11 ms·

Batteries with 50 per cent more energy with pure silicon anode

135 points by Gravityloss 9y ago

zeristor 9y ago
There is a recurrent pite patter of amazing new battery technologies, but of course the question is it can it be mass produced. Are there any good websites to gauge battery development progress as opposed to the vital, but often ephemeral research progress.
- Gravityloss 9y ago
  I was trying to create some kind of categorization prototype on google spreadsheets but it's a bit hard to squeeze out comparable metrics. Cost, Reliability, Capacity You could list cost of materials, number of cycles with 80 percent capacity left, capacity in Wh/kg. But it would still be incomplete. Maybe some "driving cycle" style standardized tests for various uses. Also manufacturing scenarios. Hard to create something non gameable.
- DennisP 9y ago
  The article addresses that: "These discoveries usually concern materials that can only be produced in a laboratory environment on a very small scale. What makes our invention so promising is that the technology for mass production of this material is already within reach due to its similarity to an existing production process for solar cells."
  - jandrese 9y ago
    I have to admit I'm a bit concerned about the amount of cost savings that can be realized by building it with the same methods as solar cells. Even with the precipitous drop in solar cell prices over the past few years they still aren't cheap.
    - DennisP 9y ago
      Sure but the question is, how much of that silicon do you need for your house vs. your car battery.
      - wernercd 9y ago
        No... the question is how easy will it be for "Solar" companies to slide into becoming "Solar & Battery" companies. Full solution - all with Silicon. If that's possible - and they can improve the cycle count... or do it cheap enough to make up for a low cycle count... or all of it - improve it, make it cheaper AND under one roof?
        hwillis 9y ago
        Current solar panels have nothing in common with this manufacturing method. It uses a machine based on obsolete amorphous thin-film silicon solar cells. The article just indicates that the technology is understood, not that solar manufacturers can produce batteries. Even if that were true, this is a release by a company... they aren't going to give away their technology for other people to use.
        wernercd 9y ago
        I never said this company would "give" away the technology... nor do they honestly have to produce it themselves. That's what licensing agreements are for. I just think that if I was a solar company that could use my equipment to produce batteries as well? That would be high on the priority list to include in packages... Companies sure do love bundling things together.
        yosyp 9y ago
        You wouldn't want to combine a solar cell and a battery in a single package; maybe in a modular system instead. After some amount of charge/discharge cycles the battery will quickly lose its capacity and utility. I suspect the operational lifespan of photovoltaics is much greater than the best batteries, and will continue to be for some time in the future.
- deleted 9y ago
  [deleted]
- hwillis 9y ago
  They steadily make their way into the mainstream. Silicon has been used in batteries for several years now, in low amounts. Usually the new "big news" comes with a significant gotcha. For silicon this has always been the cycle life. Silicon hasn't seen larger use because it expands by 400% when filled, compared to graphite's ~12% expansion. This though- this is very cool. If they've actually demonstrated 100 cycles in a pouch cell, made with reel-to-reel, that may mean that commercial cells are <5 years away. Commercial cells have 500-800 cycles in their lifetime (until their capacity falls to 80%) and are universally made on reel-to-reel machines. There are a ton of difficulties moving from a coin cell to a prismatic/pouch cell to a cylindrical cell, but I can't understate how encouraging it is that they got to 100/400 cycles. > Are there any good websites to gauge battery development progress as opposed to the vital, but often ephemeral research progress. Not that I know of, sorry.
