[HN Gopher] Na-S Battery: Low-cost with four times the capacity ...
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       Na-S Battery: Low-cost with four times the capacity of lithium
        
       Author : giuliomagnifico
       Score  : 262 points
       Date   : 2022-12-15 12:07 UTC (10 hours ago)
        
 (HTM) web link (www.sydney.edu.au)
 (TXT) w3m dump (www.sydney.edu.au)
        
       | MonkeyClub wrote:
       | Seems to be a legitimate advance in a long-disregarded battery
       | tech, I'd be very happy if this ends up reducing lithium mining.
        
         | danuker wrote:
         | Indeed, and it might also drive down prices. Sodium and sulphur
         | are much more abundant than Lithium (1150x and 260x
         | respectively).
         | 
         | https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth...
        
           | flavius29663 wrote:
           | This wiki page has a surprising graph https://en.wikipedia.or
           | g/wiki/Abundance_of_elements_in_Earth...
           | 
           | The "rare earths" are actually just as common as Si. It just
           | shows we won't be running out of them anytime soon, it's just
           | a matter of finding ways to extract them.
        
             | pfdietz wrote:
             | Si is the symbol for silicon, which is the second most
             | abundant element in the Earth's crust (after oxygen.) The
             | REEs are certainly not as abundant as that. Si is 270,000
             | ppm; cerium is 60 ppm.
        
               | flavius29663 wrote:
               | You're right, I'm dumb, the graph is 0 at 10^6 Si. So
               | rare earths are 1 million times more rare than Si. It's
               | similar to copper and Nickel though
        
             | squarefoot wrote:
             | Although, by looking at the places where they are more
             | abundant, I wouldn't be too optimist, at least with the
             | current geopolitical climate.
             | 
             | https://www.statista.com/statistics/277268/rare-earth-
             | reserv...
        
             | ojbyrne wrote:
             | I'm not sure how you're interpreting that graph, because Si
             | (Silicon) and Na are orders of magnitude more common than
             | the rare earths. You might have missed that it's a
             | logarithmic scale.
        
           | usrusr wrote:
           | Is the material that ends up in the cell a significant part
           | of the cost? If steel was free, ICE cars could be _dozens of
           | dollars_ cheaper than they are. I guess material costs are a
           | much bigger factor in batteries, but in many other products
           | is so low that  "much bigger" could still be tiny.
        
           | GekkePrutser wrote:
           | Does the 1150 take into account all the oceans full of NaCl?
           | It sounds a little low.
        
           | ddulaney wrote:
           | Sodium and sulphur are very cheap and easy to get, but not
           | because of this.
           | 
           | Sulphur is a byproduct of lots of different industrial
           | processes, usually oil refining.
           | 
           | Sodium is most commonly extracted from seawater.
           | 
           | Frequency of elements in Earth's crust is a pretty poor
           | approximation for how easy they are to mine.
        
         | supportlocal4h wrote:
         | Imagine a desalination process funded in part by producing
         | battery-grade sodium.
         | 
         | All you practical people who wait until there is real world
         | manufacturing promise are missing out on the pleasure of wild
         | imagination.
        
           | jfengel wrote:
           | Imagination is great, but there's a blurry line between
           | "imagine a thing and make it happen" and "tell happy stories
           | instead of working".
           | 
           | One belongs in science journals; the other belongs in
           | Astounding Stories. Both have their place, and there's even
           | some overlap, but it's no surprise that grumpiness occurs
           | when the conversation crosses that blurry line too far (in
           | either direction).
        
           | marcus_holmes wrote:
           | "we're all doomed"
           | 
           | "wait, there's a new battery tech that could solve some of
           | the long-standing problems with moving to a clean-energy
           | abundant civilisation, and yesterday they achieved fusion
           | ignition for the first time"
           | 
           | "bah, these are all rubbish and will never make any
           | difference, we're still all doomed"
        
         | hcarvalhoalves wrote:
         | Yes. The electrification movement isn't any "green" if you take
         | into account the impact of current battery technology.
         | 
         | PS: the impact of battery _technology_ - I'm not only talking
         | about mining but the entire cycle: usable life, reverse
         | logistics, disposal and recycling, dealing w / water and soil
         | contamination.
        
           | adrr wrote:
           | Lithium on earth is in salt form. Most coming from dry salt
           | beds in South America. Big US project is to extract it from
           | the Salton sea. Fracking is much worse and contaminates water
           | tables not to mention all the methane releases that cause
           | global warming.
        
             | kragen wrote:
             | you're out of date, half of current lithium production is
             | hard rock mining of spodumene in australia
        
           | ZeroGravitas wrote:
           | So its not fossil fuel funded climate change denial, it's
           | actually about the ethics of lithium mining?
        
           | raverbashing wrote:
           | Ah yes.
           | 
           | Digging for coal or gas or oil, fracking, etc: just fine
           | 
           | Mining for (significant less amount of) lithium or other
           | metals: "oh look they're ruining the environment"
           | 
           | As most discussions go, they're heavily biased towards the
           | status quo
        
             | hcarvalhoalves wrote:
             | You have not only the impact of mining but also the problem
             | of reverse logistics for correct disposal and recycling of
             | those toxic batteries that don't even last long. Batteries
             | contaminate soil and water in a way that's much harder to
             | control if it start piling up everywhere. And today's world
             | can't even solve the disposal of plastic.
        
