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Arndt Remhof's team has developed a solid electrolyte that facilitates good mobility of sodium ions at 20 degrees. This last point is crucial: ions require a source of heat in order to move, and inducing a reaction at room temperature poses a technical challenge. The electrolyte is also non-flammable and is chemically stable up to 300 degrees, which addresses the various safety concerns associated with lithium-ion batteries. Hans Hagemann's team at the University of Geneva has been working in parallel to develop cheaper technology for the production of this new solid electrolyte.
Unlike lithium, there are huge reserves of sodium: it's one of the two components of table salt. "Availability is our key argument", says Léo Duchêne of Empa and first author of the research paper. "However, it stores less energy than the equivalent mass of lithium and thus could prove to be a good solution if the size of the battery isn't a factor for its application."
Magnesium: the perfect but complex material
The same team has also developed a solid magnesium-based electrolyte. Until now, very little research had been done in this field. The fact that it is much more difficult to set this element in motion doesn't mean that it is any less attractive: it's available in abundance, it's light, and there's no risk of it exploding. But more importantly, a magnesium ion has two positive charges, whereas lithium only has one. Essentially, this means that it stores almost twice as much energy in the same volume.
Some experimental electrolytes have already been used to stimulate magnesium ions to move, but at temperatures in excess of 400 degrees. The electrolytes used by the Swiss scientists have already recorded similar conductivities at 70 degrees. "This is pioneering research and a proof of concept," says Elsa Roedern of Empa, who led the experiments. "We are still a long way from having a complete and functional prototype, but we have taken the first important step towards achieving our goal."
The energy density of a magnesium electrolyte would solve the EV range problem, if it is double lithium's.
(Score: 0) by Anonymous Coward on Wednesday May 03 2017, @09:34AM
So, ten years?
(Score: 1, Insightful) by Anonymous Coward on Wednesday May 03 2017, @09:42AM (23 children)
Sodium may be abundant, but anyone here recall their high school chemistry? Sodium burns like mad and reacts violently with water. Magnesium is a bit better, but once on fire it is unstoppable. While these researchers are playing with the volatile metals, why not look at phospheros? Maybe it packs even more punch per gram ;)
(Score: 2, Funny) by Anonymous Coward on Wednesday May 03 2017, @09:56AM (2 children)
So is lithium (flamable not aboundant). Phospheros? Never heard about this element.
(Score: 2) by Immerman on Wednesday May 03 2017, @04:54PM
Nice job of making fun of a slight misspelling of phosphorus. Well done! You'll find your award plaque waiting for you at the bottom of the nearest outhouse.
(Score: 2) by Fluffeh on Wednesday May 03 2017, @09:35PM
Phospheros? Never heard about this element.
Oh, it's a city in the upcoming season of Game of Thrones...
(Score: 2) by driverless on Wednesday May 03 2017, @10:11AM (14 children)
That was my reaction as well:
The same team has also developed a solid magnesium-based electrolyte. [...] it's available in abundance, it's light, and there's no risk of it exploding
It does, however, burn spectacularly well.
I wonder why all these battery technologies use such dangerous elements, lithium, sodium, and magnesium. If they used RTGs we wouldn't have these problems, plutonium isn't especially explosive or flammable.
(Score: 4, Interesting) by VLM on Wednesday May 03 2017, @12:57PM (5 children)
I wonder why all these battery technologies use such dangerous elements
The optimist sees an atom with a loosely attached electron and says he can control that loosely attached electron quite easily and make a hell of a battery.
The pessimist sees an atom with a loosely attached electron and says being loosely attached if that thing gets out of control its going to do crazy stuff like snap water molecules in half to bond with the oxygen making a hell of a hydrogen fire, etc.
The above is a gross simplification.
Nuclear fission is the same deal in a hand wavy sense. The stuff thats easy to split is quite unstable even making a large pure pile of it would be very dangerous.
(Score: 2) by Immerman on Wednesday May 03 2017, @05:09PM (4 children)
I agree that fission has it's own hand-wavy double-edged sword, but that has little to with RTGs. Radioisotope Thermoelectric Generators generate energy by capturing the heat generated by nuclear decay, not fission. There is no splitting of atomic nuclei going on, no possibility of chain reactions, just unstable nuclei spontaneously ejecting particles as they decay to a more stable state.
