Green Car Congress  
Home Topics Archives About Contact  RSS Headlines

« A123 Systems to supply Li-ion packs to Tata Motors for hybrid electric transit buses and other commercial vehicles | Main | Controlled Power Technologies and Advanced Lead-Acid Battery Consortium to unveil LC Super Hybrid at Geneva show; low-cost “micro-mild” demonstrator »

Print this post

ANL team develops new class of Li- and Na- rechargeable batteries based on selenium and selenium-sulfur; greater volumetric energy densities than sulfur-based batteries

1 March 2012

Sexsy
Cycling performance of Li/SeS2−C, Li/Se−C, Na/SeS2−C, and Na/Se−C systems. Credit: ACS, Abouimrane et al. Click to enlarge.

Researchers at Argonne National Laboratory have developed selenium and selenium–sulfur (SexSy)-based cathode materials for a new class of room-temperature lithium and sodium batteries. A paper on their work is published in the Journal of the American Chemical Society.

Unlike the widely studied Li/S system, both Se and SexSy can be cycled to high voltages (up to 4.6 V) without failure. Their high densities and voltage output offer greater volumetric energy densities than sulfur-based batteries, opening possibilities for new energy storage systems that can enable electric vehicles and smart grids, according to the ANL team.

The discovery of new electrode materials is key to realizing safe and efficient electrochemical energy storage systems essential to enabling future green energy technologies. Beyond conventional intercalation chemistry, reaction of lithium with sulfur and oxygen (so-called “Li-air” batteries) have the potential to provide 2 to 5 times the energy density of current commercial systems. However, both Li/S and Li/O2 systems suffer from cycling performance issues that impede their commercial applications: Li/O2 cycling is limited by electrolyte decomposition and large cell polarization; Li/S suffers from the low conductivity of S and the solubility of intermediary polysulfide species during cycling.

Here we explore the potential of selenium, a d-electron containing member of group 16 with high electrical conductivity, as an electrode material for rechargeable batteries. We show that Se and mixed SexSy represent an attractive new class of cathode materials with promising electrochemical performance in reactions with both Li and Na ions. Notably, unlike existing Na/S batteries that only operate at high temperature, these new Se and SexSy electrodes are capable of room temperature cycling against Na. Accordingly, Se not only provides opportunities for developing new high performance rechargeable batteries, including mixed chalcogenide systems but also has the potential to enhance our fundamental understanding of batteries.

—Abouimrane et al.

The team built coin cells using carbon nanotube-containing composite Se and SeS2 electrodes (Se−C and SeS2−C) and metallic Li and Na. Among their findings were:

  • The systems exhibited strong cycle life, with repeated cycling up to 100 cycles.

  • The Li/Se−C system sustained a reversible capacity of ∼500 mAh g−1 for >25 cycles at low current density (10 mA g−1, ∼C/60), which reduced to ∼300 mAh g−1 at higher current density (50 mA g−1, ∼C/12) with a small fade for 100 cycles.

  • For Na/Se−C, a lower capacity was observed with an excellent cycle life (265 mAh g−1 at 50 mA g−1)

  • Extension of the cycling potential up to 4.6 V did not adversely impact the electrochemical performance of Li/Se−C, which sustained a capacity of 280 mAh g−1 over 80 cycles (100 mA g−1, ∼C/6). This allows for use of high potential windows, unlike for Li/S, where charging beyond 3.6 V disables any further cycling.

The Selenium-containing electrodes offer several advantages over the widely studied sulfur systems. Some of these are:

  1. Se has electric conductivity, approximately 20 orders of magnitude greater than S. This facilitates cycling with Na at room temperature, while Na/S operation is limited to elevated temperatures (300−350 °C).

  2. Despite a lower theoretical gravimetric capacity, the high density of Se allows for volumetric capacities that are comparable to S.

  3. The Se systems provide higher output voltages than S and, accordingly, higher energy densities, a key advantage in commercial applications. For Li/Se, the output voltage is at least 0.5 V higher for Li/S.