               | galangalalgol wrote:
               | With intelligent charging practices (which often come at
               | the expense of stored energy) and temperature control,
               | modern lithium cells asymptote to ~20% capacity loss and
               | stay there for, well at least since the model S came out,
               | still counting. Or that was the case a couple years ago
               | when I looked into it. The difference in the battery life
               | in a leaf vs a tesla is qualitative not quantitative. The
               | motivation to make phone batteries last longer wasn't
               | there at first until it provided negative press, now
               | intelligent charging is fairly common in phones. Thermal
               | management is harder.
        
               | nine_k wrote:
               | Lithium batteries are a great source of lithium, and
               | bigger of them, like laptop batteries, largely get
               | recycled even now, AFAICT. Lithium + iron chemistries in
               | particular avoid seriously toxic components.
               | 
               | Both lithium and plastics are far less nasty than, say,
               | ash from a coal-burning plant, with its sulfur, mercury,
               | and radioactive stuff. Retiring these is a higher
               | priority thing, IMO, than improving lithium mining
               | cleanliness (though an improvement is always welcome).
        
             | fnordpiglet wrote:
             | Brine extraction of lithium leaves some waste but largely
             | uses solar power to operate and isn't particularly
             | invasive. Mining Spodumene is as bad as any other mining,
             | and open pit mining is common. There's some other
             | techniques that use large amounts of highly concentrated
             | acid. But it's a really hard case to make that the oil
             | economy is somehow a better environmental story for sure.
        
             | willnonya wrote:
             | Both of those can be bad at once you know...
             | 
             | A lithium mine is much more devastating to the environment
             | than an oil well or franking. That doesn't mean either of
             | these are really good options despite what either side
             | wants to pretend.
        
               | KyeRussell wrote:
               | This sort of both-sidesing doesn't further the
               | conversation at all. Do you really think the person
               | you're replying to doesn't know that mining Lithium isn't
               | without its environmental costs?
               | 
               | The person you're replying to quite correctly notes that
               | mining Lithium is an improvement over extracting coal,
               | oil, and gas. The term "green" is so nebulous snd ill-
               | defined that it's not worth talking about.
               | 
               | The best thing humanity can do for the earth is clearly
               | to remove ourselves from it. Anything less than that is
               | compromise. Sure. But sitting here saying "there's no
               | such thing as ethical consumption" doesn't really get us
               | anywhere.
        
               | MonkeyClub wrote:
               | Precisely; it's not big oil propaganda to understand the
               | environmental effects of lithium mining, just as it's not
               | lithium propaganda to acknowledge the equivalent
               | consequences of the oil industry on the environment.
               | 
               | But if we get to have a way to move at super-human speeds
               | (ie > 5 km/h walking and > 30 km/h running), cheaply and
               | without environmentally detrimental consequences, that'd
               | be great :)
               | 
               | (Fellow cyclists, I know, cycling is an excellent
               | solution for single-person small- and mid-range movement.
               | I'm thinking here of mass transportation and goods
               | transportation, where it'd be hard to use cycle-powered
               | lorries across continents.)
        
               | scythe wrote:
               | >A lithium mine is much more devastating to the
               | environment than an oil well or franking.
               | 
               | This isn't true at all. Lithium is mined in much smaller
               | quantities and in fewer places. In some cases (Cornwall,
               | e.g.), it can be obtained as a byproduct of geothermal
               | energy. It can also be recycled. By contrast, the
               | Wikipedia list of environmental disasters has an entire
               | _section_ devoted to oil:
               | 
               | https://en.wikipedia.org/wiki/List_of_environmental_disas
               | ter...
        
               | nine_k wrote:
               | What makes a lithium mine so bad? Oil wells prone to
               | generate lots of saltwater, too.
        
               | 1ris wrote:
               | Both can be bad, and both are bad.
               | 
               | But it looks like a lot of people assume they are just as
               | bad without any quantitate or qualitative assessment.
               | 
               | Lithium mining is way less bad than oil extraction in
               | both dimensions. If that lithium can offset oil
               | consumption it looks particular good.
        
               | jl6 wrote:
               | No doubt that mining lithium has negative impacts, but
               | those negative impacts feel localized in a way that can
               | in principle be mitigated and cleaned up, and though bad
               | for local communities, it doesn't pose existential risk.
               | This is in stark contrast to the fossil fuel cycle which
               | distributes pollution globally into the atmosphere, and
               | will be tremendously difficult to undo.
        
               | defrost wrote:
               | Untouched National Parks don't bounce back to pre mine
               | status so that's a Yes to "in principle" but a No to "in
               | practice".
               | 
               |  _Lithium exploration drilling near Litchfield National
               | Park raises sustainability questions_ [1]
               | 
               | > University of Queensland professor of conservation
               | science James Watson says that mining associated with
               | renewable energy could cover about 50 million square
               | kilometres of the Earth's surface by 2050.
               | 
               | > His prediction is startling.
               | 
               | > "About 10 per cent will be in national parks and
               | protected areas, another 7 or so per cent will be in
               | areas that have been identified as critical biodiversity
               | areas to sustain species and stop extinction, and a
               | further 15 per cent or so will be in our last remaining
               | wilderness on the planet," he said.
               | 
               | I've spent a few decades in mineral exploration, in
               | geophysics and in mapping global mineral and energy
               | resources.
               | 
               | We have some real issues to sort out going forward with
               | respect to resource extraction and the rights of
               | indigenous people and wilderness.
               | 
               | [1] https://www.abc.net.au/news/2022-12-13/lithium-found-
               | near-li...
        
