9 ms·

Extra salty sodium battery performs on par with lithium

180 points by bornelsewhere 6y ago

wccrawford 6y ago
It keeps saying "some lithium-ion batteries". >a comparable energy capacity and cycling ability to some lithium-ion batteries Is that just covering their asses, or does this only perform as well as the worst-performing lithium-ion batteries?
- Reason077 6y ago
  Performing on par with the "worst" lithium-ion batteries would still be a great success if sodium-ion is cheaper to manufacture. They would still perform much better than lead-acid, Ni-MH, etc. There's a huge demand for cheaper batteries.
  - skohan 6y ago
    Especially in cases where size/weight is not critically important. This could be a huge deal for something like a home solar setup where batteries can make up a significant portion of the cost.
    - slfnflctd 6y ago
      I've been waiting for competition in this space to heat up for about full decade now. Around the start of the 2010s I was doing a ton of research, and it seemed like a big win was just around the corner... somehow it seems farther away now. I really hope something - anything - makes it out of the lab at a market-busting price point soon, it might actually give me a chance to restart some projects that have been collecting dust on the shelf for way too long.
      - choeger 6y ago
        The thing is that li ion batteries bare these 10 years ahead. So to be competitive now, a battery chemistry bmust be either 10times cheaper (rough estimate) or fill in a niche application (high density, very stable). A battery that is just five times as cheap will never catch up to the learnings of li ion manufacturing.
        chrispeel 6y ago
        "I think there is a world market for maybe five computers." I.e. it seems a bit bold to say A battery that is just five times as cheap will never catch up to the learnings of li ion manufacturing.
        skohan 6y ago
        But that calculation is affected by the commodity prices of lithium as well. If demand for batteries increases (i.e. if most people started driving electric cars) then a technology could go from 5 to 10 times as cheap very quickly
    - wlesieutre 6y ago
      Also a huge deal for grid-scale applications. We've seen Tesla do that with lithium ion batteries for grid stability and energy price arbitrage, but if it were cheap and easy to produce batteries at massive scale without needing relatively rare elements like lithium, maybe we'd have big enough batteries to run the whole grid overnight off of solar.
      - csours 6y ago
        I was curious as to relative abundance: https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth%27s_crust https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth... Sodium is number 6 on the list, while Lithium is way down in the middle (above lead, below cobalt). Also, you can literally scoop sodium out of the ocean, so extraction will never be a problem over any reasonable human timescale.
        AaronM 6y ago
        I was curious about how much salt was in the ocean. There is approximately 50 quintillion kilograms of salt in the ocean, which is nearly the mass of the moon From this website https://scripps.ucsd.edu/news/what-makes-ocean-salty-and-how-much-salt-ocean https://scripps.ucsd.edu/news/what-makes-ocean-salty-and-how...
        danw1979 6y ago
        I’m no quantity surveyor, but that sounds like someone placed the decimal point blindfolded in that calculation. A quick google says the mass of just the water on Earth is 0.02% of total mass and the mass of the moon is 1.2% of Earth’s. Someone please point out my mistake.
        frandroid 6y ago
        "Thanks for pointing out this mistake. Since we currently have no quantity surveyor, we would like to hand over control of the Planetary Quantity Survey repository to you. This is an open source project with no pay which requires 80 hours of thankless work a week. Good luck!"
  - pvaldes 6y ago
    > would still be a great success if sodium-ion is cheaper to manufacture Either if would be slightly more expensive, the environmental and logistic consequences (not depending on a few places in a few countries to mine it, not needing to import the raw materials from another continent) would be also a noticeable factor.
- hmwhy 6y ago
  To be fair, that doesn't appear to be a quote and the last few words of the sentence you quoted is important: > ... offering a comparable energy capacity and cycling ability to some lithium-ion batteries already on the market. Having said that, it seems they do claim in the paper that the performance of their "battery" (really, they only tested a single cathode composition) is "competitive to the commercial LiFePO4-graphite" base on extrapolation of their lab results "to practical large format cells". I feel funny about that sort of extrapolation in an engineering context, but I'm not an electrochemist and also not a chemical engineer, and I have only skimmed through the abstract, introductions, and conclusions of the paper; so take this comment with a grain of salt. Edit: typo. Also, I'm not out to trash the work in case my comment comes across as being harsh—marketing aside (which is, sadly, pretty common in high-impact journals), it does seem like a step forward.