Of course you do still have a bunch of radioactive material in a sealed container, and it's likely to be an issue if it breaks open, but that's a completely different risk more closely related to managing nuclear waste than operating a reactor. In fact, I believe nuclear "waste" is a primary source of fuel for most RTGs, though it can be produced in other ways as well. Pretty much by definition any material radioactive enough to generate a useful amount of heat will have long since decayed to nothing over the several billion years since it was created. Which is why you can eat uranium ore without risk of radiation poisoning (though I don't recommend it - the heavy metal poisoning will still get you)
(Score: 2) by VLM on Wednesday May 03 2017, @06:46PM (3 children)
the heavy metal poisoning will
Yeah don't forget bioavailability or biological half life. A little bottle of warm to the touch iodine that's permanently liquid sounds like a cool cabinet of curiosities item but thats just not cool.
And every sword having double edges sure there's an isotope of Argon if I remember correctly with a delicious tasty couple hundred year life weak beta (electron) emitter. So a pure source of electrons and argon's biological activity is nil. Sound great other than the breakdown product is potassium which is going to be conductive thus shorting the blasted thing out from the inside AND your bananas (and innards) are going to glow in the dark because its delicious potassium. So both the source and all the byproducts have to be safe. Its harder than it looks for direct conversion!
There's a plutonium isotope thats perfect for thermal RTGs other than the whole "kaboom" thing.
(Score: 2) by Immerman on Wednesday May 03 2017, @08:41PM (2 children)
Bio-availability is certainly a concern, though only for significantly radioactive isotopes, and we would be wise to select isotopes (and decay chains) that avoid it as much as possible.
As for your argon complaints, they felt really off intuitively, so I did a little research starting here (https://en.wikipedia.org/wiki/Isotopes_of_argon) to knock a few points
Firstly - Argon is a noble gas, so you'd have to have a really large or highly pressurized RTG to collect enough of it in one place to be useful. And a pressurized container filled with radioactive gas is probably a bad idea to begin with. But maybe you could stabilize it as a solid somehow - let's run with that.
Secondly, something with a half-life of centuries (like Argon 49 at 269 years) probably isn't a good choice for an RTG in most applications outside of interstellar probes. The longer the half-life, the less radioactive it is, and the less energy you can extract from the decay of a given sample size. But hey, there's also Argon 42 with a half-life of only 32.9 years, that's going to be more usefully radioactive. (Most other known Ar isotopes have half-lives measured in milliseconds, with a few in seconds and one of several days - all too short for a useful RTG) Both undergo beta decay into a potassium atom of the same mass.
Potassium 49 would be a wonderful byproduct, as it's stable and thus presents no radiation hazard at all - radioactivity isn't "contagious" unless you're emitting neutrons that can enrich the surrounding material. Potassium 42 on the other hand is pretty highly radioactive, with a half-life of only 12 hours. But that same half-life means it won't accumulate in the device. Instead it will rapidly decay into stable calcium 42.
So basically, an Argon RTG would be pretty frigging safe in terms of radioactivity. As for the conductivity of Potassium or Calcium being a problem - I don't see why. There's no reason you couldn't surround the RTG core with an electrically insulating layer - after all it's just a convenient heat source, there's no need for any electrical components that could be shorted out.
As for Plutonium 238, the isotope often chosen for RTGs because of it's decent power output (~0.54W/gram) and low shielding requirements. It's an alpha emitter, aka helium nuclei, which don't penetrate much. And it's daughter atom is U234, which is pretty stable with a half-life of 246,000 years. There's really not a whole lot of accidental "boom" potential - it doesn't emit neutrons when decaying, so it can't start a chain reaction - on it's own there is no critical mass.
Of course it is still a fissionable material, so once you assemble a nice concentrated chunk of it you make it easy for someone else to stick it in a bomb that contains the requisite neutron-emitting "trigger" and neutron mirrors to sustain the reaction. Though they still have to build such a bomb, which is arguably almost as difficult as creating the Pu-238 in the first place.
(Score: 2) by VLM on Wednesday May 03 2017, @09:24PM (1 child)
Its just so nice to have something biologically irrelevant other than mere proximity like argon. Agreed the engineering would be a pain. But noble gasses are just so biologically uninteresting. Its not like inhaling tobacco smoke or something LOL.