               | jupp0r wrote:
               | What percentage of national parks will be affected by
               | climate change? I see your point but if we have two bad
               | options and one is absolutely worse than the other,
               | making them look equivalent because they have some
               | environmental impact is not helpful to protecting as much
               | if the environment as possible.
        
               | defrost wrote:
               | A surprisingly high percentage in National Parks globally
               | (ie. many different jurisdictions) that are also (or
               | adjacent to) indigenous lands with various treaties and
               | contracts.
               | 
               | eg: The US has one ~$64 billion copper resource (leased
               | to Anglo - Australians) in native lands [1] which is an
               | as yet unresolved and sizeable can of worms, and that's
               | barely the start of the list (although it is the largest
               | global pending copper project).
               | 
               | There's a nice GIS directory of such things that we (here
               | in W.Australia) compiled a decade ago (along with
               | automation to run it forward) that's now a bit paywalled
               | [2]
               | 
               | [1] https://en.wikipedia.org/wiki/Resolution_Copper
               | 
               | [2] https://www.spglobal.com/marketintelligence/en/campai
               | gns/met...
        
       | megaman821 wrote:
       | These scientific advances in batteries are cool, but I don't take
       | them as a specific indicator of what is coming. It is a numbers
       | game, if there are 1000 scientific advances maybe 1 or 2 will
       | survive the gauntlet and make it into manufacturing in the next
       | 10 years.
       | 
       | It seems reasonable that there will be battery options that cost
       | 50% as much and others that have 2x greater energy density in the
       | near future. That seems great to me. Batteries will be viable and
       | economical across most storage needs expect for aviation,
       | shipping and seasonal grid storage.
        
         | SV_BubbleTime wrote:
         | Same. If you follow articles like this you'll be constantly
         | wondering what happened to "x".
         | 
         | ("Graphene can do everything except get out of the lab")
        
         | RGamma wrote:
         | Specifically for grid storage I'd like to see more attention
         | given to gravity batteries [0], the compressed liquid type.
         | 
         | Recently saw a video (in German, [1]) in which there was back-
         | of-the-envelope calculation that a gravity battery built by
         | hydraulically raising a cylindrical landmass with 1km diameter
         | by 500 meters stores about 2TWh (recent yearly gross
         | electricity consumption of Germany is 560TWh).
         | 
         | It's such a simple concept! Also, they are looking for
         | investors: https://heindl-energy.com/
         | 
         | [0] https://en.wikipedia.org/wiki/Gravity_battery
         | 
         | [1] https://youtube.com/watch?v=pnomwGCBNAE
        
           | amalcon wrote:
           | Pumped-storage hydro (the cheapest and generally most
           | practical gravity battery) is currently responsible for
           | almost all grid-scale energy storage worldwide. I don't think
           | it's fair to say it's not getting attention.
           | 
           | What's not getting attention is the use of solids for this.
           | The main reasons are that you'd like to re-use most of the
           | infrastructure of the hydroelectric dam you wanted anyway,
           | and that liquids make for simpler engineering in these cases.
        
             | toss1 wrote:
             | What is interesting about a quick look at the Heindl Energy
             | solution is that it looks like basically pumped hydro.
             | 
             | The difference is that the water is sitting in a large
             | cylindrical space underground with a large (minimum 100m /
             | 300ft diameter) rock piston sitting on top of the water.
             | 
             | Eliminates the need for mountainous terrain with a high
             | lake-like geometry to pump the water up out of the gravity
             | well -- they can build this in the flatlands
        
           | AndrewDucker wrote:
           | That is an obscenely large cylinder. And a large height to
           | raise it!
        
           | acc_297 wrote:
           | There are simpler technologies that already exist on this
           | principle pumped hydro being the main one this proposal seems
           | like overkill to have so much storage in a single location
        
             | RGamma wrote:
             | Well of course you can divide up the mass and build several
             | smaller installations.
             | 
             | I was merely hinting at the fact that pumped hydro storage
             | can be made more compact and flexible by compressing the
             | liquid with a piston.
        
       | willnonya wrote:
       | While I welcome this advancement it still seems like a solution
       | to the wrong solution for another problem.
        
         | SamBam wrote:
         | Very unclear what you mean. Large-scale, cheap, safe, and
         | environmental energy storage is a huge issue that is nowhere
         | near solved yet, so more solutions are absolutely a good thing.
        
       | waynesonfire wrote:
       | capacity is but one of many characteristics of a successfully
       | battery technology. it's important to consider just about every
       | possible factor,
       | 
       | capacity, power density, charge and discharge rate, lifespan /
       | shelf life, safety, voltage range, temperature ranges while
       | charging, discharging, cycle count.
       | 
       | And, also, the performance of these attributes under various
       | temperature profiles.
       | 
       | This list is far from exhaustive, I'm not a battery expert but
       | just something I came up with in a few minutes of thought. So,
       | gtfo with your capacity claim. Every few months a battery break-
       | through article comes out. I've become de-sensitize to this type
       | of news.
        
         | simmerup wrote:
         | What is your comment actually adding?
        
