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The key word that's almost submerged in the article is molten. Like previous sodium-sulphur batteries this one relies on a molten salt electrolyte, meaning you

The key word that's almost submerged in the article is molten. Like previous sodium-sulphur batteries this one relies on a molten salt electrolyte, meaning you won't see it in your phone or laptop any time soon! However, as it's being developed with the idea of grid-scale smoothing/backup, that's much less of a problem. (The square-cube law means that as you increase the volume of your molten salt cell, the surface area grows more slowly -- and thermal losses scale with surface area, so really big cells are cheaper to maintain at operating temperature.)

koliber 4y ago
That also jumped out at me when I read it. However, later on they state that this reaction works at room temperature: > Using a simple pyrolysis process and carbon-based electrodes to improve the reactivity of sulphur and the reversibility of reactions between sulphur and sodium, the researchers’ battery has shaken off its formerly sluggish reputation, exhibiting super-high capacity and ultra-long life at room temperature. This is confusing. Can someone make some sense of this?
- dahfizz 4y ago
  > exhibiting super-high capacity and ultra-long life at room temperature. Maybe this is just bad writing? The battery (at operating temp) has high capacity, and (at room temp) can be stored for a long time? The wikipedia page indicates that it is normal to store charged molten salt batteries at room temp when not being used. https://en.wikipedia.org/wiki/Molten-salt_battery https://en.wikipedia.org/wiki/Molten-salt_battery
  - CuriousCosmic 4y ago
    I think it might literally mean "operates at room temperature" as in 25-35 degrees C. Not really sure how it works but there seems to be a distinction between high, intermediate, and room temperature for the Na-S battery's operating conditions. Quote from: https://www.tandfonline.com/doi/full/10.1080/21663831.2022.2092428 https://www.tandfonline.com/doi/full/10.1080/21663831.2022.2... 1.1. History of Na-S batteries Research on Na-S batteries originated in the 1960s, with the first research focused on High-Temperature Sodium-Sulfur (HT-Na/S) batteries, which operate around 300–350 °C. A molten Na anode (melting point=98 °C), a molten sulfur cathode (melting point = 118 °C) and ceramic β'-Al2O3 as solid electrolyte are assembled into the HT-Na/S batteries [11]. HT-Na/S batteries avoid the dendrite problem and have high electrical conductivity. However, it also has the defects of high working temperature, high risk, low energy density and high operation cost. And then, the Intermediate-Temperature Sodium-Sulfur (IMT-Na/S) batteries were innovated in the 1970s and operate between 120–300 °C. The IMT-Na/S batteries also eliminated the dendrite problem, but the electronic conductivity and the utilization of sulfur also decreased. Researchers have been intensively investigating Room-Temperature Sodium-Sulfur (RT-Na/S) batteries, which operate around 25 °C-35 °C. RT-Na/S batteries can completely convert S8 to Na2S, so they have a high theoretical energy density (1274 Wh kg−1)
- Valgrim 4y ago
  Maybe they found a way to mix it into an eutectic mixture? The article doesnt say much on the specific chemistry of the liquid salt. https://en.m.wikipedia.org/wiki/Eutectic_system https://en.m.wikipedia.org/wiki/Eutectic_system
- red_trumpet 4y ago
  The title of their article[1] is "Atomically Dispersed Dual-Site Cathode with a Record High Sulfur Mass Loading for High-Performance Room-Temperature Sodium–Sulfur Batteries". [1] https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828?utm_source=google&utm_medium=paidsearch&utm_campaign=R3MR425&utm_content=PhysSciEngineering https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828?u...
  - marcosdumay 4y ago
    Just to add, yes, that paper is about solid state batteries.
cpfohl 4y ago
I (incorrectly it seems) assumed that “molten” was just part of the manufacturing process. This take makes more sense.
bluelightning2k 4y ago
Very important detail. Thanks for highlighting. Not only does this limit practicality for phones, cars, but it limits practicality at all. Some of the larger utility scale solar-collector designs ended up failing because of the challenges of maintaining elements that involve molten salt.
Someone 4y ago
The paper’s title is “Atomically Dispersed Dual-Site Cathode with a Record High Sulfur Mass Loading for High-Performance Room-Temperature Sodium–Sulfur Batteries” (https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828?utm_source=google&utm_medium=paidsearch&utm_campaign=R3MR425&utm_content=PhysSciEngineering https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828?u...), so I guess you misread that.
deng 4y ago
No, these are room-temperature NaS batteries. They use some special electrolyte, but I have no idea how this really works. Their main drawback so far was longevity, but this battery has a capacity fade of 0.05% per cycle, which is on par at least with a poor Li-Ion battery. LiFePo4 is still superior in that regard, but the much higher capacity and hopefully lower cost (if they can be manufactured efficiently) might make up for that, hard to tell.
- ksec 4y ago
  > but this battery has a capacity fade of 0.05% per cycle, which is on par at least with a poor Li-Ion battery. 20% lost at 400 cycles. This isn't so bad if it really offers 4x the capacity. In terms of usage it will last 1600 cycles comparatively speaking. Which is still far better than Li-Ion.
  - onlyrealcuzzo 4y ago
    Can they be recycled to get back close to 100% capacity?
  - deng 4y ago