Yeah 42K is really the question isn't it where K is bioavailable and its going to be generated for decades/centuries if theres 42Ar contamination that isn't blown away physically but the radiation exposure ends in a couple days regardless of biological half life. Thats what I like about 39Ar sure the activity is lower but who cares Ar is not biologically relevant and 39K as the result is just delicious stable. It boils down to what happens when there's a leak, I would not be happy working next to a 42Ar tank with a possible theoretical slow leak 8 hours per day. 39Ar, sure, no worries.
As far as electrical conductivity there were 60s experiments with direct conversion. A capacitor with a beta emitter treated plate slowly charges itself like a constant current source is plugged into it. Cool. I was thinking radio-battery not technically RTG as you mention. If you're going thermal thats less efficient than direct conversion and you gotta get rid of a lot of heat.
By "boom" the problem with a Pu source is the lung cancer if a literal hand grenade or car bomb goes off. I guess it matters where you intend to use these batteries. Probably a bad choice for a residential TV remote control or car battery. Good for spacecraft, sure. I just don't see a Pu source like that leaving military / NASA type hands. Where are you putting these batteries?
(Score: 2) by Immerman on Wednesday May 03 2017, @11:20PM
Oops, right, Ar39, not 49.
Fair point on leakage, though I have no idea how bioavailable atomic K is - in fact a quick search suggests not a whole lot is known about potassium bioavailablity in general. Still, most people probably aren't going to want to sit next to a substantially radioactive source for many hours a day regardless. In fact breathing radioactive argon 8 hours a day would likely be rather cancer-inducing in it's own right - no need for it to stick around if you keep breathing a fresh supply.
And if size or mass are issues at all, then you have to factor in that to get the same energy from Ar39 you're going to need something like 16x as much as you would of Ar42 - roughly 8x the half life, and only 1 beta decay per atom instead of two in rapid succession.
As for lung cancer from plutonium - it does sound nasty, but I'm uncertain it would be substantially worse than breathing radioactive argon - I suppose it would boil down to the relative length of time the two substances remained in the lungs. Argon is denser than air, but less than CO2, so it would *probably* get flushed out fairly fast, while plutonium, like other dust, would tend to be swept out and disposed of as mucous in otherwise healthy lungs (though unsurprisingly it sounds like smoking makes the cancer risks much worse).
(Score: 2) by c0lo on Wednesday May 03 2017, @01:02PM (4 children)
Not when you use it as salts, no.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by driverless on Wednesday May 03 2017, @01:20PM (3 children)
The quoted text implied solid magnesium, but you're right, it's actually magnesium ethylenediamine borohydride. Of course now we need to find out what toxic, explosive, or otherwise reactive properties magnesium ethylenediamine borohydride has...
(Score: 3, Funny) by Kromagv0 on Wednesday May 03 2017, @01:33PM (1 child)
I hear it has electrolytes so it is good for you.
T-Shirts and bumper stickers [zazzle.com] to offend someone
(Score: 1, Funny) by Anonymous Coward on Wednesday May 03 2017, @05:45PM
It's what plants crave.
(Score: 2) by Taibhsear on Wednesday May 03 2017, @03:15PM
They appear to be two components: ethylenediamine [sigmaaldrich.com] ligand and Magnesium borohydride [sigmaaldrich.com] (which is the mobile part). The safety data sheets are in the safety and documentation sections of these pages. Also remember the dosage makes the poison. These sds are for the nearly pure chemical powder.
(Score: 3, Insightful) by mcgrew on Wednesday May 03 2017, @04:32PM (2 children)
There's no way anyone knows to pack a bunch of energy in a very small space without its being dangerous.
mcgrewbooks.com mcgrew.info nooze.org
(Score: 2) by kaszz on Wednesday May 03 2017, @06:56PM (1 child)
A brick is quite dangerous, it's small and it contains 126 petajoule of energy. However one of the key factors is also the instability to degrade into a lower entropy. Which bricks generally lack.
(Score: 2, Insightful) by Anonymous Coward on Wednesday May 03 2017, @07:24PM
Well, if you put a brick in a gravity well, it'll quickly seek a lower energy state even if it has to clobber somebody in the process.
(Score: 5, Insightful) by ledow on Wednesday May 03 2017, @10:19AM (4 children)
Only if you use the pure elements.
Sodium is dangerous, sodium-chloride is not, caustic soda (NaOH) is.
Same for lithium, magnesium and all the rest of the table.
Lithium can be used for nuclear purposes, lithium carbonate is a medicine and used for setting concrete.