       | benreesman wrote:
       | I'm a layman as concerns batteries, but I'm old enough, just like
       | photovoltaics, for the prevailing view to be: this is at the
       | asymptote, it's not getting any better.
       | 
       | I'm glad some people decided not to listen to that bollocks.
        
         | Aardwolf wrote:
         | For solar panels I agree, there's a hard limit of how much
         | energy per area the sun itself gives, and how much efficiency
         | you can physically get out of that.
         | 
         | For batteries: biological creatures store more energy more
         | densily, yet safely, so there's still headroom.
        
           | ilyt wrote:
           | > For batteries: biological creatures store more energy more
           | densily, yet safely, so there's still headroom.
           | 
           | Conversion losses are bigger tho
        
             | stickfigure wrote:
             | I'm not looking forward to cleaning my house battery's
             | litter box.
        
           | TheIronYuppie wrote:
           | I think the general thinking is that cost is going to be the
           | determining factor for PV. It it gets to be cheaper than
           | paper, for ex, you could just put it everywhere.
           | 
           | But there are still lots of wins - we're only in the low 20s
           | for efficiency and mostly catching visible light. There's
           | also environmental, long life, etc ways to improve as well.
        
             | fps-hero wrote:
             | Solar is by far the cheapest form of energy by a
             | significant margin. It is already at the point where it
             | makes sense to put it everywhere, and have concentrated
             | large scale generation.
             | 
             | For solar to win, we need to solve energy storage, or
             | perhaps the energy distribution problem. There is no amount
             | of solar which will give you power 24 hours in a day in a
             | single location.
             | 
             | Energy storage is the best short term solution. If we can
             | capture peak solar generation and move that energy to the
             | peak demand period, we can have a serious discussion about
             | moving away from coal for baseload generation. It won't be
             | needed during the day, and the demand periods covered by
             | storage.
             | 
             | However, for solar to really win, we need to think bigger
             | with our energy distribution networks. Think of a global
             | scale distribution network, like an internet for
             | electricity.
             | 
             | If you can send an IP packet from your computer across the
             | world, why not energy?
             | 
             | With a sufficiently large interconnected global scale
             | network of renewable generators, energy storage becomes
             | less important. We don't need gas pipelines, we need
             | longitudinal and latitudinal HV distribution networks.
        
               | danans wrote:
               | > If you can send an IP packet from your computer across
               | the world, why not energy?
               | 
               | This has already begun in the form of the new
               | transmission line under the North Sea between England and
               | Norway, which will be used to store wind power from the
               | UK in pumped hydro facilities in Norway. [1]
               | 
               | But sending electricity at grid transmission levels
               | across major ocean distances may not pencil out
               | economically.
               | 
               | Politics also comes into play. In the US for example, the
               | Texas grid won't even attach to the rest of the national
               | grid.
               | 
               | 1. https://en.m.wikipedia.org/wiki/North_Sea_Link
        
               | cesarb wrote:
               | > For solar to win, [...] If we can capture peak solar
               | generation and move that energy to the peak demand
               | period, we can have a serious discussion about moving
               | away from coal for baseload generation.
               | 
               | Why is it always solar vs coal? The generation mix
               | depends on your network, but AFAIK, the world is already
               | moving away from coal towards natural gas; and solar is
               | often complemented by wind.
        
           | Gasp0de wrote:
           | But afaik, solar panels currently convert only 20% of the
           | energy to electricity, can you explain why this is close to
           | the theoretically or practically possible maximum?
        
             | benreesman wrote:
             | I'm the wrong kind of an engineer to have a cogent thought
             | / argument about that.
             | 
             | My remark was more of an anecdote that these things are
             | getting better in spite of a great deal of pessimism about
             | them over my lifetime.
        
               | [deleted]
        
             | Aardwolf wrote:
             | There's a theoretical limit of 55% for unconcentrated, 85%
             | for concentrated sunlight. I'm not sure about the exact
             | thermodynamical reasons for those numbers.
             | 
             | But claims of "1000x better" can physically never be true,
             | unlike for batteries (e.g. antimatter, no matter how
             | impractical, has millions times more energy density)
        
           | perlgeek wrote:
           | Solar panels still have some dimensions along which they
           | could improve, for example:
           | 
           | * efficiency in low-light situations
           | 
           | * efficiency when parts of the panel are covered
           | 
           | * cost
           | 
           | I guess the inverters could also be improved...
        
       | gumboza wrote:
       | Time will tell. All new battery technologies solve one problem
       | but create two more.
       | 
       | Edit: I'm not necessarily talking about technology problems.
       | There are geopolitical and environmental problems too :)
        
         | qwertox wrote:
         | https://www.energy-storage.news/basf-takes-sodium-sulfur-bat...
        
       | sylware wrote:
       | How do you process them once they run out of reasonably efficient
       | cycles?
       | 
       | Reconditioning facilities? wastes? etc?
        
         | Tagbert wrote:
         | Considering the main ingredients are sodium and sulfur,
         | recycling should not be a major problem. Those are commonly
         | used elements and not particularly toxic.
         | 
         | This question is always asked about EV batteries. Their
         | recycling is something that is being developed but is still in
         | prototype phase. Actual production scale recycling is not
         | feasible yet because the number of retired EV batteries is too
         | small to be efficiently recycled. That will eventually change
         | but since EV batteries are generally lasting for a decade or
         | more, it will take several years before we start seeing
         | significant numbers needing to be recycled. I would expect that
         | the same story would apply to these batteries if they are
         | deployed.
        
