New Type of Molten Air Battery Promises Energy Capacity Way Beyond Even Lithium Air

3 years ago by Eric Loveday 29

Molten Air Generalization Graphic

Molten Air Generalization Graphic

Battery technology is constantly evolving.

Charge / Discharge Cycle of Molten Air

Charge / Discharge Cycle of Molten Air

Today’s lithium-ion battery tech won’t be around decades from now.  It’ll likely give way to either solid-state or lithium-air.

But what’s the future hold beyond that?

Could it be molten-air?

Researchers at George Washington University believe that molten-air batteries could be in our future and, under the guidance of Dr. Stuart Licht, published a paper on the properties and values of molten-air technology.

The researchers firmly believe that molten-air tech offers the highest intrinsic electric energy storage capabilities of any known battery technology.

According to Green Car Congress, Licht and his colleagues show 3 examples of molten-air’s electron transfer chemistry:

“These are the iron, carbon and VB2 molten air batteries with respective intrinsic volumetric energy capacities of 10,000 (for Fe to Fe(III)); 19,000 (C to CO32-) and 27,000 Wh liter-1 (VB2 to B2O3 + V2O5), compared to 6,200 Wh liter-1 for the lithium-air battery.”

Stuart Licht himself says this in the published paper:

“In 2008 a zirconia stabilized VB2 air battery was presented.  This 11e- (eleven electron) per molecule, room temperature, aqueous electrolyte battery has the highest volumetric energy capacity for a battery, with an intrinsic capacity greater than that of gasoline and an order of magnitude higher than that of conventional lithium ion batteries. The challenge has been to recharge the battery; that is to electrochemically reinsert 11e- into the battery discharge products. Here, this challenge is resolved through the introduction of a new class of molten air batteries.”

“…Unlike prior rechargeable molten batteries, the battery is not burdened by the weight of the active chargeable cathode material. The rechargeable molten air electrode instead uses oxygen directly from the air to yield high battery capacity. This electrode will be shown to be compatible with several high capacity multiple electron redox couples. Three demonstrated new batteries chemistries are the metal (iron), carbon and VB2 molten air batteries with intrinsic volumetric energy capacities greater than that of the well known lithium air battery due to the latter’s single electron transfer and low density limits.”

Could molten-air be the future?  If so, where will electric vehicles be in terms of miles per kWh after this technology takes over?

Source: Green Car Congress

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29 responses to "New Type of Molten Air Battery Promises Energy Capacity Way Beyond Even Lithium Air"

  1. Aaron says:

    Molten air? The article says “room temperature”, but I can’t help but imagine the old sodium-sulphur batteries that used high temperature, molten sodium. Maybe the word “molten” is messing me up.

    1. Jesse Gurr says:

      Research paper here:

      Very intersting. The lowest temp i saw was 400 deg C up to 800 deg C.

  2. Priusmaniac says:

    No way this can compete simply because it is the KWh/Kg that actually count for a moving object like a car, not the KWh/liter. So Lithium remains better on that account.

    This doesn’t mean there is no use for it but not in cars.

    The Aluminum air battery is more intresting.

    1. Ambulator says:

      Both kWh/kg and kWh/L are important, and I would even say kWh/L is a bit more important.

      I’m struggling with the ‘molten’ part, though. Liquid iron in a moving car sounds dangerous.

  3. Jay Cole says:

    I’ve already got like 2 converted EVs with molten-air electron transfer technology, although I did a little optimization work on it myself (it’s a hobby) to get the VB2 intrinsic volumetric energy capacities to like 28,723 Wh liter-1 (VB2 to B2O3 + V2O5) after like 1,241 cycles.

    /its pretty awesome

    1. GeorgeS says:

      Are you kidding?

      1. Jay Cole says:

        Heeh, yeah I am just kidding George,

        …I’ve only have 1 molten-air battery powered car, (=

        1. GeorgeS says:

          well how should I know. You EV guys get pretty whacked out over the edge sometimes.

          1. Jay Cole says:

            That’s true, (=

    2. shawn Marshall says:

      :>) Wow!! That’s a blast of static from the past.

      1. staff says:

        Sometimes he can’t be controlled. We are working on some sort of special collar!!!

        1. GeorgeS says:

          No fair Jay, you posted this and just pushed the staff button.

    3. Priusmaniac says:

      It could be interesting after all in a certain application where volume must be small like in an electric hypersonic plane. You can make an electric plane with an electrofan but if you want to get at higher speed you need to inject much more energy to increase the exhaust speed. This can be done by pumping microwaves as a burner replacement and subsequently magnetically push it out through a powerful MHD superconducting magnet. This is all taking enormous amounts of energy so the preferred route is the Superconducting Magnetic Energy Storage, but that one has his own challenges and has not been up to the task so far. In this case a molten salts system could perhaps be an alternative. You could have the molten salts associated with oxygen to drive the electric hypersonic plane, first with oxygen from the air then with oxygen from an on board tank. The compact storage form of the battery would reduce the cross section of the plane perhaps just enough to allow the drive to cancel the drag making the system feasible altogether. Of course you would not be able to fly for long but it just take a few minutes to go quite a distance at hypersonic speeds and it only takes 10 minutes to reach orbit. If you need 5 GW you need to store about 850000 KWh 28723 Wh/liter would mean 30000 liters of molten salts which is thinkable aboard a plane while still keeping an acceptable low cross section. Now the remaining problem would be weight. That is actually OK only you go hypersonic because you have an excess of lift but it is a real challenge to take off in the first place. Perhaps you could use a help from stratolaunch to get off the ground.

