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Power Technology

Superior Anode For Lithium-Ion Batteries Developed 77

Posted by samzenpus
from the power-up dept.
RogerRoast writes "The anode is a critical component for storing energy in lithium-ion batteries. The Berkeley Lab (D.O.E) has designed a new kind of anode that can absorb eight times the lithium of current designs, and has maintained its greatly increased energy capacity after over a year of testing and many hundreds of charge-discharge cycles. According to the research published in Advanced Materials they used a tailored polymer that conducts electricity and binds closely to lithium-storing silicon particles, even as they expand to more than three times their volume during charging and then shrink again during discharge."
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Superior Anode For Lithium-Ion Batteries Developed

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  • by Joce640k (829181) on Sunday September 25, 2011 @11:51AM (#37508286) Homepage

    I couldn't see the main article because it requires subscription but how much extra capacity does this actually translate into? (Assuming it works...)

    • by vlm (69642) on Sunday September 25, 2011 @12:03PM (#37508354)

      Energy capacity (assuming constant voltage) is linear with stored charge.. stored charge is linear with quantity of active species, which is going up by a factor of 8, so I'd guess about 8 times.

      Voltage is never constant under high discharge rates... lead acid "car" batteries are famous for covering their plates temporarily with gas (h2) and all batteries dump some fraction of their capacity into their internal resistance. For a good example try pulling 10 amps out of a giant deep cycle marine battery, then outta a nicad C size cell, then outta a pre-alkaline, pre-heavy duty zinc C size cell (think radio shack battery of the month club red battery).

      expand to more than three times their volume during charging and then shrink again during discharge

      Well, that's fairly terrifying word choice to anyone who did extreme stuff with prior battery techs. Expanding lead acid cell means the vent is clogged and you're about to get a large dose of flammable H2, corrosive electrolyte, and splintering plastic. Expanding lithium means its about to go kaboom. "Expand" is not a cool choice of words around battery people. Call it "volumetrically challenged" or something.

      • by DamonHD (794830)

        What fraction of the entire cell is the anode, and thus how much 'sometimes unused' space has to be left for this anode when fully turgid, and thus by what fraction does this knock down Wh/l energy density, do you think?

        Anyhow, it seems as if it might be quickly commercialisable and just needs a matching top-notch cathode! B^>

        Rgds

        Damon

      • by Joce640k (829181) on Sunday September 25, 2011 @12:31PM (#37508492) Homepage

        I'd guess about 8 times.

        If that's true, and even if it only works out to six times in production then it almost solves the car battery problem. We can get about 100 miles with existing batteries and 600 miles is about as far as a normal person would want to drive in a day (ie. average 60mph for ten hours).

        (I say "almost" because of the following posts...)

        • Of course, it'll only cost 6-8 times more than existing technology...

          • by DamonHD (794830)

            That might even be worth it (per kWh) for some apps, such as smart phones. B^>

            Unless it's 6x--8x per l or kg in which case that's be the same price per kWh as the current lot (but a lot smaller and longer-lasting) and would be *wonderful*! I could run my house for a year on a small shed's worth!

            Rgds

            Damon

      • Re: (Score:3, Informative)

        by Anonymous Coward

        It's not the Lithium which is expanding. The silicon which stores the lithium expands and breaks into bits and pieces. That's the challenge in using Si as a Grahpite substitute in LIB.

      • Re: (Score:2, Informative)

        by Anonymous Coward

        "Expand" is not a cool choice of words around battery people. Call it "volumetrically challenged" or something.

        In lithium-ion batteries, that's exactly what happens though. As lithium fills up the active material, there is a volume expansion. No gases are produced in li-ion batteries unless the electrolyte heats up, the problem with volume expansion is that it can form cracks in the material and reduce its mechanical and electrochemical integrity which usually results in high capacity fade with time (I guess these guys have figured it out though).

      • Call it "volumetrically challenged" or something.

        Wouldn't it be "volumetrically gifted"?

    • I couldn't see the main article because it requires subscription but how much extra capacity does this actually translate into?

      That's a good question that I've never found an answer to. It depends, of course, on how much of the battery is the anode.