           | sylware wrote:
           | "recycling should not be a major problem", well, this is
           | where more details would be more than welcome.
        
       | microjim wrote:
       | Would love to hear from domain experts here. Reading the article
       | one finds that they only created very small cathodes rather than
       | anything close to a 'consumer sized' battery.
       | 
       | (The full text of the paper is available for free at
       | https://onlinelibrary.wiley.com/doi/10.1002/adma.202206828)
        
         | scythe wrote:
         | I'm not a battery expert, but I have looked into Na-S before.
         | While it's a great rhetorical bludgeon in arguments about what
         | batteries can do in theory -- we'll never run out of sodium or
         | sulfur -- actual costs of Na-S installations are consistently
         | much higher than lithium or other battery types. For example,
         | this review cites a present system cost of over $400/kWh:
         | 
         | https://www.mdpi.com/1996-1073/13/13/3307
         | 
         | A new scientific development can be cool, but it won't directly
         | reduce costs, since it's not actually an industrial process. A
         | lower operating temperature might simplify construction. But
         | all that remains to be seen.
         | 
         | EDIT: if you read the original paper in TFA you will find that
         | molybdenum, an extremely rare metal, is key to the cathode,
         | though only at 1.2% by weight. Interpretation unclear.
        
         | jpm_sd wrote:
         | It's just more science by press release. Wake me up when
         | there's a real manufacturing process developed.
        
         | app4soft wrote:
         | > _Reading the article one finds that they only created very
         | small cathodes rather than anything close to a 'consumer sized'
         | battery_
         | 
         | There are few articles on 'consumer sized' _18650_ sodium-ion
         | (Na-S, Na-ion) battery (aka NIB):
         | 
         | October 2019: _Developing O3 type layered oxide cathode and its
         | application in 18650 commercial type Na-ion batteries_ [0]
         | 
         | May 2022: _First 18650-format Na-ion cells aging investigation:
         | A degradation mechanism study_ [1]
         | 
         | August 2022: _Remaining useful life prediction for 18650
         | sodium-ion batteries based on incremental capacity analysis_
         | [2]
         | 
         | [0]
         | https://www.researchgate.net/publication/336562138_Developin...
         | 
         | [1]
         | https://www.researchgate.net/publication/359078973_First_186...
         | 
         | [2]
         | https://www.researchgate.net/publication/362754837_Remaining...
        
       | Tade0 wrote:
       | I wonder how does it stack up against non-flow zinc-bromide
       | batteries, which apparently are already being produced and are
       | aiming for the stationary storage market:
       | 
       | https://www.pv-magazine-australia.com/2022/09/30/gelion-unve...
       | 
       | The 2MWh/yr plant is very small, but reportedly it's a repurposed
       | lead-acid facility because the production process is similar
       | enough.
        
       | m3kw9 wrote:
       | With batteries is that there are way more factors than just
       | capacity. You need thermal run way, cold/hot weather perf, heat
       | generated, charge time, numb cycles before capacity is 80%,
       | weight power ratio, scalability and cost
        
         | thehappypm wrote:
         | Some applications are easier than others. Grid storage, for
         | example, can be in climate controlled warehouses, do optimal
         | charging cycles to maximize longevity, don't care about weight,
         | etc.
        
       | dreamcompiler wrote:
       | Sodium-sulfur batteries are already in use for grid storage [0]
       | [1]. They're large and they have to be kept hot, so they won't
       | work for mobile applications. This article seems to be describing
       | one that works at room temperature.
       | 
       | [0] https://www.energy-storage.news/uae-integrates-648mwh-of-
       | sod...
       | 
       | [1] https://www.bestmag.co.uk/worlds-largest-sodium-sulphur-
       | ess-...
        
       | jojobas wrote:
       | Li-S is already 2.5x the energy density of TNT.
       | 
       | Before you say "petrol", petrol is typically not carried in the
       | form petrol/oxygen fizz and its energy density is therefore zero.
        
         | foxhill wrote:
         | likely because the logistics of handling and utilising an
         | energy source that can materialise the entirety of its stored
         | energy instantly has some safety concerns.
         | 
         | requiring air is not a limitation, it's a feature.
        
           | jojobas wrote:
           | I'm saying I'd rather not be near a 100kW-h Na-S battery.
           | Current Li-Po batteries require quite some shielding at tiny
           | a fraction of the energy density if you don't want to burn.
        
         | gruturo wrote:
         | TNT has actually pretty low energy density - lower than
         | chocolate chip cookies if I remember correctly. It's only used
         | because of its ability to deliver it all in one go - something
         | cookies lack. Energy density alone is a fairly inadequate
         | metric to decide how dangerous some material is, and what
         | precautions to take handling and transporting it.
        
           | jojobas wrote:
           | Just as petrol, cookies have energy density of zero until
           | mixed with oxygen. Just like TNT, or more like black powder,
           | batteries have all components required to yield energy in one
           | enclosure, which is why there are battery explosion videos
           | and no cookie explosion videos.
        