      1. Jesse Gurr says:

        Or maybe some sort of maglev launching ramp?

        1. Priusmaniac says:

          Yes, but for both starts systems there remains a problem when the plane comes back. Unlike a rocket the molten salts are still in there and so is the weight. How is it going to come back?

  4. Schmeltz says:

    The trouble now will be to find an active volcano and capture enough molten air for the mass market…Hawaii, here we come. 🙂

  5. Dan Frederiksen says:

    Ehhhh, what? is this a joke? is green car congress mocking the parrot news sites who copy without question?
    for one, an air electrode seems somewhat unlikely as air is a piss poor conductor 🙂
    and air is never molten 🙂 it can be liquid but that’s extremely cold and otherwise it’s gaseous.
    So WTF is going on here?? 🙂

    1. Priusmaniac says:

      There simply is a catch in the sense that it is a somewhat abusive abbreviation of a molten salts – air battery, but molten salt being too long, it is shorten in molten air. But of course you common sense is correct, there is no such thing like molten air. Although, now that I think about it you could think of one very special situation. A Nitrogen Oxygen crystal at -270°C that would be solid and you would melt that solid at say -265°C in a liquid air form. I wonder what kind of explosive rocket fuel a crystalline Hydrogen Oxygen solid would give when it is molten just in front of the rocket chamber to ignite burn and eject in the rocket nozzle!

  6. kdawg says:

    molten air = plasma (or what my dog produces after eating certain foods)

    1. vdiv says:

      Exactly! Glowing batteries are normally considered rather disastrous 🙂
      Walking a dog after his dinner nearby one of these would be rather apocalyptic 😉

      Plasma is rather conductive.

  7. Randy Bryan says:

    I image first uses in trucking and marine and military applications. Later in cars.
    KWH/liter is the more important measure as battery weight is less important with regeneration.
    Also, since electric motors are typically 3-6 times more efficient than ICE, such a battery with energy density in excess of liquid gasoline could offer quite a package.
    No mention made in the Release about power density or charge time.
    Looking forward, maybe the physics of molten metals oxidation can be re-engineered to happen in lower temperature materials, with research.

  8. Roy_H says:

    What’s the date today, April 1st?

    Definition: mol·ten [mohl-tn] Show IPA
    1.a past participle of melt.
    2.liquefied by heat; in a state of fusion; melted: molten lead.

    So I have a very hard time believing you can heat air (a gas) and produce a liquid.

    Went to couldn’t find any reference to this new battery.


    1. Roy_H says:

      Well, after deriding this as a hoax, I have done some additional research and come up with this:

      The proper name is “Molten Electrolyte – Air Battery” and short forms can leave out critical information. The tests were performed at a very low C rate of about 0.05, and higher rates lowered the already low 1 volt operating level. EVs typically require an average of about 1C and 10C on heavy acceleration. Non-the-less this is still a very exciting discovery, and one can hope that there will be various improvements as research continues in the next few years.

  9. Brad B says:

    I cant wait. If you used the same volume used in the Model s for its battery and replaced it with this “VB2 molten air ” battery you would have an unrecharged range of 11,925 miles, sweet. An other way of looking at it is that a 500 mile battery with this tech would take up a little more than a gallon of volume. If the battery was contained in a high temp vacuum vessel it would barely be warm to the touch and the battery could use its own power to keep its self hot. With the right engineering, it could be made to work in an EV, once the battery itself is perfected.

  10. drpawansharma says:

    Imagine a world where a shoebox sized battery would push a car a thousand miles a charge. Imagine a world where energy storage is so cheap practically everyone is off grid. Imagine a world where large cities do not have a hint of smog. Imagine a world where population is a third of what it is now. Imagine a world where there is no religion. Imagine a world where there are no wars. Please let that world come within my lifetime. Please let that world be ours.

    1. Rick says:

      That world will not come in my lifetime, because I’d probably be one of the 2/3 of the world’s population you’re willing to sacrifice to make it happen. 😛

  11. MDEV says:

    Guys what is the next real step fwd with batteries? What technology let’s say 5 years in the future.

    1. Brad B says:

      Envia is probably the closest, with triple the performance of the current Tesla cells on track to be available in quantity in 2015. Chevy has bought into them in a big way and has claimed it may have a three hundred mile Spark by around that time frame. If that battery, which according to Evia will be available in the 18650 form factor, were to be fitted into the Tesla pack, it would give the car a 750 Mile range. Although even the capacity of “classic” lithium ion has almost doubled the capacity of what is available in the present Tesla Model S. Tesla uses 3100 mAh cells, and you can currently buy, off the shelf 18650’s, for $1.60 per cell in 10 packs that store 5000 mAh each. If Tesla were to upgrade to this battery tech right now, they would achieve 425 mile EPA range. The cells would cost no more than $7000 in the quantities that Tesla would buy them. In 5 years, lithium silicon nano-wire cells will probably have about 5 times the capacity of the present Tesla battery 18650 cells or about 15,000 mAh storage. The company is just beginning to sell batteries, though not that energy density yet, but I firmly believe they will, and be substantially cheaper per watt hour. There are a few others that may get to that energy density in five years and be competitive , but I think these are the most likely.

      1. Roy_H says:

        Could you provide a link to these 5Ah cells at $1.60 each? I suspect these are the type that have a very large voltage drop over the useage cycle. Either the car would have excellent acceleration and top speed at full charge then degrade to mediocre or poor acceleration and top speed as the pack discharged, or more money has to be spent on electronics to pump up the voltage when it is low. Tesla (and others) may not consider this trade-off worth while.