Stop the "scary chemicals" junk, because in an average AA alkaline battery there's potassium hydroxide. And you don't see people freaking out about that.
And you're talking about devices that are containing hundreds of thousands of joules of energy - there's no way to do that without it having some reactivity and danger in certain circumstances (in the same way that everything from paraffin to petrol is highly flammable).
Energy-dense stuff contains a lot of energy that - if released all at once - is a bomb. This isn't shocking. Whether it's fuel, batteries, gases, or a supercapacitor. If you're expecting to move a ton of metal several hundred miles using a box of energy, that box of energy is a potential bomb.
(Score: 2) by c0lo on Wednesday May 03 2017, @01:05PM
A bomb isn't shocking? Surely you jest.
(grin)
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 3, Interesting) by JoeMerchant on Wednesday May 03 2017, @01:15PM
True, though diesel is much less scary than gasoline - and has a higher energy density to boot.
🌻🌻 [google.com]
(Score: 2) by butthurt on Wednesday May 03 2017, @06:45PM (1 child)
> Sodium is dangerous, sodium-chloride is not [...] Same for lithium, magnesium [...]
By using magnesium for a significant portion of the engine block, BMW is able to reduce engine weight, reduce engine noise transmission and add strength.
[...]
Magnesium is already in widespread use where lightweight and high structural strength are needed. After seeing use in the aerospace industry, it is now being used in common items such as laptop computers, cordless power tools, and automotive components. At one time it was used to make racing wheels, hence the name “mag wheel”
-- http://www.autos.ca/auto-tech/auto-tech-bmws-30-litre-magnesiumaluminium-composite-engine-block/ [autos.ca]
Those fools! Don't they know?
(Score: 2) by Bogsnoticus on Thursday May 04 2017, @06:38AM
Mag wheels are great. Just ask Nikki Lauder.
Genius by birth. Evil by choice.
(Score: 2, Interesting) by pTamok on Wednesday May 03 2017, @10:18AM (2 children)
Lithium-Ion Battery Inventor Introduces New Technology for Fast-Charging, Noncombustible Batteries
https://news.utexas.edu/2017/02/28/goodenough-introduces-new-battery-technology [utexas.edu]
AUSTIN, Texas — A team of engineers led by 94-year-old John Goodenough, professor in the Cockrell School of Engineering at The University of Texas at Austin and co-inventor of the lithium-ion battery, has developed the first all-solid-state battery cells that could lead to safer, faster-charging, longer-lasting rechargeable batteries for handheld mobile devices, electric cars and stationary energy storage.
The researchers demonstrated that their new battery cells have at least three times as much energy density as today’s lithium-ion batteries...
Today’s lithium-ion batteries use liquid electrolytes...
...the researchers rely on glass electrolytes that enable the use of an alkali-metal anode without the formation of dendrites.
The use of an alkali-metal anode (lithium, sodium or potassium) — which isn’t possible with conventional batteries — increases the energy density of a cathode and delivers a long cycle life. In experiments, the researchers’ cells have demonstrated more than 1,200 cycles with low cell resistance.
Additionally, because the solid-glass electrolytes can operate, or have high conductivity, at -20 degrees Celsius, this type of battery in a car could perform well in subzero degree weather.
More at link.
If you do an Internet search for: goodenough sodium solid state battery you'll get a lot of coverage.
(Score: 3, Informative) by takyon on Wednesday May 03 2017, @10:50AM
http://www.pbs.org/wgbh/nova/tech/super-battery.html [pbs.org]
http://www.pbs.org/video/2365946487/ [pbs.org]
https://en.wikipedia.org/wiki/Search_for_the_Super_Battery [wikipedia.org]
http://www.sciencefriday.com/segments/booting-up-the-search-for-better-batteries/ [sciencefriday.com]
http://www.sciencefriday.com/articles/the-plastic-battery-that-doesnt-explode/ [sciencefriday.com]
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 0) by Anonymous Coward on Wednesday May 03 2017, @07:26PM
That looks good enough for me.
(Score: 0) by Anonymous Coward on Wednesday May 03 2017, @11:07AM (3 children)
The energy density of a magnesium electrolyte would solve the EV range problem, if it is double lithium's.
Not really. Until we can make small, cheap cars with 300+ mile range, the problem still needs work. This would help, no doubt, but it's not the final solution.