  - wccrawford 6y ago
    The article used the word "some" multiple times, which is why I began to wonder about it. Weasel words are kind of a trigger for me.
    - hmwhy 6y ago
      On a personal level, I tend to agree with you because of some traumatic experiences with collaborators in the past. But I think there is at least one valid reason for using imprecise terms in scientific journalism: it makes the content more accessible.
markdown 6y ago
Someone tell me how this amazing discovery won't work in practice.
- rzzzt 6y ago
  ...in mice! Sorry, wrong thread.
- ShorsHammer 6y ago
  There's a universe of uses for batteries. Really depends on what you want it for. For the average person using consumer products they are usually concerned with energy density and cost. Apart from electric cars most companies don't really care about no. of cycles, especially for phones.
  - dgoldstein0 6y ago
    ... but don't we charge our phones every day? 1000 cycles feels like a minimum for that - would be required for a phone to last 3 years.
    - viktorko 6y ago
      In my experience phone batteries start to deteriorate after about two year.
    - ShorsHammer 6y ago
      Mobile phones are the poster child of planned obsolescence as insinuated in my comment.
  - rfrey 6y ago
    Surely grid applications doing daily balancing care about cycles.
    - deleted 6y ago
      [deleted]
    - 6y ago
Altheasy 6y ago
One of the problems with them in their current form, however, is that while this is going on inactive sodium crystals tend to build up on the surface of the negatively-charged electrode, the cathode, which winds up killing the battery. Additionally, sodium-ion batteries don't hold as much energy as their lithium-ion counterparts.
- barrkel 6y ago
  > Song and his team believe they may have come up with a solution to these shortcomings. (Not sure what you're getting at here.)
- deleted 6y ago
  [deleted]
- recrof 6y ago
  You better read the whole article.
- gamblor956 6y ago
  The whole point of this press release is that they believe they've solved that particular problem.
smt88 6y ago
Recent context on sodium batteries: https://www.chemistryworld.com/features/a-battery-technology-worth-its-salt/3010966.article https://www.chemistryworld.com/features/a-battery-technology...
Ice_cream_suit 6y ago
Controlling Surface Phase Transition and Chemical Reactivity of O3-Layered Metal Oxide Cathodes for High-Performance Na-Ion Batteries Junhua Song, Kuan Wang, Jianming Zheng, Mark H. Engelhard, Biwei Xiao, Enyuan Hu, Zihua Zhu, Chongmin Wang, Manling Sui, Yuehe Lin, David Reed, Vincent L. Sprenkle, Pengfei Yan, and Xiaolin Li ACS Energy Lett. 2020, 5, XXX, 1718–1725 Publication Date:April 28, 2020 https://doi.org/10.1021/acsenergylett.0c00700 https://doi.org/10.1021/acsenergylett.0c00700 "Abstract: O3-layered metal oxides are promising cathode materials for high-energy Na-ion batteries (SIBs); however, they suffer from fast capacity fade. Here, we develop a high-performance O3-NaNi0.68Mn0.22Co0.10O2 cathode for SIBs toward practical applications by suppressing the formation of a rock salt layer at the cathode surface with an advanced electrolyte. The cathode can deliver a high specific capacity of ∼196 mAh g–1 and demonstrates >80% capacity retention over 1000 cycles. NaNi0.68Mn0.22Co0.10O2–hard carbon full-cells with practical loading (>2.5 mAh cm–2) and lean electrolyte (∼40 μL) demonstrate ∼82% capacity retention after 450 cycles. A 60 mAh single-layer pouch cell has also been fabricated and demonstrated stable performance. This work represents a significant leap in SIB development and brings new insights to the development of advanced layered metal oxide cathodes for alkaline-ion batteries."
- lstodd 6y ago
  82% capacity retention after 450 cycles is nothing to write home about. Besides those are lab tests. Show a thousand cycles of a hundred cells at various temperatures and vibration loads and there will be something to talk about.
JoeAltmaier 6y ago
Gotta be dead-heavy? Sodium is atomic weight 22, while Lithum is 7. Three times as heavy? Or is the electrolyte too small a fraction to matter much.
- ysleepy 6y ago
  There is very little actual lithium in li-ion batteries. This will not be a problem.
  - JoeAltmaier 6y ago
    Hm. There's a lot of lead, in a lead-acid battery. Must be very different.
    - OnlyOneCannolo 6y ago
      Even if it wasn't ... If the energy density and mass density of a sodium battery are between lead-acid and lithium-ion, then an equally capable battery would weigh somewhere in-between.