  - csours 9y ago
    What are the critical questions you should ask about battery technology? Here are some I've thought of, please suggest others: 1. Cost of raw materials - even if the tech improves, will it still be expensive? 2. Charge/Discharge cycle count - thermal and mechanical stresses 3. Power to weight ratio; power to cost ratio 4. Manufacturability - does it require novel manufacturing techniques or can it be integrated into an existing product line 5. Round trip energy losses 6. Safety
    - hwillis 9y ago
      It helps to have some level of understanding of the chemistry. It can be hard for anyone but a legitimate chemist to sniff out the bullshit in academic papers (I've fallen prey to this before; I'm just an electrical engineer). Raw materials can be important, but only very rarely and it can also be misleading. By far most of the cost comes from the complexity and time of manufacture. That makes it tricky. For instance sulfur is far cheaper than other anode materials, but there will never be a cheap sulfur battery- it's way too complicated. It helps to know the basics[1] of battery manufacture: it's a decades old process and highly optimized. The gist is that you apply coatings to a reel of tape. If it sounds like it can't be put on a tape very easily, it will probably fail the sniff test. Solid/ceramic electrolytes and most kinds of nanotechnology fall into this category. Coating a tape is cheap, but using an electron microscope or laser on every battery is not. >2. Charge/Discharge cycle count - thermal and mechanical stresses >3. Power to weight ratio; power to cost ratio Critical. Any article, paper or press release will stress the interesting part of the battery; it's up to you to figure out how relevant it is. If the article emphasizes the current capacity, check the voltage of the chemistry. If it emphasizes the energy density, check the power density. If it emphasizes the weight, check the size. If it emphasizes safety, check everything. This is often nontrivial though. It's possible to tweak your numbers to balance things out- if you scale back the storage level you can increase cycle count, etc. If a paper has improved everything, it has a shot at being a next gen chemistry. Of course it may also be bullshit. In my experience just remembering to check the other attributes of the battery will weed out 90%+ of bad articles. Most people are honest, they're just obligated to play a certain game to keep their funding up. Unfortunately there still are folks who will publish garbage though. [1] https://www.youtube.com/watch?v=HJrNCjVS0gk https://www.youtube.com/watch?v=HJrNCjVS0gk
Gravityloss 9y ago
http://www.greencarcongress.com/2017/10/20171031-ecn.html http://www.greencarcongress.com/2017/10/20171031-ecn.html Green Car Congress provides good context. This is also a potential manufacturing revolution. But it's a hard problem because of the massive swelling of silicon during the lithiation, I think during discharge.
- vorotato 9y ago
  <joke> Oh, Solution. Phones with stretchy backs and a balloon battery. </joke>
  - juliesulti 9y ago
    You laugh, but a pouch cell as mentioned in this article is in fact a cell that is permitted to swell and shrink. That's probably why these researchers started there. As regards the article, Lithium-Silicon batteries have the potential to add much more than 50% to the charge density of Lithium-ion batteries. More like 400% in theory. But nobody has demonstrated a cheap, production-ready process for such a thing, because a charged silicon anode occupies much more space than a discharged one, and the associated mechanical stress is a severe problem. There has been an endless parade of press releases from universities and national laboratories over the past 10 years on this topic.
    - altcognito 9y ago
