improvements in battery technology. But we heard a lot of claims about new batteries at iRobot. and none of them lived up to the claims of their inventors. So I have a bit of a jaundiced eye.
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