Energy

"Fool's gold" nanocrystals present cheap, abundant alternative to lithium in batteries

"Fool's gold" nanocrystals pre...
Empa researchers have demonstrated the use of pyrite (fool’s gold) as a cathode material
Empa researchers have demonstrated the use of pyrite (fool’s gold) as a cathode material
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Electronmicroscope image of Pyrite nanocrystals
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Electronmicroscope image of Pyrite nanocrystals
Diagram of the Na-Mg hybrid battery
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Diagram of the Na-Mg hybrid battery
Empa researchers have demonstrated the use of pyrite (fool’s gold) as a cathode material
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Empa researchers have demonstrated the use of pyrite (fool’s gold) as a cathode material

As energy production moves towards solar and wind-powered alternatives, battery systems to store intermittently-produced electricity have never been more important. Unfortunately, many of the materials needed to make high-performance batteries for this purpose are rapidly diminishing and becoming increasingly expensive as a result. Now researchers from Empa and ETH Zurich have created a new type of storage battery that is made from a range of cheap and abundant materials and shows promise for high-efficiency performance.

The prototype battery uses nanocrystals composed of iron sulfide, better known as pyrite or "fool's gold", as the cathode, sodium as the electrolyte and magnesium for the anode. All of these ingredients are relatively inexpensive and abundant, with materials such as iron sulfide nanocrystals being made by simply milling sulfur with dry metallic iron, whilst a kilogram of magnesium is some 15 times cheaper than a comparable quantity of lithium. In addition, iron, magnesium, sodium, and sulfur are 4th, 6th, 7th, and 15th in order of abundance on Earth by mass, respectively.

Electronmicroscope image of Pyrite nanocrystals
Electronmicroscope image of Pyrite nanocrystals

Further savings could also be realized in the construction of the battery, as aluminum foil is perfectly adequate to accumulate and conduct electricity from it, where as lithium ion (Li-ion) batteries need comparatively expensive copper foil to perform the same role.

In use, when the battery discharges, sodium ions suspended in the electrolyte move towards the cathode, where they accumulate. When the battery is recharged, the pyrite re-releases the sodium ions back to the electrolyte. Verification of the operation of this sodium-magnesium hybrid storage cell has already been demonstrated in the laboratory, with the test battery already having achieved 40 charging and discharging cycles with no change to its performance.

Diagram of the Na-Mg hybrid battery
Diagram of the Na-Mg hybrid battery

Though the output of the new battery is presently lower than that of a comparable size Li-ion, the researchers believe that the inexpensive and scalable nature of the new device is such that it could be used to construct enormous storage cells for power stations. One such suggestion from the scientists is that a sufficiently large battery might be used to temporarily store an entire year's output from a nuclear power station, for instance. In essence, if a big enough battery is constructed, it could potentially store many terawatt-hours of energy.

"The battery's full potential has not been exhausted yet," said Prof. Dr. Maksym Kovalenko, who teaches at ETH Zurich's Department of Chemistry and Applied Biosciences as well as researching at Empa. "If we refine the electrolytes, we're bound to be able to increase the electric voltage of the sodium-magnesium hybrid cell even further and to extend its cycling life."

Investors are being sought to support further research and bring the technology to market."

The results of this research were recently published in the journal Chemistry of Materials.

Source: Empa

11 comments
Tom Lee Mullins
I think this will help batteries become more affordable. I think this is good for all things that are battery powered.
watersworm
One such suggestion from the scientists is that a sufficiently large battery might be used to temporarily store an entire year's output from a nuclear power station, for instance. ??? Waow may it be true !!! Seams so incredible !
Freyr Gunnar
How do we dig minerals and build those batteries after Peak Oil?
Mel Tisdale
@ Freyr Gunnar Peak Oil does not mean that we have run out of oil. It means that we have reached a peak in the amount we can extract per day (or per whatever). That means that there will come a time when demand exceeds supply and unless we can reduce that demand, we will not be able to do all the things we used to do before we hit Peak Oil's limit to supply. Then, of course, there is Fracking to consider, but perhaps on another day, when all the Fracking hype has died down and we can face up to reality. For homework, surf the web for Peak Prosperity's 'The Crash Course' or Gail Tverberg's 'Our Finite World.'
Nik
Magnesium is inflammable, so what are the chances of battery using it catching fire?
MarylandUSA
So give us some number. Nominal voltage? Voltage under a 1C load? Resistance? Capacity will surely improve, but voltage and resistance are more or less fixed.
tob
"unfortunately many of those materials are rapidly diminishing.." What could that possibly mean? We are sending them into outer space so they no longer exist on earth? "a kilogram of Magnesium is some 15 times cheaper.." How can something be 15 times cheaper? Presumably one times cheaper would be zero or free. .
jerryd
More hype and lies from grant seekers. There are plenty of low cost materials to make batteries from that perform better than this one. And how will well mine the materials to make them with oil, simple, clean electricity as many mines already use. Most metals too are now made, refined with electricity.
AbsolutJohn
Colin, great article.... I think the main take-away for all is: "...researchers believe that the inexpensive and scalable nature of the new device is such that it could be used to construct enormous storage cells for power stations.... In essence, if a big enough battery is constructed, it could potentially store many terawatt-hours of energy." Commercial take-aways -feel free to connect more dots... 1. Home energy usage - replacing emergency generators and enabling battery backup of entire neighborhoods. 2. Military hardware - instant long-term FOB power 3. Somewhere in Texas, someone will take this to where this needs to go. "Texas?", you say? Yes. Texas has an electrical grid that is independent from the rest of the U.S. This is not by accident. This is potentially a way of utilizing the over-abundance of energy they are producing by utilizing the battery storage almost as a huge capacitor, keeping it separate but allowing massive amounts of energy to be sold to the rest of the U.S. grid. thoughts...?
piperTom
Promising, yes, but 40 charge/discharge cycles is nothing. Even 400 is weak; call back when it's 4000. To tob, "15 times cheaper" is, indeed, nonsense. In context, it has to mean the ratio of cost is 15 and magnesium is the cheaper. To Nik, magnesium may be flammable, but so is lithium. We can deal with it. To author: a whole year's nuclear energy in storage is possible already; it's just prohibitively expensive ... and useless.