World's First Battery Fueled By Air

Hugh Pickens writes "The Telegraph reports on the revolutionary 'STAIR' (St Andrews Air) battery could now pave the way for a new generation of electric cars, laptops and mobile phones. The cells are charged in a traditional way but as power is used an open mesh section of battery draws in oxygen from the surrounding air that reacts with a porous carbon component inside the battery, which creates more energy and helps to continually 'charge' the cell as it is being discharged. The battery has a greater storage capacity than other similar-sized cells and can emit power up to 10 times longer. 'The key is to use oxygen in the air as a re-agent, rather than carry the necessary chemicals around inside the battery,' says Professor Peter Bruce of the Chemistry Department at the University of St Andrews. 'Our target is to get a five to ten fold increase in storage capacity, which is beyond the horizon of current lithium batteries.'"

Comments

Re:Any side-effects or drawbacks?

[confused one]

The carbon is only used as a reaction matrix and an electrode. It's a lithium air battery. The oxygen reacts with the lithium during discharge to create lithium oxides. During recharge the oxygen is liberated and returned to the atmosphere.

More informative article

[Tweenk]

There is next to no information in the first article... this one is much more informative:
http://www.theregister.co.uk/2009/05/19/lithium_oxygen_stair_battery/

The concept (taking one of the reagents from air) is not new. There were zinc-air batteries for decades, and they are widely used. They have one of the highest energy densities of all types of commercially available batteries.
http://en.wikipedia.org/wiki/Zinc-air_battery

Seems like four years ago somebody even figured out how to make them electrically rechargeable (before that, the usual method of recharge was to replace the zinc plates and remove oxide waste, which was facilitated by cell design).
http://www.eetimes.com/news/semi/showArticle.jhtml?articleID=164903727

However, if those new batteries use carbon instead of zinc, they might have a higher theoretical upper bound on energy density. It looks like they're using graphite-lithium intercalate for the negative electrode (a standard thing), and the positive electrode is essentially a combined catalyst/adsorbent for Li2O2 which forms during electricity generation.

CnLi ---> Li+ + Cn + e
2Li+ + 2e + O2 --cat.-> Li2O2

Note that the first article is rather bogus: O2 does not "recharge" the battery, it is only a reagent.

I'm not familiar with the cost breakdown for the components of Li-ion batteries, but lithium seems like a major contributor, so this might not be much cheaper than the traditional Li-ion.

Re:Powered by Air?

[morgan_greywolf]

Agreed. It's not even the first battery powered by air in this manner. As Taco ever heard of zinc-air batteries? These are commonly used in, among other things, hearing aids.

Re:Question

[Tweenk]

Addendum: the same amount of oxygen would be liberated when charging. It could be a problem if you decided to charge it in an air-tight box, but under normal conditions it won't be a problem.