      It's important to remember all the silicon anode results we've heard about in the past. Some of these are moving forward without this, so the gain will be even less that you would at first think. However, I think this could have better longevity - the battery

    • by msauve (701917) on Sunday September 25, 2011 @01:23PM (#37508780)
      Although you can't get to the paywalled article, there is a barely legible chart [wiley.com], which shows the specific capacity, in mAh/g, to be ~2200. Current Li-Ion batteries, which use a graphite based anode [wikipedia.org], have a specific capacity of ~350 mAh/g [pnl.gov]. So 2200/350= ~6 times the capacity.
  • by drobety (2429764) on Sunday September 25, 2011 @11:55AM (#37508312)
    There has been many nice headlines over the months (years) about such and such new advances in battery technology. Surely it's nice, but now I am becoming jaded with such articles. Here is what I want now: "New AAA batteries lasting twice as long as those currently sold reach the market // blah blah ... as measured by independent testing ... blah blah"
    • Maybe *you* only want to know about things once they are no longer R&D and are just lumpen consumer goods available in your local B&M.

      Others may like to know about research, both blue-sky and nearer commercialisation.

      The fact is that batteries *have* improved vastly over recent time, but not possibly by quanta and in formats that excite you.

      I'm rather impressed by the LiFePO4 battery that I have rigged up alongside my 2kWh of SLA gel to reduce cycling of the latter, at several times the energy densi

      • by Twinbee (767046)

        What I never tend to see is a simple site with various graphs charting this progress (of market available products). Whether it's the cost/GB of SSD storage, highest temperature found for a superconductor, or indeed the joules (or watts) per litre (or mass) of battery. I'd just love to see the curves, and see how they grow over the years.

        • by DamonHD (794830)

          Getting like to compare with like is astonishingly difficult post hoc in my experience, but I did it many many years for a defence company and was able to project commodity CPU performance forward about a decade (it turned out) across families and within a single family (x86) reasonably well.

          Probably few journalists have the time to embark on building such curves from scratch, though I agree that they are interesting.

          Maybe do some yourself and stick them in Wikipedia?

          Rgds

          Damon

      • by Spoke (6112)

        I'm rather impressed by the LiFePO4 battery that I have rigged up alongside my 2kWh of SLA gel to reduce cycling of the latter, at several times the energy density by volume and weight (and not that expensive).

        That sounds like a cool project - got any details of it on a website somewhere?

        But I went and haggled and bought it straight off a vendor's R&D bench armed with the knowledge that it wasn't likely to turn up in consumer gear in that form, at least not for a year or two.

        I didn't think it was that hard to find LiFePO4 batteries these days online... What specifications/format were you looking for in a battery?

        • by DamonHD (794830)

          Hi,

          Here's the project: http://www.earth.org.uk/LiFePO4-battery-testing-with-solar-PV-off-grid-system.html [earth.org.uk]

          I went to see the vendor at its office because it had some interesting stuff on sale, and discussing what they were working on stumbled upon this LiFePO4 battery. It's prismatic (so compact) and has a BMS built in, suitable to accept nominal 12V solar PV directly at its inputs. (It has 4 wires; PV in and nominal 12V out, though a common +ve rather than -ve which is a slight nuisance.) BMS, ie solar ch

    • Re: (Score:2, Interesting)

      by Anonymous Coward

      Not gonna happen any time soon. The energy density (per unit volume) of alkaline long-life cells is about 50% higher than any other viable technology we have available. It seems unlikely anything is going to revolutionise this technology. Almost all current research is targeted at improving lithium cells, which are the next best (lower density than NiMH, but that technology has severe limitations on longevity that are not going to go away). Lithium is better in terms of density per mass, but what it abs

      • by Mprx (82435)
        A good modern low self-discharge NiHM (eg. 2nd generation Eneloop) can survive more charge cycles than lithium ion, and has better self-discharge performance. Capacity is a bit worse than traditional NiMH, but it's still a lot better than NiCd. It would probably be possible to build a NiMH that meets your specifications for electric vehicles.
      • by dr2chase (653338)

        I would suggest that smaller and lighter vehicles are a more sensible path to pursue. Smaller cars means cheaper batteries, which means that current technologies are affordable after all.