       | Robotbeat wrote:
       | They don't mention the actual specific energy of the completed
       | cells in Wh/kg. Also, "four times of WHAT?" They need to compare
       | like-to-like, which would mean comparing to an equivalent Li-S
       | cells.
       | 
       | Li-S cells usually have much higher specific energy than regular
       | lithium ion. I doubt these cells are better, considering sodium
       | is heavier than lithium.
       | 
       | The highest lithium ion cells you can get now are Amperium cells
       | at 390Wh/kg, plus the metal anode Licerion cells at over
       | 400Wh/kg. That's not counting lithium sulfur which can get to
       | 650Wh/kg (but are still stuck in the lab).
        
         | mikeyouse wrote:
         | They tested the drawdown at 1V with cells over 1,000 mah/gram
         | so >1,000wh/kg if that voltage is their operating voltage.
        
         | deng wrote:
         | They say the charge capacity is 1017 mAh/g. That is about four
         | times the value of a typical (good!) Li-Ion battery.
        
           | dev_tty01 wrote:
           | Not useful without the cell voltage. Need both to figure out
           | the energy storage. Anyone?
        
             | mikeyouse wrote:
             | Cell degradation was tested at 1V - so conveniently right
             | around 1,000wh/kg.
        
           | bjarneh wrote:
           | Isn't that quite close to the magic number which makes
           | electric planes a viable option? 1 kW = 1 kg; Musk said
           | something about that in a podcast I think...
        
             | termain wrote:
             | That's specific power, not specific energy. Do you mean 1
             | kW*r/kg?
        
               | bjarneh wrote:
               | Yes of course, I meant to say 1 kW*h = 1 kg; but I'm not
               | certain if I remember correctly now; I could be off by a
               | factor of 10 I guess. It was either 1 kg battery weight =
               | 1 kW*h, or perhaps he said 10 kW*h had to be contained in
               | a 1 kg battery to allow all types of air travel.
               | 
               | I think the 100 kW*h Tesla batteries found in the Model
               | S/X weigh around 750 kg; so I guess electric air travel
               | is still difficult unless a battery breakthrough happens;
               | at least in terms of weight.
        
           | danw1979 wrote:
           | ... assuming the cell voltage is the same ?
           | 
           | A quick google suggests Na-S cells at high temperatures are
           | ~2.1V nominal (as opposed to 3.2V for LFP), but I lack the
           | physics chops to parse the paper in the article to validate
           | this. Anyway this sounds like a tiny experimental cell and
           | for real world applications you'd want to see the Wh/kg for a
           | fully packaged product.
        
             | deng wrote:
             | > for real world applications you'd want to see the Wh/kg
             | for a fully packaged product
             | 
             | Oh, absolutely, there's still a lot of stuff that could
             | prohibit this technology from ever becoming an actual
             | product. AFAICS, they also don't say anything about
             | dependence an ambient temperature, for instance. It might
             | be that this thing disintegrates as soon as it's freezing.
             | Or, actually the most likely: that it's simply not possible
             | to build this thing at scale with reasonable cost.
        
       | mikeytown2 wrote:
       | Let me know when I can buy 30kwh worth of energy storage so I can
       | compare it to Lifepo4 costs [1]
       | 
       | [1] $10,500 https://signaturesolar.com/eg4-ll-lithium-batteries-
       | kit-48v-...
        
         | aidenn0 wrote:
         | LiFePO4 batteries are really magical; mostly made of easy-to-
         | find materials, good density, long lifetime, hard to make
         | explode.
        
       | kennydude wrote:
       | This would be great also if, during damage situations they are
       | less harmful than Lithium Ion batteries (which cause very hot,
       | self sustaining fires for hours and hours!)
        
         | galangalalgol wrote:
         | I would think any dry cell would have this as a problem? If you
         | stuff a kWh into a box and get it back out without adding
         | anything, there is a kWh in that box, and I think all these
         | sorts of reactions proceed faster at higher temperatures, so
         | wouldn't runaway always be a possibility?
        
         | ajross wrote:
         | This is all FUD, and I wish people would stop repeating it.
         | Battery fires in vehicles (which I assume is what you're
         | talking about) are _objectively safer than gasoline fires_.
         | They just are.
         | 
         | It's true though that they have to be fought differently,
         | because they can't be extinguished by flushing the fuel away as
         | you can for liquid fires. So the "hours and hours" bit is sorta
         | true, I guess. But having to keep people away from a battery
         | fire for a while while you hose it down is an annoyance, not a
         | safety concern.
         | 
         | In any case the battery under discussion is a molten
         | electrolyte thing intended for grid storage, not vehicles.
        
           | ilyt wrote:
           | > This is all FUD, and I wish people would stop repeating it.
           | Battery fires in vehicles (which I assume is what you're
           | talking about) are objectively safer than gasoline fires.
           | They just are.
           | 
           | They just happen way more often, petrol tank is smaller
           | tucked in usually somewhere in the back of the car, VS
           | battery cell where just puncture can start a fire where
           | gasoline can "just" leak without catching fire. Althought I
           | imagine chance for that grows a lot with old cars, once they
           | start to rot from corrosion
        
             | cesarb wrote:
             | > petrol tank is smaller tucked in usually somewhere in the
             | back of the car
             | 
             | I think most car fires are not from the fuel tank leaking,
             | but instead from a short somewhere in its electric system,
             | or from a leaking hose spraying flammable liquid (fuel,
             | oil, etc) onto a hot surface (like the motor). Compared
             | with an ICE vehicle, an EV should have less hoses with
             | flammable fluids, but more parts on its electric system.
        