  - mehrdadn 6y ago
    For those wondering: 0.6 grams of lithium out of 45 grams for an 18650 battery, or about 1.3% by weight.
    - JoeAltmaier 6y ago
      Thanks! I just looked that up and was going to post. Beat me to it! So it is very different - a li-ion battery anode is a tiny part of the battery. A lead-acid battery, its a much larger component.
  - Ididntdothis 6y ago
    Makes we wonder why li-ion AA batteries weigh so much less than Nimh rechargeable. What’s the difference?
jasoneckert 6y ago
It's nice to see this progress - it's definitely been a focus for people for a long time. I remember one of my chemistry profs in the 1990s telling us how Sodium ion batteries could eclipse Lithium ion batteries once we figure out the practicality to make it work.
baybal2 6y ago
TIP: The shortage of lithium is nowhere near as "catastrophic" as stockmarket people believe. The shortage of cobalt is a by far bigger problem. It's basically 80% about Congo, and what happens there. 50% to 80% of global supply can evaporate overnight if something is happening there.
- Sevaris 6y ago
  Wouldn't a sodium-ion battery be much more environmentally friendly to produce? It seems like there's value in sustainability that makes this attractive over lithium-based batteries.
  - baybal2 6y ago
    Maybe, sodium is after all spent by megatonnes in inorganic chemistry
  - bufferoverflow 6y ago
    Only if the energy density is not important for your application. There are such applications, but they are a minority. Smartphones, laptops, car batteries all want to be both light and small.
    - Sevaris 6y ago
      Is it a minority? What about batteries tied to energy grids like the Tesla battery farm in Australia? Wouldn't that be a potential use case which would be useful across the globe?
    - myself248 6y ago
      Yeah, but if all the grid storage and powerwall production could go sodium, that would free up lithium for the places it's needed. The same argument could be made for nickel-iron batteries, though. They're heavy and bulky, but they last literally forever, and their source materials are ludicrously abundant. Why don't we see nickel-iron grid-scale storage? I'd love to know.
mehrdadn 6y ago
Sort of off-topic, but why is sodium more abundant than lithium?
- Tade0 6y ago
  Not a chemist, but apparently even in its stable isotopes the nucleus is barely holding together.
- smolder 6y ago
  The stellar processes that result in stable lithium are rare, like supernovas.[1] Another factor in its rarity as a material is that while it's present in a lot of things, it's not present in quantities for economical recovery. 1. https://www.forbes.com/sites/startswithabang/2019/11/14/this-is-why-three-of-the-lightest-elements-are-so-cosmically-rare/ https://www.forbes.com/sites/startswithabang/2019/11/14/this...
  - mehrdadn 6y ago
    Ahh, thanks! So if I understand correctly, it's because its stable isotopes can only be produced in high quantities through fission rather than fusion (otherwise they get destroyed in the same processes).
- Valgrim 6y ago
  Lithium, beryllium and boron are rare because although they are produced by nuclear fusion, they are destroyed by other fusion reactions in the stars. This property is used to distinguish low mass stars and brown dwarfs. https://en.wikipedia.org/wiki/Lithium_burning https://en.wikipedia.org/wiki/Lithium_burning https://en.wikipedia.org/wiki/Cosmological_lithium_problem#Observed_abundance_of_lithium https://en.wikipedia.org/wiki/Cosmological_lithium_problem#O...
fnord77 6y ago
how is this possible with Li having a higher electronegativity than Na?
- JoeAltmaier 6y ago
  Use more Na?
peter_d_sherman 6y ago
>"One of the problems with them in their current form, however [...] inactive sodium crystals tend to build up on the surface of the negatively-charged electrode [...] which winds up killing the battery." [...] "Experimenting with the design of sodium-ion batteries led the team to produce a version with a cathode made of layered metal oxide and a liquid electrolyte with a higher concentration of sodium ions. In testing, the team found that this led to a much smoother interaction between the electrolyte and the cathode, enabling the continuous movement of the sodium ions and avoiding the troublesome buildup of inactive crystals on the cathode surface. The upshot of that was battery offering capacity similar to some lithium-ion batteries and with an uninterrupted generation of electricity, maintaining 80 percent of its charge after 1,000 cycles."
hinkley 6y ago
During the dotcom era someone tried to build Flow batteries (although I don't think the term had been coined yet), and if memory serves they were sodium chemistry. There's a hint on the wikipedia page that someone may be trying it again, but I'm having trouble following the citations to figure out who.