(Score: 2) by c0lo on Wednesday May 03 2017, @01:09PM (2 children)
OK, will dilute it some more to get to the final one. Are you pleased now?
(grin)
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by Hyperturtle on Wednesday May 03 2017, @02:45PM (1 child)
As long as we're in the business of diluting solutions in the search for a cure to energy problems, why not go for broke and promote homeopathic batteries? If we can dilute the water enough, it can run on fumes and vapor! Just like the cloud!
I wonder if there has been research done on appropriately strong enough rubber bands that can cooperate in the pressurized gas release to spin a propeller fast enough to move the car? We could add a hand crank in the front to get it wound up and then rely on nothing but potential energy to propell us into the future!
Add some solar panels and wifi (to best keep tabs on the occupant and monetize the experience) and we can have a consumer model self-driving car that needs no fuel except for the sweat and tears (sodium and water) of the frustrated passenger who only has to get out and crank it now and then, perhaps when its stuck in traffic--which creates more fuel in the process via the physical exertion. Display nothing but ads inside (perhaps a google car concept?) and we may increase the potential mileage even further via biometric feedback of the frustration levels.
Running out of gas? Maybe a few more untargeted and unskippable ads that have nothing to do with anything you would ever be interested in can be enough to get you frustrated enough to provide enough fuel to get you to your destination!
(Score: 2) by c0lo on Thursday May 04 2017, @12:46PM
Patent pending.
Patent expired [youtube.com]
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by physicsmajor on Wednesday May 03 2017, @11:16AM (4 children)
The quote from the research group is a little baffling. When they talk about energy storage vs. mass, I'm not surprised at all - the same number of atoms of sodium will weigh more than triple as much as a molar equivalent of lithium. Just look at the atomic weights. However, they then say this has volume implications. It's the same number of atoms, and that does not necessarily follow. These batteries are not a super dense bar of metal; the actual packing may vary. And, while the atomic weight is quite different, the space each takes is not. The mass will definitely matter for applications like EVs, but in consumer electronics a more proper comparison would be energy storage vs. volume - not energy storage vs. mass.
(Score: 3, Touché) by iwoloschin on Wednesday May 03 2017, @11:22AM
Mass is important too though, because at some point Apple will run out of physical thickness to shave off (you can't have negative thickness after all) and then they'll need another ridiculous claim to fame.
(Score: 2) by VLM on Wednesday May 03 2017, @12:47PM (2 children)
However, they then say this has volume implications.
Sigh. Physics Majors meddling in Chemistry Major topics....
There's a classic graph of elemental density vs atomic mass and yes its wiggly as all heck but the slope is about 5 grams/cc per 33 or so mass. So you can guess the density of lithium is less than 5 g/cc (plus or minus 50% or so) whereas a nice bar of wolfram (name just to annoy the phosphoroni pizza poster) is gonna score somewhere close to 20 grams/cc just based on atomic mass.
Meanwhile the number of electrons to F with as a battery goes up with atomic number.
So that brings up all the graphs of atomic mass vs atomic number.
When you mush it all together I don't remember the average slope (and the error bars are getting really big) but in electrochemistry it boils down to the higher the atomic number is, if you want 100 electrons (plating some metal, perhaps, or electrorefining) then the heavier those soon to be ions are gonna be and the physically larger the object.
So like lead is atomic number 82 and atomic weight 207 or so and density 12 g/cc or so vs lithium number 3 and weight 7 and 0.5g/cc
Its a simplification, like all chemistry, but 6.022e23 atoms is a mole of atoms and it weighs the atomic weight of that element.
So you want a pure lithium metal battery to push 6e23 electrons, implying 6e23 atoms of lithium change ionization state, that many is gonna weigh 3 grams, and at room temp thats about 1.5 cc which (handwave) is about 1.5 mL which is about one or two water droplets.
Meanwhile the pure lead metal plate battery in your car wants to push 6e23 electrons, implying 6e23 atoms of lead change ionization state, that many is gonna weigh 207 or so grams, and at room temp thats a fat 17 cc of lead. Thats enormously bigger than an infantry rifle bullet but only a third or so the mass of a 50 cal bullet.
So metal of a battery that can push 6e23 of electrons made of lithium resembles a fat single drop of water or if made of lead it looks like a slightly growth stunted but close enough to visually fool normies 50 cal bullet.