      In cases where space and portability aren't a concern (utility energy storage), this would be a great fit.
hwillis 9y ago
Silicon has been used in batteries for several years now in low amounts. It hasn't seen larger use because it expands by 400% when filled, compared to graphite's ~12% expansion. Most attempts to solve this have been extremely complicated; nanopatterning, nanowires, graphene coatings to literally compress the silicon metal, etc. It's one of the most promising avenues for battery tech (silicon anodes alone may be able to increase overall energy density by 2-3x), but it's been a very difficult problem to nail down. Nobody has been able to get the trifecta of performant, long-lasting and cheap. This though- this is very cool. If they've actually demonstrated 100 cycles in a pouch cell, made with reel-to-reel, that may mean that commercial cells are <5 years away. More likely 10+ years, as there are any number of things that could shut this down and the tech may not be compatible with cylindrical cells. Regardless, this is one of the most promising sounding press releases I've read in a long time. PVD anodes will be expensive (this is similar to the process to make mylar), but may be comparable to current processes, which require a long, temperamental and expensive solvent + drying process. PVD could even make this process more reliable (fewer failures) and consistent. Commercial cells have 500-800 cycles in their lifetime (until their capacity falls to 80%) and are universally made on reel-to-reel machines. If it can't be done on reel-to-real it can't be done cheaply. There are a ton of difficulties moving from a coin cell to a prismatic/pouch cell to a cylindrical cell, but I can't understate how encouraging it is that they got to 100/400 cycles. It's near unheard-of with fully silicon anodes. This is also quite promising for future development. When they say 1000-2000 mAh/g they're referring to the anode itself- only the weight of silicon, not the full battery. Silicon tops out near 4000 mAh/g, so there's a reasonable headroom there. 50% increase in overall capacity for the entire battery is fairly conservative. I presume it's because they can only apply very thin layers of anode silicon. That may mean there's a lot of room for growth though! They just have to thicken up that layer. I'm still very skeptical of their long term capacity though. The problem with anodes like this is the nanoscale features. You basically have a huge tangle of velcro: that's done to increase the surface area exposed to the electrolyte, which solves the anode expansion problem. The drawback is that when that surface area becomes restricted, and it inevitably does, the SEI affects the distribution of li ions inside the silicon, increasing damage. They do appear to have found a way around that, but it may still put a long term limit on capacity. The thicker you try to make the anode (to increase energy density), the deeper the "velcro" becomes, and the more the SEI blocks lithium. It may also make these batteries more sensitive to heat and overcurrent and over/undervoltage- anything that disturbs the SEI may cause dramatic irreversible effects. Random related fun fact: Silicon requires the use of copper rather than aluminum foils in batteries. Aluminum is a semiconductor dopant (the exact one used in your computer, in fact), and if you deposit silicon onto an aluminum foil it will form a very weak diode that causes a ton of problems. In computers an extremely thin silicon oxide film is used between aluminum wires and the transistors they connect. That layer is extremely resistive and causes a bunch of headaches, but way smaller ones than tiny diodes would!
tmaly 9y ago
Does this still need lithium?
- hwillis 9y ago
  Of course. Lithium is the third lightest element and nearly the most electronegative (ie it has a high voltage). It's the best battery material you could possibly pick! Not to mention, it's absurdly cheap and incredibly common. Lithium makes up <1% of the cost of a battery.