  4. For Na/Se, the theoretical capacity exceeds that observed for Na/S at room temperature.

  5. From a practical standpoint, the toxicity of Se is comparable to S and other common electrode elements (LD50 [median lethal dose]: Se ∼6.2 g; S ∼8.4 g; Co ∼6.7 g; Ni ∼5.0 g), and it is included, in trace quantities, in supplements and personal care items. While the lower abundance (and higher cost) of Se compared to S may impede large scale commercialization, this could be largely offset by using Na rather than Li, and/or by using mixed Sex Sy systems.

    —Abouimrane et al.

    Not only does the Se electrode show promising electrochemical performance with both lithium and sodium anodes, but the additional potential for mixed SexSy systems allows for tunable electrodes, combining the high capacities of S-rich systems with the high electrical conductivity of the d-electron containing Se.

    A preliminary study of a SexSy material showed higher theoretical capacities than the Se alone, with improved performance and conductivity compared to S. For Li/SeS2−C, the discharge capacity is 30% greater than Li/Se−C in the range 0.8 to 4.6 V (512 vs 394 mAh g−1 after 30 cycles, 50 mA g−1 current density).

    SeS2−C can also be cycled with Na at room temperature, with a capacity of 288 mAh g−1 sustained over 30 cycles.

    As Se and S are infinitely miscible, with many readily available solid solutions (e.g., Se5S, Se5S2, Se5S4, SeS, Se3S5, SeS2, SeS7), SexSy materials represent a broad class of new battery electrodes with higher theoretical capacities than Se alone (675−1550 mAh g−1 for systems above) with improved conductivity (and room temperature cycling) compared to S alone. Systems with even lower Se proportions, i.e. SeS20, can be easily prepared.

    In the current drive to discover and optimize materials for electrochemical energy storage, this new class of room temperature Li- and Na-based SexSy rechargeable batteriespaves the way for new, promising opportunities to enable high energy batteries for transportation and grid applications.

    —Abouimrane et al.

    Resources

    • Ali Abouimrane, Damien Dambournet, Karena W. Chapman, Peter J. Chupas, Wei Weng, and Khalil Amine (2012) A New Class of Lithium and Sodium Rechargeable Batteries Based on Selenium and Selenium–Sulfur as a Positive Electrode. Journal of the American Chemical Society doi: 10.1021/ja211766q

March 1, 2012 in Batteries, Li-Sulfur | Permalink | Comments (19) | TrackBack (0)

TrackBack

TrackBack URL for this entry:
http://www.typepad.com/services/trackback/6a00d8341c4fbe53ef0168e83442f0970c

Listed below are links to weblogs that reference ANL team develops new class of Li- and Na- rechargeable batteries based on selenium and selenium-sulfur; greater volumetric energy densities than sulfur-based batteries:

Comments

This may be one of many alternative material for electrodes with higher performance. It is disappointing to see that the world is not producing many more possibilities and that 400+ Wh/Kg batteries are not already being mass produced.

This ain't gonna to make it, it's too complicated and cannot be commercialized, too costly. Also these different battery chemistry needs different fast chargers and don't work in winter. Just in theory alone it don't work so in practice it's even worse. Difficulty to recharge, difficulty with cost and weight and range and recharging. Incompatibility between recharging methods, self depletion, degradation over time, impossible to recycle, customer rejection.

Start proven hydrogen commercialisation right away because it apply to everything, cars, trucks, airplanes, machineries, ships.

Certainly, some type of sulfur based alternative cathode material is the way to go. These news releases however hardly ever have enough information in them to make a reasonability determination. Nevertheless, with the successes that people are having with silicon anodes, it will be necessary to match that capacity on the cathode side. Additionally, the current crop of cathode materials are the major material cost in batteries. Transition metals are never cheap, although moving to manganese and making it work is a step in the right direction(vs. nickel and cobalt). However, there's not much cheaper than sulfur. I wish they would have mentioned if polysulfide miscibility is still an issue. I suspect so. Hey AD, "The batteries are coming".

Maybe it is good that people who are SO certain that they have THE answer are not the ones making the decisions for millions of people.