180 points by bornelsewhere 6y ago

It keeps saying "some lithium-ion batteries". >a comparable energy capacity and cycling ability to some lithium-ion batteries Is that just covering their asses, or does this only perform as well as the worst-performing lithium-ion batteries?

Reason077 6y ago
Performing on par with the "worst" lithium-ion batteries would still be a great success if sodium-ion is cheaper to manufacture. They would still perform much better than lead-acid, Ni-MH, etc. There's a huge demand for cheaper batteries.
- skohan 6y ago
  Especially in cases where size/weight is not critically important. This could be a huge deal for something like a home solar setup where batteries can make up a significant portion of the cost.
  - slfnflctd 6y ago
    I've been waiting for competition in this space to heat up for about full decade now. Around the start of the 2010s I was doing a ton of research, and it seemed like a big win was just around the corner... somehow it seems farther away now. I really hope something - anything - makes it out of the lab at a market-busting price point soon, it might actually give me a chance to restart some projects that have been collecting dust on the shelf for way too long.
    - choeger 6y ago
      The thing is that li ion batteries bare these 10 years ahead. So to be competitive now, a battery chemistry bmust be either 10times cheaper (rough estimate) or fill in a niche application (high density, very stable). A battery that is just five times as cheap will never catch up to the learnings of li ion manufacturing.
      - chrispeel 6y ago
        "I think there is a world market for maybe five computers." I.e. it seems a bit bold to say A battery that is just five times as cheap will never catch up to the learnings of li ion manufacturing.
      - skohan 6y ago
        But that calculation is affected by the commodity prices of lithium as well. If demand for batteries increases (i.e. if most people started driving electric cars) then a technology could go from 5 to 10 times as cheap very quickly
  - wlesieutre 6y ago
    Also a huge deal for grid-scale applications. We've seen Tesla do that with lithium ion batteries for grid stability and energy price arbitrage, but if it were cheap and easy to produce batteries at massive scale without needing relatively rare elements like lithium, maybe we'd have big enough batteries to run the whole grid overnight off of solar.
    - csours 6y ago
      I was curious as to relative abundance: https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth%27s_crust https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth... Sodium is number 6 on the list, while Lithium is way down in the middle (above lead, below cobalt). Also, you can literally scoop sodium out of the ocean, so extraction will never be a problem over any reasonable human timescale.
      - AaronM 6y ago
        I was curious about how much salt was in the ocean. There is approximately 50 quintillion kilograms of salt in the ocean, which is nearly the mass of the moon From this website https://scripps.ucsd.edu/news/what-makes-ocean-salty-and-how-much-salt-ocean https://scripps.ucsd.edu/news/what-makes-ocean-salty-and-how...
        danw1979 6y ago
        I’m no quantity surveyor, but that sounds like someone placed the decimal point blindfolded in that calculation. A quick google says the mass of just the water on Earth is 0.02% of total mass and the mass of the moon is 1.2% of Earth’s. Someone please point out my mistake.
        frandroid 6y ago
        "Thanks for pointing out this mistake. Since we currently have no quantity surveyor, we would like to hand over control of the Planetary Quantity Survey repository to you. This is an open source project with no pay which requires 80 hours of thankless work a week. Good luck!"
- pvaldes 6y ago
  > would still be a great success if sodium-ion is cheaper to manufacture Either if would be slightly more expensive, the environmental and logistic consequences (not depending on a few places in a few countries to mine it, not needing to import the raw materials from another continent) would be also a noticeable factor.
hmwhy 6y ago
To be fair, that doesn't appear to be a quote and the last few words of the sentence you quoted is important: > ... offering a comparable energy capacity and cycling ability to some lithium-ion batteries already on the market. Having said that, it seems they do claim in the paper that the performance of their "battery" (really, they only tested a single cathode composition) is "competitive to the commercial LiFePO4-graphite" base on extrapolation of their lab results "to practical large format cells". I feel funny about that sort of extrapolation in an engineering context, but I'm not an electrochemist and also not a chemical engineer, and I have only skimmed through the abstract, introductions, and conclusions of the paper; so take this comment with a grain of salt. Edit: typo. Also, I'm not out to trash the work in case my comment comes across as being harsh—marketing aside (which is, sadly, pretty common in high-impact journals), it does seem like a step forward.
- wccrawford 6y ago
  The article used the word "some" multiple times, which is why I began to wonder about it. Weasel words are kind of a trigger for me.
  - hmwhy 6y ago
    On a personal level, I tend to agree with you because of some traumatic experiences with collaborators in the past. But I think there is at least one valid reason for using imprecise terms in scientific journalism: it makes the content more accessible.