  - davesque 9y ago
    Is it really that common? I was under the impression that it's somewhat scarce and, furthermore, a large amount of Lithium deposits reside in regions of relative political instability: https://www.economist.com/blogs/graphicdetail/2017/06/daily-chart-12 https://www.economist.com/blogs/graphicdetail/2017/06/daily-...
    - hwillis 9y ago
      It's more common in the crust than lead, the second most common battery type, and uses ~100x less per kWh than lead acid batteries do. Lithium is very poorly mapped. The last time the USGS surveyed it was in the 50s IIRC. For instance, that article is wildly inaccurate. It lists 6.9 million tonnes in the US. A single site, 45 miles to a side, in wyoming is estimated at up to 18 million tonnes of lithium[1]. Then again America may also count as a region of relative political instability. I'll point out though that if you're gonna bring up political instability, around 20x (up to 60x in cellphones) as much cobalt is used in batteries as lithium, and virtually all of that comes from a single country: Congo. That's political instability. Lithium is a cakewalk by comparison, and fears about it are just manufactured and overblown. [1] https://oilprice.com/Energy/Energy-General/New-Wyoming-Lithium-Deposit-could-Meet-all-U.S.-Demand.html https://oilprice.com/Energy/Energy-General/New-Wyoming-Lithi...
      - drblast 9y ago
        I wish there were one of you for every article topic on here. Fascinating stuff and great explanations, thanks!
Bud 9y ago
This article, and this comment thread, both seem to be ignoring what is actually in the way of any "50% more energy" battery tech being used in consumer laptops: FAA regulations limit all such batteries to 100 watt/hrs or less. It's not Apple, it's not Samsung...they have no choice. So until we get over our stupid post-9/11 policies, it doesn't matter if Star Trek batteries magically spring into existence. The tech isn't going anywhere, other than allowing something like Apple Watch to have a little more capacity.
- rconti 9y ago
  That's fine. Laptops can keep getting more efficient. This tech can be used for cars and home storage and.. basically everything except devices like laptops that are on that 100w/h boundary. Already, laptops suffice for most flights. Then, eventually, this regulation will go away.
  - Nition 9y ago
    Have a high-capacity laptop battery for normal use and a cheap, lower capacity 100Wh one you can swap in to take on flights.
- jpm_sd 9y ago
  Those rules have nothing to do with 9/11, they are based on risk of fire due to manufacturing defects.
  - mitchty 9y ago
    That and limiting the amount of energy that could be released if there is a defect. I don't think i'd want a 1Kwh battery on a plane.
    - maxharris 9y ago
      I have never seen a laptop catch fire, on a plane or otherwise. While I have seen a few stories that report fires here and there, I really don't think this is a big issue, and I'd feel comfortable riding on a plane with lots of 1kWh batteries on it.
dzhiurgis 9y ago
Does moving on silicon reduce the need for nickel/cobalt?
- hwillis 9y ago
  No, it shouldn't. There's the anode and the cathode- anodes are invariably graphite currently, and cathodes are where the cobalt is (if there is cobalt). This is about entirely replacing the anode graphite with silicon.
googletazer 9y ago
Very thought provoking read. Speaking of batteries does anybody know what's happening with LiFePO4?
- hwillis 9y ago
  As far as I know, not too much. It's got pretty bad energy density and nowadays it's very common to just skip it entirely. It's real claim to fame is safety- it's not any cheaper despite the materials (half the cost per kg * half the capacity per kg = the same cost), and I haven't heard much about improving the performance. Meanwhile other chemistries have shown much greater improvements in safety, energy and power, and price is understood to be more about the scale than the chemistry.
  - googletazer 9y ago
    thank you

