Green Car Congress  
Go to GCC Discussions forum About GCC Contact  RSS Subscribe Twitter headlines

« Daikin to begin producing Li-ion electrolytes | Main | China’s CNOOC to acquire Canada-based Nexen for $15.1B; offshore oil and gas, oil sands, and shale gas »

Print this post

Univ. of St. Andrews researchers show reversible, higher-rate non-aqueous Li-air battery using gold cathode and DMSO electrolyte

23 July 2012

Very high energy density rechargeable lithium air (or Li-O2) batteries are of great interest for future electrified transportation because at best their practical energy density could approach that of current gasoline engined vehicles (after factoring in tank-to-wheel efficiencies). However, researchers are still looking at a multi-decade development cycle for the technology, which can be embodied in a several different architectures. (Earlier post.)

Operation of a rechargeable non-aqueous Li-O2 battery depends on repeated and highly reversible formation/decomposition of Li2O2 at the porous cathode on cycling. As described in a paper published in the journal Science, a team at the University of St. Andrews (Scotland) led by Dr. Peter Bruce has now demonstrated this is possible. Using a dimethyl sulfoxide (DMSO) electrolyte and nanoporous porous gold electrode (NPG), they crafted a cell with 95% capacity retention from cycles 1 to 100) and with >99% purity of Li2O2 formation at the cathode, even on the 100th cycle, and its complete oxidation on charge.

A typical rechargeable non-aqueous Li-O2 cell comprises a lithium metal anode; a non-aqueous Li+-conducting electrolyte; and a porous cathode, the authors note. Operation depends on the reduction of O2 at the cathode to O22–, which combines with Li+ from the electrolyte to form Li2O2 on discharge, with the reverse reaction occurring during charging.

An issue of concern with any battery or chemical/electrochemical reaction is side-reactions, particularly on the first cycle. A key question, the authors say, is the extent of such side-reactions—i.e., whether this is sufficiently small compared with the amount of electrolyte used in practical cells, and whether the extent increases on cycling.

Previous efforts have resulted in only partial Li2O2 formation/decomposition and with limited cycling. The St. Andrews team reported no evidence of any decomposition products. Differential electrochemical mass spectrometry (DEMS) also confirmed that discharge was overwhelmingly dominated by Li2O2 formation.

Furthermore, the data indicated that the kinetics of Li2O2 oxidation on charge is approximately 10-fold faster than on carbon electrodes.

The charge to mass ratio on discharge and charge is 2e/O2, confirming that the reaction is overwhelmingly Li2O2 formation/decomposition. It has also been shown that such electrodes are particularly effective at promoting the decomposition of Li2O2, with all the Li2O2 being decomposed below 4 V and around 50% below 3.3 V and at a rate approximately one order of magnitude higher than on carbon.

Although DMSO is not stable with bare Li anodes, it could be used with protected Li anodes. Nanoporous Au electrodes are not suitable for practical cells, but if the same benefits could be obtained with Au coated carbon then low mass electrodes would be obtained, although cost may still be a problem.

A cathode reaction overwhelmingly dominated by Li2O2 formation on discharge, its complete oxidation on charge and sustainable on cycling, is an essential prerequisite for a rechargeable non-aqueous Li-O2 battery. Therefore, the results presented here encourage further study of the rechargeable non-aqueous Li-O2 cell, although many challenges to practical devices remain.

—Peng et al.

Resources

  • Zhangquan Peng, Stefan A. Freunberger, Yuhui Chen, and Peter G. Bruce (2012) A Reversible and Higher-Rate Li-O2 Battery. Science doi: 10.1126/science.1223985

July 23, 2012 in Batteries | Permalink | Comments (7) | TrackBack (0)

TrackBack

TrackBack URL for this entry:
http://www.typepad.com/services/trackback/6a00d8341c4fbe53ef016768aedf57970b

Listed below are links to weblogs that reference Univ. of St. Andrews researchers show reversible, higher-rate non-aqueous Li-air battery using gold cathode and DMSO electrolyte:

Comments

It look interresting but still hydrogen fuelcell looks more efficient. It's probably another trick from big oil where with their car manufacturer friends they always postpone hydrogen and promise endlessly battery breakthrus that never happen in real life and while doing so for a lot of years then they are doing their petrol sales while we wait for a theoritical battery.

Also these batteries just barely can move for a little while for few miles a small car while hydrogen on the other hand can move cars and trucks and also trains, big trucks, airplanes and ships.

This technology brainwash game is still handle solely by big oil and paid journalists and they are not interrested in anything except costly petrol and they just give a show of false news.

A D you are wrong H2 is a scam organized by big not the opposite, big oil hates batteries. As for fuel cells becoming the mainstream any time soon, dream on it...it won't happen neither H2 economy.

I'd love to see renewable energy eggs in many baskets, but auto/oil has used fuel cells to con the public/taxpayer "research" grants(Bush Hydrogen Initiative..) decades and counting.

Should hydrogen fuel cells ever be economical, H2 distribution will make them uneconomical.

Meanwhile, bigger and bigger players report more and more battery/EV advances.

Should oil prices double(harem updates, wars, whatever) - EVs will just keep looking better and better - selling more and more.

@ Kelly,

Agreed...but what if oil prices stay the same, and CNG comes down in price even more because of fracking?

Where is the pressure to go electric in the next 7 years?

Good Point, HealthyBreeze.
As more and more alternative-fueled vehicles will gain market share and will decrease petroleum consumption, the oil price will come down and down...since expensive off-shore oil will no longer be needed...

Believe it or not, Battery-electricity in the form of LiFePO4 is already costing 1/2 as much as gasoline at $3.5/gal per kWh delivered to the drive shaft. H2-FCV at $49/kWh of FC stack is already at price parity with ICEV at current gasoline prices. A PHEV is a good way to overcome the "range-anxiety" associated with a BEV while still reaping the low-cost benefit of a BEV.

Because of the economic parity of PEV's (Plugged-in EV) and FCV's to ICEV's at this point in time, and because of worsening of GW and climate extremes/ severity, a plan should be made to gradually phase out the use of fossil fuels in surface transportation as well as in electrical generation. This will ensure the continued growth of PEV's.

All supporters of PEV's and FCV's should join together to help promote the change to protect our environment and our future generations, instead of casting doubts on rival ZEV technology. We as humanity, were able to sucessfully phase out CFC. We should be able to do the same for fossil fuels. We all should stick together.

I should further emphasize that a H2-FCV and a PEV should be viewed as brothers in the same family and not as enemies. Both will complement each other nicely. This is because a all-renewable-energy economy will require considerable amount of bulk seasonal energy storage in the form of H2.

--a H2-V is thus a convenient way to utilize the energy storage of H2, and is more efficient than a PEV if a PEV is to be charged from the electricity made from H2 oxidation in the winters or in windless nights, or in calm and cloudy days.

--a PEV, on the other hand, can be 2-3 times more energy efficient than H2-V if charged directly from renewable-energy electricity as it is being produced. V2G is a great way to modulate the intermittency of solar and wind energy.

Most important of all, a push toward an all-renewable-energy economy and transportation will create a lot of jobs and will provide a much-need economic growth that the world is badly needed right now!

Now here's an idea that worth it's weight in gold.

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Working...
Your comment could not be posted. Error type:
Your comment has been posted. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.

Working...

Post a comment

Green Car Congress © 2014 BioAge Group, LLC. All Rights Reserved. | Home | BioAge Group