    No, Li-Ion batteries can be twice as good: "In 2003 it was reported the typical range of capacity loss in lithium-ion batteries after 500 charging and discharging cycles varied from 12.4% to 24.1%, giving an average capacity loss per cycle range of 0.025–0.048% per cycle." (https://en.wikipedia.org/wiki/Capacity_loss https://en.wikipedia.org/wiki/Capacity_loss) And that was twenty years ago, things probably have improved. I think you have a wrong impression what is meant with "a battery lasts X cycles". That does not mean that it will be at zero capacity after 'X' cycles, but usually that it is down to ~70% of the initial capacity. EDIT: Sorry, I missed the "comparatively speaking", so you mean when including the 4x capacity. You are right, of course.
    - deleted 4y ago
      [deleted]
    - nwiswell 4y ago
marcosdumay 4y ago
The paper, that red_trumpet posted down on the replies is about solid state NaS batteries.
walnutclosefarm 4y ago
The work describes a room temperature battery that uses an electrolyte of Na (sodium) in a propylene carbonate liquid carrier with electrodes made of graphene flakes with Mo and S embedded in the graphene framework. I don't know what the author of the article posted was trying to say when referring to molton Na-S, since it is not part of the battery described in the research, nor part of the manufacturing process. Probably the author did a search on Na-S for background, and not understanding how this differed, stuck it in.
passwordoops 4y ago
Nope, the PR was poorly written (maybe the Department is experimenting with chatGPT ?). Surprisingly the publication is freely available, and yes it's all room temp: https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828 https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828
- passwordoops 4y ago
  My supervisor's wife was working at a pharma company back in the 2000s. Her job was to reproduce promising publications related to any conditions they were involved in. The reproducibility rate was something like 25%, which is higher than some other estimates I've seen looking across many fields, but still.... Incentives matter and right now they're the wrong ones
- midoridensha 4y ago
  >Nope, the PR was poorly written (maybe the Department is experimenting with chatGPT ?). ChatGPT probably would have done a much better job with access to the publication. Pretty soon, these lousy science journalists are all going to be out of a job when they can't even get basic facts correct, and the real scientists don't have time to write or review PR articles themselves, so an AI will fill that role instead.
uoaei 4y ago
That is not and never was the point -- sodium is in the same column as lithium on the periodic table, but it is significantly heavier than that, so mobile applications (cars, phones) are out of scope. Sodium is promising for stationary, community- or grid-level storage.
- Tuna-Fish 4y ago
  There are many good reasons to expect sodium batteries to beat li-ion batteries in specific energy. Yes, a sodium charge carrier is ~3.2 times heavier than a lithium ion, and yes, it holds a bit less charge, but none of this has to be relevant because in a normal li-ion battery less than 1% of the total mass is active charge carriers. If you went by the simple properties of charge carriers alone, you'd expect lead-acid batteries to be at least 15 times worse than li-ion ones. However, the best lead-acid batteries are only ~8 times worse than the best li-ion batteries. Because even though the charge carriers are so much worse at doing their job, the chemistry is otherwise much more simple and easy to work with that it lets you pack a lot more charge carrier and lot less support infrastructure into the same battery. Sodium is similar, in that if you have a viable electrolyte, you can expect to utilize a lot more than 1% of the mass of your battery for usable charge carriers. This is why it's absolutely possible for molten salt batteries to have specific energies much higher than the best lithium-ion ones. As far back as 2014 there was a lab-scale prototype that beat every li-ion battery then in existence. The big downside of course is the molten part -- these are stationary batteries not due to low specific energy, but the fact that they have to be heated above ~110C to operate, and it is much more economical to make such batteries as large as possible. And in that segment, the chase is not for the highest specific energy but the lowest cost per Wh.
tremon 4y ago
you won't see it in your phone or laptop any time soon I know it's (probably) a compound and doesn't have the same properties as the individual constituents, but still I wouldn't feel entirely comfortable carrying around sodium and sulphur in my pocket all day. Maybe I'll let other people prove its safety over a few years first.
- cantaloupe 4y ago
  Is there any particular reason? Seems pretty naive to make any assumptions about the properties based on its elemental composition. Lithium is incredibly reactive and toxic in its pure form but you surely carry that around. Do you ever consume table salt, a compound of reactive sodium and toxic chlorine?
bunabhucan 4y ago
The Wikipedia article mentions two types, molten and room temperature, each with their own pros and cons. https://en.wikipedia.org/wiki/Sodium%E2%80%93sulfur_battery https://en.wikipedia.org/wiki/Sodium%E2%80%93sulfur_battery The paper mentions making the battery at 300c (oven temperature) but the text talks about "room temperature" or "RT": https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828 https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828 "...thermally treated at 300 °C for 12 h. The Mo mass loading of S@MoS2-Mo1/SGF was ≈1.2 wt.%, measured by ICP-OES. The synthesis procedure of S@MoS2/SGF was the same as S@MoS2-Mo1/SGF but the thermal treatment was extended to 24 h. To prepare the S@SGF, pure SGF was used to replace Mo1/SGF. S@Mo1/SGF was prepared by pyrolyzing the mixture of Mo1/SGF and S at 155 °C for 12 h." The only mentions of higher temperatures are for thermogravimetric analysis where they heat it to 800c and measure the amount of S as it varies with temperature.