135 points by Gravityloss 9y ago

There is a recurrent pite patter of amazing new battery technologies, but of course the question is it can it be mass produced. Are there any good websites to gauge battery development progress as opposed to the vital, but often ephemeral research progress.

Gravityloss 9y ago
I was trying to create some kind of categorization prototype on google spreadsheets but it's a bit hard to squeeze out comparable metrics. Cost, Reliability, Capacity You could list cost of materials, number of cycles with 80 percent capacity left, capacity in Wh/kg. But it would still be incomplete. Maybe some "driving cycle" style standardized tests for various uses. Also manufacturing scenarios. Hard to create something non gameable.
DennisP 9y ago
The article addresses that: "These discoveries usually concern materials that can only be produced in a laboratory environment on a very small scale. What makes our invention so promising is that the technology for mass production of this material is already within reach due to its similarity to an existing production process for solar cells."
- jandrese 9y ago
  I have to admit I'm a bit concerned about the amount of cost savings that can be realized by building it with the same methods as solar cells. Even with the precipitous drop in solar cell prices over the past few years they still aren't cheap.
  - DennisP 9y ago
    Sure but the question is, how much of that silicon do you need for your house vs. your car battery.
    - wernercd 9y ago
      No... the question is how easy will it be for "Solar" companies to slide into becoming "Solar & Battery" companies. Full solution - all with Silicon. If that's possible - and they can improve the cycle count... or do it cheap enough to make up for a low cycle count... or all of it - improve it, make it cheaper AND under one roof?
      - hwillis 9y ago
        Current solar panels have nothing in common with this manufacturing method. It uses a machine based on obsolete amorphous thin-film silicon solar cells. The article just indicates that the technology is understood, not that solar manufacturers can produce batteries. Even if that were true, this is a release by a company... they aren't going to give away their technology for other people to use.
        wernercd 9y ago
        I never said this company would "give" away the technology... nor do they honestly have to produce it themselves. That's what licensing agreements are for. I just think that if I was a solar company that could use my equipment to produce batteries as well? That would be high on the priority list to include in packages... Companies sure do love bundling things together.
      - yosyp 9y ago
        You wouldn't want to combine a solar cell and a battery in a single package; maybe in a modular system instead. After some amount of charge/discharge cycles the battery will quickly lose its capacity and utility. I suspect the operational lifespan of photovoltaics is much greater than the best batteries, and will continue to be for some time in the future.
deleted 9y ago
[deleted]
hwillis 9y ago
They steadily make their way into the mainstream. Silicon has been used in batteries for several years now, in low amounts. Usually the new "big news" comes with a significant gotcha. For silicon this has always been the cycle life. Silicon hasn't seen larger use because it expands by 400% when filled, compared to graphite's ~12% expansion. This though- this is very cool. If they've actually demonstrated 100 cycles in a pouch cell, made with reel-to-reel, that may mean that commercial cells are <5 years away. Commercial cells have 500-800 cycles in their lifetime (until their capacity falls to 80%) and are universally made on reel-to-reel machines. There are a ton of difficulties moving from a coin cell to a prismatic/pouch cell to a cylindrical cell, but I can't understate how encouraging it is that they got to 100/400 cycles. > Are there any good websites to gauge battery development progress as opposed to the vital, but often ephemeral research progress. Not that I know of, sorry.
- csours 9y ago
  What are the critical questions you should ask about battery technology? Here are some I've thought of, please suggest others: 1. Cost of raw materials - even if the tech improves, will it still be expensive? 2. Charge/Discharge cycle count - thermal and mechanical stresses 3. Power to weight ratio; power to cost ratio 4. Manufacturability - does it require novel manufacturing techniques or can it be integrated into an existing product line 5. Round trip energy losses 6. Safety
  - hwillis 9y ago
    It helps to have some level of understanding of the chemistry. It can be hard for anyone but a legitimate chemist to sniff out the bullshit in academic papers (I've fallen prey to this before; I'm just an electrical engineer). Raw materials can be important, but only very rarely and it can also be misleading. By far most of the cost comes from the complexity and time of manufacture. That makes it tricky. For instance sulfur is far cheaper than other anode materials, but there will never be a cheap sulfur battery- it's way too complicated. It helps to know the basics[1] of battery manufacture: it's a decades old process and highly optimized. The gist is that you apply coatings to a reel of tape. If it sounds like it can't be put on a tape very easily, it will probably fail the sniff test. Solid/ceramic electrolytes and most kinds of nanotechnology fall into this category. Coating a tape is cheap, but using an electron microscope or laser on every battery is not. >2. Charge/Discharge cycle count - thermal and mechanical stresses >3. Power to weight ratio; power to cost ratio Critical. Any article, paper or press release will stress the interesting part of the battery; it's up to you to figure out how relevant it is. If the article emphasizes the current capacity, check the voltage of the chemistry. If it emphasizes the energy density, check the power density. If it emphasizes the weight, check the size. If it emphasizes safety, check everything. This is often nontrivial though. It's possible to tweak your numbers to balance things out- if you scale back the storage level you can increase cycle count, etc. If a paper has improved everything, it has a shot at being a next gen chemistry. Of course it may also be bullshit. In my experience just remembering to check the other attributes of the battery will weed out 90%+ of bad articles. Most people are honest, they're just obligated to play a certain game to keep their funding up. Unfortunately there still are folks who will publish garbage though. [1] https://www.youtube.com/watch?v=HJrNCjVS0gk https://www.youtube.com/watch?v=HJrNCjVS0gk

Gravityloss 9y ago

http://www.greencarcongress.com/2017/10/20171031-ecn.html http://www.greencarcongress.com/2017/10/20171031-ecn.html Green Car Congress provides good context. This is also a potential manufacturing revolution. But it's a hard problem because of the massive swelling of silicon during the lithiation, I think during discharge.