        Other thing I find interesting, and unclear from the article, is whether the capacity of the battery is proportional to the lithium in the battery, regardless of anode technology. That means that the use of these batteries would spike demand for lithium both by increasing the popularity of e-cars and by putting more lithi

        • I would suggest that smaller and lighter vehicles are a more sensible path to pursue. Smaller cars means cheaper batteries, which means that current technologies are affordable after all.

          While there's still quite a bit of room for improvement in weight savings, consider that developing a battery that has higher energy density will allow you to put fewer pounds of battery into an EV, of whatever design.

          Car makers would love to make their vehicles lighter for no additional cost. Right now steel is cheaper than carbon fiber. You need a car of at least a certain weight to meet the safety requirements. As long as batteries remain weighty, you have to add even more weight in structural support

      • by Anonymous Coward

        (lower density than NiMH, but that technology has severe limitations on longevity that are not going to go away)

        This isn't wrong, it's ridiculously wrong. NiMH batteries are used in the Toyota Prius, where almost all of them last for thousands of charge/discharge cycles. The *prototype* of all NiMH batteries lasted 500 c/d cycles and most modern NiMHs last on the order of 4000 cycles or more:

        Interest grew in the 1970s with the commercialisation of the Nickel hydrogen battery for satellite applications. Hydride technology promised an alternative much less bulky way to store the hydrogen. Research carried out by Philips Laboratories and France's CNRS developed new high-energy hybrid alloys incorporating rare earth metals for the negative electrode. However, these suffered from the instability of the alloys in alkaline electrolyte and consequently insufficient cycle life. In 1987, Willems and Buschow demonstrated a successful battery based on this approach (using a mixture of La0.8Nd0.2Ni2.5Co2.4Si0.1) which kept 84% of its charge capacity after 4000 charge-discharge cycles. More economically viable alloys using mischmetal instead of lanthanum were soon developed and modern NiMH cells are based on this design.[9]

        For comparison, lithium-ion batteries are often only rated for something like 200 c/d cycles, with the best commercial-grade lithium-ion batteries not rated for longer than 1000 c/d cycles.

        • For comparison, lithium-ion batteries are often only rated for something like 200 c/d cycles, with the best commercial-grade lithium-ion batteries not rated for longer than 1000 c/d cycles.

          That's only true if you consider LiFePO4 different from lithium ion. Some of them have demonstrated 5000 cycles. Unfortunately they are more expensive and have about half the energy density of conventional Li-Ion cells. If they come down in price , or if their capacity can be boosted without making them more expensive, th

        • Look into the lithium-ion batteries offered by ABSL, a European satellite battery company. They aren't really "commercial" grade as they are designed to be used on spacecraft, but they can survive upwards of 10,000 cycles given appropriate depth of discharge constraints. They are also significantly lighter than nickel-hydrogen packs.
    • Re:Jaded (Score:5, Insightful)

      by Animats (122034) on Sunday September 25, 2011 @12:47PM (#37508586) Homepage

      I am becoming jaded with such articles.

      What's annoying are all these material science articles where someone has made a new material at lab-scale and this is immediately extrapolated to commercial products Real Soon Now. About one of those appears each week. This is one of the saner ones, though.

      The Great New Material usually turns out to have some problem. It costs too much to make, it's too brittle, it won't work when hot or cold, it's too hazardous, or it has a short lifespan in the intended application. Sometimes this is overcome, but most of the time, not.

      There's nothing wrong with having articles about this stuff, but writers should be clear on where they are in the range between "theoretical chemistry indicates this molecule would be insanely great" and "the product is shipping in volume".

      • There's nothing wrong with having articles about this stuff, but writers should be clear on where they are in the range between "theoretical chemistry indicates this molecule would be insanely great" and "the product is shipping in volume".

        You have to admit, though, that it's at least more exciting than the latest display tech of the week.

    • Here is what I want now: "New AAA batteries lasting twice as long as those currently sold reach the market [...] as measured by independent testing ...