koliber 4y ago

That also jumped out at me when I read it. However, later on they state that this reaction works at room temperature: > Using a simple pyrolysis process and carbon-based electrodes to improve the reactivity of sulphur and the reversibility of reactions between sulphur and sodium, the researchers’ battery has shaken off its formerly sluggish reputation, exhibiting super-high capacity and ultra-long life at room temperature. This is confusing. Can someone make some sense of this?

dahfizz 4y ago
> exhibiting super-high capacity and ultra-long life at room temperature. Maybe this is just bad writing? The battery (at operating temp) has high capacity, and (at room temp) can be stored for a long time? The wikipedia page indicates that it is normal to store charged molten salt batteries at room temp when not being used. https://en.wikipedia.org/wiki/Molten-salt_battery https://en.wikipedia.org/wiki/Molten-salt_battery
- CuriousCosmic 4y ago
  I think it might literally mean "operates at room temperature" as in 25-35 degrees C. Not really sure how it works but there seems to be a distinction between high, intermediate, and room temperature for the Na-S battery's operating conditions. Quote from: https://www.tandfonline.com/doi/full/10.1080/21663831.2022.2092428 https://www.tandfonline.com/doi/full/10.1080/21663831.2022.2... 1.1. History of Na-S batteries Research on Na-S batteries originated in the 1960s, with the first research focused on High-Temperature Sodium-Sulfur (HT-Na/S) batteries, which operate around 300–350 °C. A molten Na anode (melting point=98 °C), a molten sulfur cathode (melting point = 118 °C) and ceramic β'-Al2O3 as solid electrolyte are assembled into the HT-Na/S batteries [11]. HT-Na/S batteries avoid the dendrite problem and have high electrical conductivity. However, it also has the defects of high working temperature, high risk, low energy density and high operation cost. And then, the Intermediate-Temperature Sodium-Sulfur (IMT-Na/S) batteries were innovated in the 1970s and operate between 120–300 °C. The IMT-Na/S batteries also eliminated the dendrite problem, but the electronic conductivity and the utilization of sulfur also decreased. Researchers have been intensively investigating Room-Temperature Sodium-Sulfur (RT-Na/S) batteries, which operate around 25 °C-35 °C. RT-Na/S batteries can completely convert S8 to Na2S, so they have a high theoretical energy density (1274 Wh kg−1)
Valgrim 4y ago
Maybe they found a way to mix it into an eutectic mixture? The article doesnt say much on the specific chemistry of the liquid salt. https://en.m.wikipedia.org/wiki/Eutectic_system https://en.m.wikipedia.org/wiki/Eutectic_system
red_trumpet 4y ago
The title of their article[1] is "Atomically Dispersed Dual-Site Cathode with a Record High Sulfur Mass Loading for High-Performance Room-Temperature Sodium–Sulfur Batteries". [1] https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828?utm_source=google&utm_medium=paidsearch&utm_campaign=R3MR425&utm_content=PhysSciEngineering https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828?u...
- marcosdumay 4y ago
  Just to add, yes, that paper is about solid state batteries.