vorotato 9y ago
<joke> Oh, Solution. Phones with stretchy backs and a balloon battery. </joke>
- juliesulti 9y ago
  You laugh, but a pouch cell as mentioned in this article is in fact a cell that is permitted to swell and shrink. That's probably why these researchers started there. As regards the article, Lithium-Silicon batteries have the potential to add much more than 50% to the charge density of Lithium-ion batteries. More like 400% in theory. But nobody has demonstrated a cheap, production-ready process for such a thing, because a charged silicon anode occupies much more space than a discharged one, and the associated mechanical stress is a severe problem. There has been an endless parade of press releases from universities and national laboratories over the past 10 years on this topic.
  - altcognito 9y ago
    In cases where space and portability aren't a concern (utility energy storage), this would be a great fit.

hwillis 9y ago

Silicon has been used in batteries for several years now in low amounts. It hasn't seen larger use because it expands by 400% when filled, compared to graphite's ~12% expansion. Most attempts to solve this have been extremely complicated; nanopatterning, nanowires, graphene coatings to literally compress the silicon metal, etc. It's one of the most promising avenues for battery tech (silicon anodes alone may be able to increase overall energy density by 2-3x), but it's been a very difficult problem to nail down. Nobody has been able to get the trifecta of performant, long-lasting and cheap. This though- this is very cool. If they've actually demonstrated 100 cycles in a pouch cell, made with reel-to-reel, that may mean that commercial cells are <5 years away. More likely 10+ years, as there are any number of things that could shut this down and the tech may not be compatible with cylindrical cells. Regardless, this is one of the most promising sounding press releases I've read in a long time. PVD anodes will be expensive (this is similar to the process to make mylar), but may be comparable to current processes, which require a long, temperamental and expensive solvent + drying process. PVD could even make this process more reliable (fewer failures) and consistent. Commercial cells have 500-800 cycles in their lifetime (until their capacity falls to 80%) and are universally made on reel-to-reel machines. If it can't be done on reel-to-real it can't be done cheaply. There are a ton of difficulties moving from a coin cell to a prismatic/pouch cell to a cylindrical cell, but I can't understate how encouraging it is that they got to 100/400 cycles. It's near unheard-of with fully silicon anodes. This is also quite promising for future development. When they say 1000-2000 mAh/g they're referring to the anode itself- only the weight of silicon, not the full battery. Silicon tops out near 4000 mAh/g, so there's a reasonable headroom there. 50% increase in overall capacity for the entire battery is fairly conservative. I presume it's because they can only apply very thin layers of anode silicon. That may mean there's a lot of room for growth though! They just have to thicken up that layer. I'm still very skeptical of their long term capacity though. The problem with anodes like this is the nanoscale features. You basically have a huge tangle of velcro: that's done to increase the surface area exposed to the electrolyte, which solves the anode expansion problem. The drawback is that when that surface area becomes restricted, and it inevitably does, the SEI affects the distribution of li ions inside the silicon, increasing damage. They do appear to have found a way around that, but it may still put a long term limit on capacity. The thicker you try to make the anode (to increase energy density), the deeper the "velcro" becomes, and the more the SEI blocks lithium. It may also make these batteries more sensitive to heat and overcurrent and over/undervoltage- anything that disturbs the SEI may cause dramatic irreversible effects. Random related fun fact: Silicon requires the use of copper rather than aluminum foils in batteries. Aluminum is a semiconductor dopant (the exact one used in your computer, in fact), and if you deposit silicon onto an aluminum foil it will form a very weak diode that causes a ton of problems. In computers an extremely thin silicon oxide film is used between aluminum wires and the transistors they connect. That layer is extremely resistive and causes a bunch of headaches, but way smaller ones than tiny diodes would!

tmaly 9y ago

Does this still need lithium?

