## UK Researchers Developing Rechargeable Lithium-Air Battery; Up to 10X the Capacity of Current Li-ion Cells

##### 18 May 2009
 Diagram of the STAIR (St Andrews Air) cell. Oxygen drawn from the air reacts within the porous carbon to release the electrical charge in this lithium-air battery. Click to enlarge.

Researchers in the UK are developing a rechargeable lithium-air battery that could deliver a ten-fold increase in energy capacity compared to that of currently available lithium-ion cells. The research work, funded by the Engineering and Physical Sciences Research Council (EPSRC), is being led by researchers at the University of St Andrews with partners at Strathclyde and Newcastle.

Initial results from the project delivered a capacity of 1,000 mAh g-1, while recent work has obtained results of up to 4,000 mAh g-1.

Lithium-air batteries use a catalytic air cathode in combination with an electrolyte and a lithium anode. Oxygen from the air is the active material for the cathode and is reduced at the cathode surface. An issue with Li-air batteries can be the accumulation of solid reaction products on the electrode, which blocks the contact between electrolyte and air.

The four-year EPSRC research project, which reaches its halfway mark in July, is targeting the development of a Li-air cell that is rechargeable and can sustain cycling. The project addresses a number of the materials issues necessary to realize this high energy storage battery based on a non-aqueous O2 electrode. During the project, the team has so far more than tripled the capacity to store charge in the STAIR (St Andrews Air) cell.

The project is focused on understanding more about how the chemical reaction of the battery works and investigating how to improve it. The research team is also working towards making a STAIR cell prototype suited, in the first instance, for small applications, such as mobile phones or MP3 players.

The key is to use oxygen in the air as a re-agent, rather than carry the necessary chemicals around inside the battery. Our target is to get a five to ten fold increase in storage capacity, which is beyond the horizon of current lithium batteries. Our results so far are very encouraging and have far exceeded our expectations.

—Professor Peter Bruce of the Chemistry Department at the University of St Andrews, principal investigator

Bruce estimates that it will be at least five years before the STAIR cell is commercially available.

The four-year research project “An O2 Electrode for a Rechargeable Lithium Battery” began on 1 July 2007 and is scheduled to end on 30 June 2011. It has received EPSRC funding of £1,579,137 (US$2.4 million). Earlier this year, researchers at Japans’s AIST (Advanced Industrial Science and Technology) also reported progress on the development of a very high capacity Lithium-air battery. ### Comments One more superior capacity Li-something chemistry, 5 years from commercial product, same as other promising technologies, so just wait and see... I would think this would be the kind of chemisty for military applications, where they will blow off price and lifetime, in favor of really high performance short term. What does it say the this little university with a couple million dollars may deliver an answer that billions of dollars of consortiums haven't been able to deliver? Does that suggest the STAIR cell is unlikely to overcome it's short number of charge cycles, or does it suggest that we should place a lot more$2 million bets on high-risk, high-return technologies?

If there really is the likelihood of getting "results of up to 4,000 mAh g-1", then it might take less than five years. Some serious funding will find it's way here and speed things up.

Lithium-air, lithium-sulfur, nano-lithium, etc. The future looks bright but why wait for the batteries to get here? When Ford came out with the model T did America wait for the Fusion?

Will that technology work with the highly polluted air we have in many cities or will it require purer oxygen for high sustained performance?

It would be amazing (almost a giant leap forward for PHEVs, BEVs and plain e-storage) to have a similar affordable storage unit (800 Wh/Kg) in production within 5 to 6 years.

It seems that with all the development going on, much higher performance e-storage units will be around by 2015 or shortly thereafter.

It may be too early to scrap our gas guzzlers but the time to start planning how and when to dispose of them may come soon.

Unfortunetly like some fuel cell projects and some other .... to good to be true crap this is likely just a research money grab and cant actualy create a useful end result.

Many supposedly great lithium battery chems dont work simply because they are so reactive they kill the battery in no time at all. Even many of the not so UBER chems still have to sacrifice almost all of the lifespan to just get somewhat better energy capacity.

As I understand it the key to longevity is keeping everything but oxygen out of the battery.

And the biggest drawback is that these batteries store a tremendous amount of energy but are reluctant to release it rapidly; no high amperage. I would infer that also means recharging will be slow.

Not for low temperatures either.

Of course voltage can be boosted with multiple cells so that current per cell is low but that is hardly free.

Is that about right?

I hope the lithium-air concept succeeds.

The matter of energy density (i.e. watt-hours per Kg of weight, or per unit volume) versus power density (i.e. watts per Kg or per cubic meter) has always been an issue in battery engineering.

If the Li-air battery has a low power density, perhaps one could use ultracapacitors in addition to said battery. Here, the high power density (and low energy density) of the former offsets the low power density (but high energy density) of the latter.

It would be nice if someone could solve the technical problems of engineering a rechargeable aluminum-air battery. Such batteries have a beautiful energy density, but right now are not rechargable.

Until they give solid lifespan numbers ill just slot this right there with eestor.

wintermane:

Don't you think that it may be the ideal EEStor companion?

Technological progress is incremental. Breakthroughs however cannot be predicted. Here we have a battery chemistry that has a high payoff if it can be developed.

Great news.

Polyplus reckon the lithium-air couple has a theoretical energy density of 11,600 Wh/kg, of which probably 3,000 Wh/kg can be easily realised. Compare that to the ~100 Wh/kg used in GM's Volt batteries.

Should by-gone GM and Chrysler have gone Chapter 7 some 6+ months ago and the same $25+ used to design and mass produce very high performace batteries? It's no use to try to extend the life of an older technology we can't afford to feed with liquid fuel we do not have. Those$\$B would have been better invested into future technology vehicles and storage units.

This is old news; Li-air batteries have a 25+ yr history and still a lot of problems to overcome (see the USPTO site and these two papers by K. M. Abraham:

“ Non-aqueous Lithium-Air Batteries with an Advanced Cathode Structure”, in Proceedings of 41th Power Sources Conference, Philadelphia, PA, 2004

“Cathode Optimization of Lithium Air Batteries”, Fall Meeting of The Electrochemical Society, Los Angeles, CA, September 2005. Abstract No. 823.)

Interestingly, the original paper by P. Bruce was published 3 years ago in J. Am. Chem. Soc. 128, 1390 (2006); perhaps something 'nano' was added to spice it up? :-)

--lzp

Interesting comments. The difference here is that these are Scottish universities and are well known to produce results which others do not. Marketable batteries will come in much sooner than 5 years...the Scots will not predict any differently than other researchers, BUT, invariably provide pleasant surprises at lower costs as time goes on.

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