cpfohl 4y ago

I (incorrectly it seems) assumed that “molten” was just part of the manufacturing process. This take makes more sense.

bluelightning2k 4y ago

Very important detail. Thanks for highlighting. Not only does this limit practicality for phones, cars, but it limits practicality at all. Some of the larger utility scale solar-collector designs ended up failing because of the challenges of maintaining elements that involve molten salt.

Someone 4y ago

The paper’s title is “Atomically Dispersed Dual-Site Cathode with a Record High Sulfur Mass Loading for High-Performance Room-Temperature Sodium–Sulfur Batteries” (https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828?utm_source=google&utm_medium=paidsearch&utm_campaign=R3MR425&utm_content=PhysSciEngineering https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828?u...), so I guess you misread that.

deng 4y ago

No, these are room-temperature NaS batteries. They use some special electrolyte, but I have no idea how this really works. Their main drawback so far was longevity, but this battery has a capacity fade of 0.05% per cycle, which is on par at least with a poor Li-Ion battery. LiFePo4 is still superior in that regard, but the much higher capacity and hopefully lower cost (if they can be manufactured efficiently) might make up for that, hard to tell.

ksec 4y ago
> but this battery has a capacity fade of 0.05% per cycle, which is on par at least with a poor Li-Ion battery. 20% lost at 400 cycles. This isn't so bad if it really offers 4x the capacity. In terms of usage it will last 1600 cycles comparatively speaking. Which is still far better than Li-Ion.
- onlyrealcuzzo 4y ago
  Can they be recycled to get back close to 100% capacity?
- deng 4y ago
  No, Li-Ion batteries can be twice as good: "In 2003 it was reported the typical range of capacity loss in lithium-ion batteries after 500 charging and discharging cycles varied from 12.4% to 24.1%, giving an average capacity loss per cycle range of 0.025–0.048% per cycle." (https://en.wikipedia.org/wiki/Capacity_loss https://en.wikipedia.org/wiki/Capacity_loss) And that was twenty years ago, things probably have improved. I think you have a wrong impression what is meant with "a battery lasts X cycles". That does not mean that it will be at zero capacity after 'X' cycles, but usually that it is down to ~70% of the initial capacity. EDIT: Sorry, I missed the "comparatively speaking", so you mean when including the 4x capacity. You are right, of course.
  - deleted 4y ago
    [deleted]
  - nwiswell 4y ago

marcosdumay 4y ago

The paper, that red_trumpet posted down on the replies is about solid state NaS batteries.

walnutclosefarm 4y ago

The work describes a room temperature battery that uses an electrolyte of Na (sodium) in a propylene carbonate liquid carrier with electrodes made of graphene flakes with Mo and S embedded in the graphene framework. I don't know what the author of the article posted was trying to say when referring to molton Na-S, since it is not part of the battery described in the research, nor part of the manufacturing process. Probably the author did a search on Na-S for background, and not understanding how this differed, stuck it in.