      You should rethink your crush on the cute red-haired girl, and maybe settle for deoxygenated speaker cable instead--where basic research to applications cycles at the speed of CTRL-S in PowerPoint. I guess I'm jaded, too, about erection returns.

      Serious question: How many headlines does it take to change a battery? Plenty, if you get sucked into the cul de s

    • by sjames (1099)

      I'll take ANY of these many amazing new breakthroughs in battery technology actually reaching the market.

      For that matter, It would be nice if LiIon batteries already in production weren't all embedded in oh so special battery packs that cost way too much. They are made in convenient packages looking much like alkaline batteries and chargeable with standard chargers elsewhere. I use 3.7v 900 mAh 14500 (about the size of a AA) with a built in protection circuit and they work quite well but I have to order the

    • There has been many nice headlines over the months (years) about such and such new advances in battery technology.

      Yep, and battery tech has improved steadily during the same time. The reduction in the sizes of mobile phones is to a large extent due to better battery tech. Black and decker has started selling batteries for their power tools that can recharge in minutes. The iPad would not have been possible with the batteries we had 10 years ago, and so on.

      Yea, some of these advances never make it. Some onl

  • by ickleberry (864871) <web@pineapple.vg> on Sunday September 25, 2011 @12:59PM (#37508674) Homepage
    There are many improved versions of the Li-Ion battery that last longer (as in more cycles) but they never seem to reach the market. Yeah feck it you can buy loose 18650 LiFePO4 cells and even lithium based supercapacitors but name one phone or laptop a normal person can easily buy with anything other than the bog standard 400-500 cycle-then-dead Li-Ion battery?

    I expect that the reason for this is quite sinister - Li-Ion batteries are used to enforce planned obsolescense, which is why standard cells are often packed into an overpriced proprietary plastic casing before sale. Manufacturers of consumer electronics don't want batteries that are still good after thousands of cycles. Apple also deserves a mention for pioneering the idea of packing the battery into the hard to open case of the phone/laptop itself, forcing 99% of the people who own these products to buy a new one as soon as the battery dies.
    • by Urza9814 (883915)

      The phone that I bought 6 years ago has an Li-Ion battery. I've been charging it nearly every night for 6 years (though it's almost never entirely dead at that point), and it'll still go a week on a single charge. I've never noticed any problems with Li-Ion capacity reducing with age except in laptops...which I've always heard was more a problem of heat than charge cycles.

    • But did they only come up with this sinister plan once Li-Ion made its way onto their market, then?

      Because apparently that sinister plan wasn't in place for regular alkaline batteries.
      And it wasn't in plan for NiCd batteries.
      And while my older candybar phone still has a NiMH battery, my newer one has a LiPo ( I guess I skipped the Li-Ion generation ).
      And this while LiPo tech has been around for over a decade.

      Don't worry, LiFePO4's time in your cellphone will come (apparently it's already in use in the OLPC

    • by vijayiyer (728590)

      Maybe instead of a vast conspiracy, it's because LiFePO4 batteries have a much lower energy density? They can be charged much faster, but would you carry a 200W power brick to take advantage of it?
      Lithium based ultracaps have on the order of 10% of the energy density of Li-Ion batteries. Would you carry a laptop that lasted 30 minutes per charge?

      Most people will have their batteries replaced if it every stops holding a charge. Seems like a fair tradeoff to have devices last 30% longer per charge.

    • In case you haven't noticed, li-poly batteries have been in consumer devices for the last year or two. I have an Energizer XP2000 that has one. The iPhone4's non-replaceable battery is a li-po.

      • Which has almost no or very little increase in durability over standard Li-Ion. The main advantage of them is that they can be made into a nice proprietary shape

        Heat does negatively effect Li-Ion batteries, Ideally they are stored at a few degrees C and half-charged. There also seems to be a huge variation in the quality of these batteries. I know there are plenty of Nokia 6310i's around still on the original battery but my laptop battery from 12/2009 is already down to 57%
        • by jo_ham (604554)

          Yes, that "proprietary shape" ability means you can squeeze every last little bit of extra space in the device into useful battery capacity, unlike a battery shape that had to be designed to be removable (along with the space that has to be given up for the battery bay itself and the door mechanism etc).