"Start proven hydrogen commercialisation right away because it apply to everything, cars, trucks, airplanes, machineries, ships." - fortunately, we are living in the tenth year of "proven hydrogen commercialisation" - all 16 of um - http://www.greencarcongress.com/2012/02/army-20120223.html

SJC, given your GTL fixation I wouldn't talk if I were you.

I do not claim it is THE answer, but some claim BEVs are.

"All the forces in the world are not so powerful as a new idea whose time has come." — Victor Hugo

"A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it." — Max Planck

http://bluefuelenergy.com/

@AD:
-hydrogen tunnels through solid steel
-hydrogen's flame is invisible (safety hazard)
-hydrogen is HIGHLY combustible (safety hazard)
-hydrogen is energy very intensive to produce

Fossil to electricity: 36%
Fossil to battery (charging): 90%
Battery to wheels: 90%
Total: 29%

Fossil to electricity: 36%
Electricity to hydrogen: 66%
Hydrogen to wheels: 40%
Total: 9.5%

IIRC, the bleed rate for hydrogen from steel tanks is something like 6% per day.

Electricity to hydrogen


Man is capable of infinite self delusion. - Me

Greenplease, chemical reformation of fossil fuels to hydrogen is far more efficient than 24%... which does not make it a good idea.  Bad arguments against a bad idea don't help.

Greenplease,

I support your arguments because of being concentrated and short. I am going plague them (if you allow me) in the future. Engineer-Poet's speculation concerning chemical reformation could be applicable in academic circles and suggests discussions which fossils would be taken as reference. May be natural gas. But it not makes any sense transforming natural gas into hydrogen and then burn it. It is better burn it directly or transforme into other synthetic fuel as GTL or DME. And so on... Therefore I like you argumentation. And as soon as I see AD's hydrogen I am going past and copy answer.

GTL is happening now, hopefully NG remains low cost... $0.60 worth of NG per gallon of synthetic gasoline sure is nice.

Herm is correct, even if it takes 3 therms of natural gas for 1 gallon of synthetic gasoline, natural gas sells for less than 30 cents per therm wholesale right now.

It can take $3 worth of oil to refine a gallon of gasoline versus less than $1 worth of natural gas to synthesize a gallon of gasoline.

Since we have natural gas in the U.S. and import a LOT of oil, it makes sense to synthesize gasoline using natural gas.

There are those that seem to believe that arguing brings about the truth, arguing brings about conflict, only rational debate can reveal truth.

even if it takes 3 therms of natural gas for 1 gallon of synthetic gasoline
You think that a system currently supplying 22 quads/yr of natural gas could make a significant dent in a petroleum product market of ~36 quads/year (gasoline alone ~15 quads/year) despite 2/3 losses in conversion?

There's a word for that, and you won't find "sensible" in its synonyms in the thesaurus.

natural gas sells for less than 30 cents per therm wholesale right now.
There's a bubble economy in N. American gas; the breakeven point for dry gas production is north of 70¢/therm.  The producers are on a binge financed by borrowing, not cash flow; none are profitable, and consolidation is starting.  When the game of musical chairs suddenly stops, you'll see the gas glut disappear and prices double overnight.

GTL makes economic sense, so it will happen.

Despite the pseudo-religious ectasy over H2 and fuel cells, it is not and never will be economic, so it won't happen.

GTL does not make sense.  You can burn the gas directly, with neither the conversion losses nor all the expensive chemical plants.  It might make sense to convert 10% of methane to DME to provide ignition in a diesel engine, but the other 90% methane can be carbureted directly.

The great thing about converting vehicles instead of building new chemical industries is that the vehicles turn over several times as fast.

We need to reduce our imports of OPEC oil, turning natural gas into gasoline is one way to do that.

It is being done, it will be done and just because some people are critical of anything they do not like, that will not change the outcome.

You can not will the future, no matter how big your ego is.

You can't out-rhetoric physics without subsidies, and good luck getting any subsidies when the country's broke.

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 © 2017 BioAge Group, LLC. All Rights Reserved. | Home | BioAge Group