hwillis 9y ago
Of course. Lithium is the third lightest element and nearly the most electronegative (ie it has a high voltage). It's the best battery material you could possibly pick! Not to mention, it's absurdly cheap and incredibly common. Lithium makes up <1% of the cost of a battery.
- davesque 9y ago
  Is it really that common? I was under the impression that it's somewhat scarce and, furthermore, a large amount of Lithium deposits reside in regions of relative political instability: https://www.economist.com/blogs/graphicdetail/2017/06/daily-chart-12 https://www.economist.com/blogs/graphicdetail/2017/06/daily-...
  - hwillis 9y ago
    It's more common in the crust than lead, the second most common battery type, and uses ~100x less per kWh than lead acid batteries do. Lithium is very poorly mapped. The last time the USGS surveyed it was in the 50s IIRC. For instance, that article is wildly inaccurate. It lists 6.9 million tonnes in the US. A single site, 45 miles to a side, in wyoming is estimated at up to 18 million tonnes of lithium[1]. Then again America may also count as a region of relative political instability. I'll point out though that if you're gonna bring up political instability, around 20x (up to 60x in cellphones) as much cobalt is used in batteries as lithium, and virtually all of that comes from a single country: Congo. That's political instability. Lithium is a cakewalk by comparison, and fears about it are just manufactured and overblown. [1] https://oilprice.com/Energy/Energy-General/New-Wyoming-Lithium-Deposit-could-Meet-all-U.S.-Demand.html https://oilprice.com/Energy/Energy-General/New-Wyoming-Lithi...
    - drblast 9y ago
      I wish there were one of you for every article topic on here. Fascinating stuff and great explanations, thanks!

Bud 9y ago

This article, and this comment thread, both seem to be ignoring what is actually in the way of any "50% more energy" battery tech being used in consumer laptops: FAA regulations limit all such batteries to 100 watt/hrs or less. It's not Apple, it's not Samsung...they have no choice. So until we get over our stupid post-9/11 policies, it doesn't matter if Star Trek batteries magically spring into existence. The tech isn't going anywhere, other than allowing something like Apple Watch to have a little more capacity.

rconti 9y ago
That's fine. Laptops can keep getting more efficient. This tech can be used for cars and home storage and.. basically everything except devices like laptops that are on that 100w/h boundary. Already, laptops suffice for most flights. Then, eventually, this regulation will go away.
- Nition 9y ago
  Have a high-capacity laptop battery for normal use and a cheap, lower capacity 100Wh one you can swap in to take on flights.
jpm_sd 9y ago
Those rules have nothing to do with 9/11, they are based on risk of fire due to manufacturing defects.
- mitchty 9y ago
  That and limiting the amount of energy that could be released if there is a defect. I don't think i'd want a 1Kwh battery on a plane.
  - maxharris 9y ago
    I have never seen a laptop catch fire, on a plane or otherwise. While I have seen a few stories that report fires here and there, I really don't think this is a big issue, and I'd feel comfortable riding on a plane with lots of 1kWh batteries on it.

dzhiurgis 9y ago

Does moving on silicon reduce the need for nickel/cobalt?

hwillis 9y ago
No, it shouldn't. There's the anode and the cathode- anodes are invariably graphite currently, and cathodes are where the cobalt is (if there is cobalt). This is about entirely replacing the anode graphite with silicon.

googletazer 9y ago

Very thought provoking read. Speaking of batteries does anybody know what's happening with LiFePO4?

hwillis 9y ago
As far as I know, not too much. It's got pretty bad energy density and nowadays it's very common to just skip it entirely. It's real claim to fame is safety- it's not any cheaper despite the materials (half the cost per kg * half the capacity per kg = the same cost), and I haven't heard much about improving the performance. Meanwhile other chemistries have shown much greater improvements in safety, energy and power, and price is understood to be more about the scale than the chemistry.
- googletazer 9y ago
  thank you