markdown 6y ago

Someone tell me how this amazing discovery won't work in practice.

rzzzt 6y ago
...in mice! Sorry, wrong thread.
ShorsHammer 6y ago
There's a universe of uses for batteries. Really depends on what you want it for. For the average person using consumer products they are usually concerned with energy density and cost. Apart from electric cars most companies don't really care about no. of cycles, especially for phones.
- dgoldstein0 6y ago
  ... but don't we charge our phones every day? 1000 cycles feels like a minimum for that - would be required for a phone to last 3 years.
  - viktorko 6y ago
    In my experience phone batteries start to deteriorate after about two year.
  - ShorsHammer 6y ago
    Mobile phones are the poster child of planned obsolescence as insinuated in my comment.
- rfrey 6y ago
  Surely grid applications doing daily balancing care about cycles.
  - deleted 6y ago
    [deleted]
  - 6y ago

Altheasy 6y ago

One of the problems with them in their current form, however, is that while this is going on inactive sodium crystals tend to build up on the surface of the negatively-charged electrode, the cathode, which winds up killing the battery. Additionally, sodium-ion batteries don't hold as much energy as their lithium-ion counterparts.

barrkel 6y ago
> Song and his team believe they may have come up with a solution to these shortcomings. (Not sure what you're getting at here.)
deleted 6y ago
[deleted]
recrof 6y ago
You better read the whole article.
gamblor956 6y ago
The whole point of this press release is that they believe they've solved that particular problem.

smt88 6y ago

Recent context on sodium batteries: https://www.chemistryworld.com/features/a-battery-technology-worth-its-salt/3010966.article https://www.chemistryworld.com/features/a-battery-technology...

Ice_cream_suit 6y ago

Controlling Surface Phase Transition and Chemical Reactivity of O3-Layered Metal Oxide Cathodes for High-Performance Na-Ion Batteries Junhua Song, Kuan Wang, Jianming Zheng, Mark H. Engelhard, Biwei Xiao, Enyuan Hu, Zihua Zhu, Chongmin Wang, Manling Sui, Yuehe Lin, David Reed, Vincent L. Sprenkle, Pengfei Yan, and Xiaolin Li ACS Energy Lett. 2020, 5, XXX, 1718–1725 Publication Date:April 28, 2020 https://doi.org/10.1021/acsenergylett.0c00700 https://doi.org/10.1021/acsenergylett.0c00700 "Abstract: O3-layered metal oxides are promising cathode materials for high-energy Na-ion batteries (SIBs); however, they suffer from fast capacity fade. Here, we develop a high-performance O3-NaNi0.68Mn0.22Co0.10O2 cathode for SIBs toward practical applications by suppressing the formation of a rock salt layer at the cathode surface with an advanced electrolyte. The cathode can deliver a high specific capacity of ∼196 mAh g–1 and demonstrates >80% capacity retention over 1000 cycles. NaNi0.68Mn0.22Co0.10O2–hard carbon full-cells with practical loading (>2.5 mAh cm–2) and lean electrolyte (∼40 μL) demonstrate ∼82% capacity retention after 450 cycles. A 60 mAh single-layer pouch cell has also been fabricated and demonstrated stable performance. This work represents a significant leap in SIB development and brings new insights to the development of advanced layered metal oxide cathodes for alkaline-ion batteries."

lstodd 6y ago
82% capacity retention after 450 cycles is nothing to write home about. Besides those are lab tests. Show a thousand cycles of a hundred cells at various temperatures and vibration loads and there will be something to talk about.