passwordoops 4y ago

Nope, the PR was poorly written (maybe the Department is experimenting with chatGPT ?). Surprisingly the publication is freely available, and yes it's all room temp: https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828 https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828

passwordoops 4y ago
My supervisor's wife was working at a pharma company back in the 2000s. Her job was to reproduce promising publications related to any conditions they were involved in. The reproducibility rate was something like 25%, which is higher than some other estimates I've seen looking across many fields, but still.... Incentives matter and right now they're the wrong ones
midoridensha 4y ago
>Nope, the PR was poorly written (maybe the Department is experimenting with chatGPT ?). ChatGPT probably would have done a much better job with access to the publication. Pretty soon, these lousy science journalists are all going to be out of a job when they can't even get basic facts correct, and the real scientists don't have time to write or review PR articles themselves, so an AI will fill that role instead.

uoaei 4y ago

That is not and never was the point -- sodium is in the same column as lithium on the periodic table, but it is significantly heavier than that, so mobile applications (cars, phones) are out of scope. Sodium is promising for stationary, community- or grid-level storage.

Tuna-Fish 4y ago
There are many good reasons to expect sodium batteries to beat li-ion batteries in specific energy. Yes, a sodium charge carrier is ~3.2 times heavier than a lithium ion, and yes, it holds a bit less charge, but none of this has to be relevant because in a normal li-ion battery less than 1% of the total mass is active charge carriers. If you went by the simple properties of charge carriers alone, you'd expect lead-acid batteries to be at least 15 times worse than li-ion ones. However, the best lead-acid batteries are only ~8 times worse than the best li-ion batteries. Because even though the charge carriers are so much worse at doing their job, the chemistry is otherwise much more simple and easy to work with that it lets you pack a lot more charge carrier and lot less support infrastructure into the same battery. Sodium is similar, in that if you have a viable electrolyte, you can expect to utilize a lot more than 1% of the mass of your battery for usable charge carriers. This is why it's absolutely possible for molten salt batteries to have specific energies much higher than the best lithium-ion ones. As far back as 2014 there was a lab-scale prototype that beat every li-ion battery then in existence. The big downside of course is the molten part -- these are stationary batteries not due to low specific energy, but the fact that they have to be heated above ~110C to operate, and it is much more economical to make such batteries as large as possible. And in that segment, the chase is not for the highest specific energy but the lowest cost per Wh.

tremon 4y ago

you won't see it in your phone or laptop any time soon I know it's (probably) a compound and doesn't have the same properties as the individual constituents, but still I wouldn't feel entirely comfortable carrying around sodium and sulphur in my pocket all day. Maybe I'll let other people prove its safety over a few years first.

cantaloupe 4y ago
Is there any particular reason? Seems pretty naive to make any assumptions about the properties based on its elemental composition. Lithium is incredibly reactive and toxic in its pure form but you surely carry that around. Do you ever consume table salt, a compound of reactive sodium and toxic chlorine?

bunabhucan 4y ago

The Wikipedia article mentions two types, molten and room temperature, each with their own pros and cons. https://en.wikipedia.org/wiki/Sodium%E2%80%93sulfur_battery https://en.wikipedia.org/wiki/Sodium%E2%80%93sulfur_battery The paper mentions making the battery at 300c (oven temperature) but the text talks about "room temperature" or "RT": https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828 https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828 "...thermally treated at 300 °C for 12 h. The Mo mass loading of S@MoS2-Mo1/SGF was ≈1.2 wt.%, measured by ICP-OES. The synthesis procedure of S@MoS2/SGF was the same as S@MoS2-Mo1/SGF but the thermal treatment was extended to 24 h. To prepare the S@SGF, pure SGF was used to replace Mo1/SGF. S@Mo1/SGF was prepared by pyrolyzing the mixture of Mo1/SGF and S at 155 °C for 12 h." The only mentions of higher temperatures are for thermogravimetric analysis where they heat it to 800c and measure the amount of S as it varies with temperature.