(Score: 2) by Immerman on Wednesday May 03 2017, @05:27PM (1 child)
As it happens, lithium atoms are actually somewhat *larger* than the heavier magnesium atoms, 182pm versus 173pm for magnesium. Include the fact that you get twice as many ionizable electrons per atom, and you might naively expect magnesium-based batteries to be only about 43% (= (173/182)³/2) the size of their lithium-based cousins (though 171% the mass)
Obviously, the discrepancies likely lie in the supporting chemistry - batteries are far more complicated than ionized metal bricks.
(Score: 2) by VLM on Wednesday May 03 2017, @06:01PM
Obviously, the discrepancies likely lie in the supporting chemistry - batteries are far more complicated than ionized metal bricks.
Oh agreed totally. Just in context of why would the chemist have a hand-wavy most of the time generally thing going on about atomic numbers vs volume of a mole (mole as in 6e23-somethings not the garden variety).
In one line without any explanation is summarizes to as atomic number goes up the mass of a mole goes up like two orders of magnitude while the density only goes up one order of magnitude so the ratio being the volume, generally speaking a mole of higher atomic number stuff will be both denser and physically larger than lighter stuff. Or the density IS increasing, but at a slower rate than the mass is increasing.
This comes up in those daydreams or sci fi movie plots about "sure atomic numbers immediately above 90 or have been radioactive, but what if there was an island of stability for super atoms with atomic number 200 or whatever" Well you can predict based on trends if there were a stable atom with a number of a couple hundred a gram-molecular-weight or whatever the cool kids call a mole today would be the size of a construction brick and it would probably have a density of like 100 g/cc which would certainly be mildly impressive. Picking up a little sugar cube of it would be like picking up a supermagnet stuck to a fridge, I can't get a grip did someone superglue this Fing thing to the lab bench?
(Score: 0) by Anonymous Coward on Wednesday May 03 2017, @11:19AM (2 children)
But more importantly, a magnesium ion has two positive charges, whereas lithium only has one.
So does Calcium, which is even more abundant and easily accessible.
(Score: 2) by fraxinus-tree on Wednesday May 03 2017, @04:53PM
..but even less mobile in solid electrolytes.
(Score: 0) by Anonymous Coward on Wednesday May 03 2017, @05:46PM
The winner in that fight isn't Ca, it Be (beryllium).
(Score: 2) by mcgrew on Wednesday May 03 2017, @04:30PM (1 child)
Is that Celsius or Kelvin?
mcgrewbooks.com mcgrew.info nooze.org
(Score: 0) by Anonymous Coward on Wednesday May 03 2017, @07:31PM
Rankines.
(Score: 3, Informative) by kaszz on Wednesday May 03 2017, @08:08PM (3 children)
The ZEBRA Na-NiCl2 battery [wikipedia.org] at Museum Autovision, Altlußheim, Germany demonstrates it's possible to use really reactive substances like Natrium. The catch is that the battery needs to be kept heated at 245 °C such that the electrolyte melts and the battery will then work. It will not loose charge while in the solid phase according to a doctor in battery chemistry.
So Lithium batteries has for now the advantage of working even at normal human temperatures.
Btw, speaking of energy carriers [eagle.ca] anyone cares to fire some Boron? ;)
(Score: 2, Informative) by pTamok on Wednesday May 03 2017, @08:45PM (2 children)
The sodium-sulfur battery was seriously investigated for use in electric vehicles. The slight downside is the need to keep the sulfur and sodium molten, so it operates at about 575 - 625 K, but there were designs that encased the battery in a thermos flask. The heat generated by the internal resistance of the battery would keep it up to temperature in normal operation. I believe it is used commercially in large fixed installations to shave peaks.
https://en.wikipedia.org/wiki/Sodium%E2%80%93sulfur_battery [wikipedia.org]
(Score: 2) by kaszz on Wednesday May 03 2017, @09:31PM (1 child)
If one can keep it hot for cheap then it should be a good deal. Questions is of course how much it costs to make?
(Score: 1) by pTamok on Thursday May 04 2017, @06:50AM
Well, it is used commercially. One further issue, pointed out in the Wikipedia article, is the formation of polysulfides, which are highly corrosive. As a battery, it works best at scale, so you are unlikely to get a sodium-sulfur battery powering your laptop, and even cars are probably marginal. Grid-scale storage of power generated earlier that can be released at times of peak demand (shaving the peak) is what it is good for, and what such batteries are currently used for, until something better comes along.