JoeAltmaier 6y ago

Gotta be dead-heavy? Sodium is atomic weight 22, while Lithum is 7. Three times as heavy? Or is the electrolyte too small a fraction to matter much.

ysleepy 6y ago
There is very little actual lithium in li-ion batteries. This will not be a problem.
- JoeAltmaier 6y ago
  Hm. There's a lot of lead, in a lead-acid battery. Must be very different.
  - OnlyOneCannolo 6y ago
    Even if it wasn't ... If the energy density and mass density of a sodium battery are between lead-acid and lithium-ion, then an equally capable battery would weigh somewhere in-between.
- mehrdadn 6y ago
  For those wondering: 0.6 grams of lithium out of 45 grams for an 18650 battery, or about 1.3% by weight.
  - JoeAltmaier 6y ago
    Thanks! I just looked that up and was going to post. Beat me to it! So it is very different - a li-ion battery anode is a tiny part of the battery. A lead-acid battery, its a much larger component.
- Ididntdothis 6y ago
  Makes we wonder why li-ion AA batteries weigh so much less than Nimh rechargeable. What’s the difference?

jasoneckert 6y ago

It's nice to see this progress - it's definitely been a focus for people for a long time. I remember one of my chemistry profs in the 1990s telling us how Sodium ion batteries could eclipse Lithium ion batteries once we figure out the practicality to make it work.

baybal2 6y ago

TIP: The shortage of lithium is nowhere near as "catastrophic" as stockmarket people believe. The shortage of cobalt is a by far bigger problem. It's basically 80% about Congo, and what happens there. 50% to 80% of global supply can evaporate overnight if something is happening there.

Sevaris 6y ago
Wouldn't a sodium-ion battery be much more environmentally friendly to produce? It seems like there's value in sustainability that makes this attractive over lithium-based batteries.
- baybal2 6y ago
  Maybe, sodium is after all spent by megatonnes in inorganic chemistry
- bufferoverflow 6y ago
  Only if the energy density is not important for your application. There are such applications, but they are a minority. Smartphones, laptops, car batteries all want to be both light and small.
  - Sevaris 6y ago
    Is it a minority? What about batteries tied to energy grids like the Tesla battery farm in Australia? Wouldn't that be a potential use case which would be useful across the globe?
  - myself248 6y ago
    Yeah, but if all the grid storage and powerwall production could go sodium, that would free up lithium for the places it's needed. The same argument could be made for nickel-iron batteries, though. They're heavy and bulky, but they last literally forever, and their source materials are ludicrously abundant. Why don't we see nickel-iron grid-scale storage? I'd love to know.

mehrdadn 6y ago

Sort of off-topic, but why is sodium more abundant than lithium?

Tade0 6y ago
Not a chemist, but apparently even in its stable isotopes the nucleus is barely holding together.
smolder 6y ago
The stellar processes that result in stable lithium are rare, like supernovas.[1] Another factor in its rarity as a material is that while it's present in a lot of things, it's not present in quantities for economical recovery. 1. https://www.forbes.com/sites/startswithabang/2019/11/14/this-is-why-three-of-the-lightest-elements-are-so-cosmically-rare/ https://www.forbes.com/sites/startswithabang/2019/11/14/this...
- mehrdadn 6y ago
  Ahh, thanks! So if I understand correctly, it's because its stable isotopes can only be produced in high quantities through fission rather than fusion (otherwise they get destroyed in the same processes).
Valgrim 6y ago
Lithium, beryllium and boron are rare because although they are produced by nuclear fusion, they are destroyed by other fusion reactions in the stars. This property is used to distinguish low mass stars and brown dwarfs. https://en.wikipedia.org/wiki/Lithium_burning https://en.wikipedia.org/wiki/Lithium_burning https://en.wikipedia.org/wiki/Cosmological_lithium_problem#Observed_abundance_of_lithium https://en.wikipedia.org/wiki/Cosmological_lithium_problem#O...

fnord77 6y ago

how is this possible with Li having a higher electronegativity than Na?

JoeAltmaier 6y ago
Use more Na?

peter_d_sherman 6y ago

>"One of the problems with them in their current form, however [...] inactive sodium crystals tend to build up on the surface of the negatively-charged electrode [...] which winds up killing the battery." [...] "Experimenting with the design of sodium-ion batteries led the team to produce a version with a cathode made of layered metal oxide and a liquid electrolyte with a higher concentration of sodium ions. In testing, the team found that this led to a much smoother interaction between the electrolyte and the cathode, enabling the continuous movement of the sodium ions and avoiding the troublesome buildup of inactive crystals on the cathode surface. The upshot of that was battery offering capacity similar to some lithium-ion batteries and with an uninterrupted generation of electricity, maintaining 80 percent of its charge after 1,000 cycles."

hinkley 6y ago

During the dotcom era someone tried to build Flow batteries (although I don't think the term had been coined yet), and if memory serves they were sodium chemistry. There's a hint on the wikipedia page that someone may be trying it again, but I'm having trouble following the citations to figure out who.