             | ajross wrote:
             | > They just happen way more often
             | 
             | I don't think that's true either? Obviously the FUD angle
             | means that it Makes Big News when EVs burn. But gasoline
             | cars burn all the time.
             | 
             | Look, if there's evidence for battery safety issues then
             | let's discuss it. But there isn't. There are millions of
             | EVs on the roads now. Can we even name one accident where
             | someone was injured by an EV fire? It's just not there.
             | This is wrong. What you're repeating is wrong.
        
           | gamblor956 wrote:
           | Today I learned that a fire that cannot be put out with water
           | or by smothering it, and which must be left to burn for hours
           | on end, and which produces a variety of gases more toxic than
           | those resulting from gasoline combustion, is safer than a
           | gasoline fire that burns out in a few minutes.
           | 
           | Mind blown.
        
       | ncann wrote:
       | Sorry, I can't resist the urge to repost this classic comment on
       | a thread about new battery technology:
       | 
       | Dear battery technology claimant,
       | 
       | Thank you for your submission of proposed new revolutionary
       | battery technology. Your new technology claims to be superior to
       | existing lithium-ion technology and is just around the corner
       | from taking over the world. Unfortunately your technology will
       | likely fail, because:
       | 
       | [ ] it is impractical to manufacture at scale.
       | 
       | [ ] it will be too expensive for users.
       | 
       | [ ] it suffers from too few recharge cycles.
       | 
       | [ ] it is incapable of delivering current at sufficient levels.
       | 
       | [ ] it lacks thermal stability at low or high temperatures.
       | 
       | [ ] it lacks the energy density to make it sufficiently portable.
       | 
       | [ ] it has too short of a lifetime.
       | 
       | [ ] its charge rate is too slow.
       | 
       | [ ] its materials are too toxic.
       | 
       | [ ] it is too likely to catch fire or explode.
       | 
       | [ ] it is too minimal of a step forward for anybody to care.
       | 
       | [ ] this was already done 20 years ago and didn't work then.
       | 
       | [ ] by this time it ships li-ion advances will match it.
       | 
       | [ ] your claims are lies.
        
         | jasonwatkinspdx wrote:
         | I find it tiresome empty snark.
         | 
         | Better batteries are a really big deal. Is every promising
         | technology gonna work out? Of course not. But there's valid
         | reasons to be interested and excited. I _like_ that these
         | stories appear on HN so I can keep a rough understanding of how
         | research is progressing. And usually there 's some comments
         | here from people who know the field a lot better. But to find
         | those gems I have to scroll past a whole crowd of people
         | posting this self congratulatory snark.
        
           | pessimizer wrote:
           | > I have to scroll past a whole crowd of people posting this
           | self congratulatory snark.
           | 
           | Has this comment ever been posted more than once in a thread?
           | 
           | edit: and I honestly can't understand what is self-
           | congratulatory about a list of issues created by somebody who
           | is obviously interested in batteries, and has seen a lot of
           | press releases with the same flaws. It gives laymen a
           | sensible list to check the newest claim against.
        
             | jasonwatkinspdx wrote:
             | It's not as bad in this thread, it's more that every single
             | thread in this topic area has this sort of snark, if not
             | the exact text template, as the number one or two comment.
             | 
             | Sure it's fair to say I should just ignore it. But I find
             | it lowers the quality of discussion in a way I want to
             | protest, so I'm doing so. It's a zero effort "dunk" posted
             | reflexively.
             | 
             | If you'll let me ramble a little bit, part of why I push
             | back on this sort of behavior is because of growing up
             | around evangelical extremists. A huge part of their
             | behavior is using and re-enforcing what I call "thought
             | ending cliches." These are one size fits all rhetorical
             | quips that function to shut down conversation. "Well it's
             | all part of God's mysterious plan" being the most basic
             | famous one. Climate change? "It goes in cycles." You get
             | the idea.
             | 
             | This kind of empty reflexive contrarian snark does the
             | exact same thing, so no, I don't see it in a positive
             | light. It's not just a joke, it's a joke intended to shame
             | people into stopping discussion.
        
         | PaulHoule wrote:
         | From a young age I've combed the shelves at public libraries
         | and found handbooks on battery technology.
         | 
         | Often 1/3 of the book is devoted to ordinary batteries and the
         | other 2/3 are devoted to "reserve batteries" which are able to
         | deliver a high power density for a short time to power a
         | missile or something like that. There was a huge amount of
         | research on those and I think it's easier to make a battery
         | work if it doesn't have to last very long.
         | 
         | NiMH batteries seemed to come out of nowhere. I remember Sony
         | licensing the technology for "InfoLithium" batteries that
         | eventually took over the world.
         | 
         | The market for batteries is bigger than it ever was. Grid scale
         | batteries relax many constraints: molten salt batteries might
         | be practical there. The South Africans thought this kind of
         | battery might be relevant for cars in the late 1970's and
         | 1980's
         | 
         | https://www.afrik21.africa/en/south-africa-the-zebra-salt-ba...
         | 
         | and it might be again with electric cars legitmized and if oil
         | is out of reach.
        
           | DebtDeflation wrote:
           | >NiMH batteries seemed to come out of nowhere.
           | 
           | My initial thought when I saw your post was "weren't these
           | just a relatively contemporaneous improvement on NiCad
           | batteries?"
           | 
           | Checked Wikipedia and nope:
           | 
           | NiCad - Invented in 1899 and commercialized in 1910.
           | 
           | NiMH - Invented in 1967 and commercialized in 1989.
           | 
           | I had no idea there was such a long gap between the two.
        
             | acdha wrote:
             | I wonder if there was some kind of economic inflection
             | point -- it felt like that in my memory, too, where it felt
             | like NiCad was advertised more as new thing in the 80s
             | before getting replaced with NiMH. I wonder how much that
             | perception was steered by what was common in the car
             | battery space since that was probably the most known
             | rechargeable battery for a long time.
        
         | ahartmetz wrote:
         | I thought of it as well, with the same result: this one looks
         | like it could actually work for a change...?
        
         | ksec wrote:
         | Nothing wrong with reposting it. As a matter of fact I think
         | this should be posted every time there is a new battery
         | announcement so we can all do the tick boxes.
         | 
         | [ ] it lacks thermal stability at low or high temperatures. [ ]
         | it is too likely to catch fire or explode. [ ] it is
         | impractical to manufacture at scale.
         | 
         | These are the only three I see as problematic or unknown. Which
         | is not that bad.
        
         | ReptileMan wrote:
         | True ... but we need new order or two of battery performance
         | improvements, so the breakthrough must come from somewhere.
        
         | Tade0 wrote:
         | I have a very simple criterion: Do they have a production
         | process designed for this new technology? That's the final step
         | to commercialization and is often the barrier that prevents new
         | chemistries from entering the market.
        
       | cstross wrote:
       | 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 wrote:
         | 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?
        
           | red_trumpet wrote:
           | 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.20220682
           | 8?u...
        
             | marcosdumay wrote:
             | Just to add, yes, that paper is about solid state
             | batteries.
        
           | dahfizz wrote:
           | > 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
        
             | jacoblambda wrote:
             | 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/10.1080/21
             | 663831.2022.2...                   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 degC. A molten Na anode (melting
             | point=98 degC), a molten sulfur cathode (melting point =
             | 118 degC) and ceramic b'-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 degC.
             | 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 degC-35 degC.
             | RT-Na/S batteries can completely convert S8 to Na2S, so
             | they have a high theoretical energy density (1274 Wh kg-1)
        
           | Valgrim wrote:
           | 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
        
         | uoaei wrote:
         | 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 wrote:
           | 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.
        
         | walnutclosefarm wrote:
         | 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 wrote:
         | 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
        
           | passwordoops wrote:
           | 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
        
         | Someone wrote:
         | 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://onlinelibra
         | ry.wiley.com/doi/10.1002/adma.202206828?u...), so I guess you
         | misread that.
        
         | tremon wrote:
         | _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 wrote:
           | 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 wrote:
         | 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
         | 
         | 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
         | 
         | "...thermally treated at 300 degC 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 degC 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.
        
         | marcosdumay wrote:
         | The paper, that red_trumpet posted down on the replies is about
         | solid state NaS batteries.
        
         | cpfohl wrote:
         | I (incorrectly it seems) assumed that "molten" was just part of
         | the manufacturing process. This take makes more sense.
        
         | bluelightning2k wrote:
         | 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.
        
         | deng wrote:
         | 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.
        
           | analog31 wrote:
           | A somewhat shorter lifespan might be a decent trade if the
           | materials are much more recyclable and if mining is produces
           | less pollution.
        
             | marcus_holmes wrote:
             | also if the batteries are cheap enough they can be
             | considered "partially rechargeable" and swapped out when
             | the capacity fades too much
        
               | analog31 wrote:
               | I suppose partially worn out batteries can also find new
               | uses, such as stationary power reserves, where they're
               | not being cycled a lot.
        
           | davrosthedalek wrote:
           | Is it 0.05% of the remaining capacity, or of the initial
           | capacity?
        
           | ksec wrote:
           | > 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.
        
             | deng wrote:
             | 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)
             | 
             | 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]
        
             | abdulmuhaimin wrote:
             | The faster battery life deterioration might even be
             | desirable for those manufacturers with planned obsolescence
             | in mind, especially phone manufacturers
        
             | onlyrealcuzzo wrote:
             | Can they be recycled to get back close to 100% capacity?
        
             | splitstud wrote:
        
             | dachryn wrote:
             | My LifePo4 battery has a 6000 cycle guarantee at 60%
             | capacity.
             | 
             | So its not even close yet
        
               | Retric wrote:
               | The question is more how many kWh can you store and
               | extract over a lifetime at a given cost rather than how
               | many cycles can it take.
               | 
               | If the 5999th charge is only holding appropriately 60% of
               | a LifePo4 battery you don't get 6,000 cycles * full
               | battery capacity.
        
               | deng wrote:
               | > So its not even close yet
               | 
               | Yes, if you compare just capacity fade, that's true. But
               | the longevity of LiFePo4 comes with a lower charge
               | density than Li-Ion, about 170 mAh/g. This NaS battery
               | currently has 1017 mAh/g, so almost a factor of 6. If the
               | capacity is higher, you don't have to cycle as often, but
               | of course, mileage depends on the use case.
        
               | cogman10 wrote:
               | That lower capacity comes at a cost cut and a huge
               | materials advantage. LFPs are made of highly available
               | materials. (Lithium, iron and phosphate).
               | 
               | The higher capacity NMC batteries are constrained on
               | nickel production.
        
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