          It sounds like you're suggesting the only reason manufacturers moved to LiPoly over Li-ion is because it meant they could make batteries that were incompatible with other devices.

          Oddly enough, the Li-poly ba

    • by jo_ham (604554)

      Apple also deserves a mention for pioneering the idea of packing the battery into the hard to open case of the phone/laptop itself, forcing 99% of the people who own these products to buy a new one as soon as the battery dies.

      It took me 10 minutes to change a dead battery in an iPhone 3GS, and that included making a cup of tea.

      The battery swap in a Macbook Pro is similarly very simple (it's as easy to get to as adding/changing RAM - the battery is right next to the RAM slots).

      If you think it's hard to open, you've been listening to the conspiracy theorists a little too much or you've never actually tried it yourself.

      Far from the built in battery being a sinister ploy to "enforce obsolescence", might I suggest Occam's Razor? Buil

    • by Solandri (704621)

      but name one phone or laptop a normal person can easily buy with anything other than the bog standard 400-500 cycle-then-dead Li-Ion battery?

      The number of charge cycles you can get out of a Li-ion battery depends on how deeply you cycle it. If you regularly charge it to 100% and drain it to 0%, it'll only last a couple hundred cycles. If you limit it between 25%-75% (like the Chevy Volt does) it'll last a lot longer.

      The reason why it's mostly laptops which suffer from early Li-ion battery death is be

    • I know nothing about batteries, but I do know that the current MacBook Pro & Air ship with a Li-ion that lasts 1000 charge cycles. That's a full 3x longer than my last generation MBP's battery lasted.
    • I expect that the reason for this is quite sinister

      It's not sinister at all, why it's perfectly legal and indeed encouraged. It's called Capitalism. And yes, it's inherently designed to eat up everything in sight. Still, no different to any other species that eats itself out of house and home on a regular basis. We are "smart", but not that smart.

    • LiFePO4 lasts longer in terms of cycles, but has half the energy density of standard LiIon (and lower nominal voltage), I think that's why you don't see it in appliances. But it's an interesting battery - it has very low internal resistance which means you can pull a LOT of current from it what makes it great for certain applications (intermittent usage, high peak-current). What's more the LiFePO4 chemistry is safe, it won't explode in your face because of a short. Another alternative are LiMn cells, they
      • by pinkeen (1804300)
        As far as the alternatives are concerned. Usually only LiPoly batteries are used in smartphones, etc. because other chemistries require sturdy metal casing (which is relatively HEAVY) and are hard to fit effectively in a thin, rectangular factor.
    • by tlhIngan (30335)

      Apple also deserves a mention for pioneering the idea of packing the battery into the hard to open case of the phone/laptop itself, forcing 99% of the people who own these products to buy a new one as soon as the battery dies.

      Yeah, because in a year's time when my laptop battery dies, I'll pay the $150 ($100 for a chinese OEM may-explode version) for a new one. NOT.

      Most consumers don't buy spare batteries. Check it out sometime on what phones you can buy third party Li-Ion batteries for, and the selection w

  • by Anonymous Coward

    We get a story about new tech promising an order-of-magnitude increase in the capacity of lithium batteries

    We have yet to see any come to fruition.

  • by frovingslosh (582462) on Sunday September 25, 2011 @06:02PM (#37510136)
    Sure, we all want this. And I realize I'm likely to get moded down, not because I'm saying anything wrong but because someone who saw the original story and was excited doesn't like hearing the truth. But I'm getting a bit tired of hearing about all of these advances in battery technology that never actually seem to make it to the marketplace, in spite of claims that the advance can quickly and easily be applied to current production techniques.. Of course if this stuff really panned out we wouldn't even need batteries, we would all be using those nano-particle based super capacitors that I read about here years ago.
  • Batteries are inherently a difficult component to innovate and develop. Putting aside limitations in chemistry and the costs involved, batteries are also subject to some of the toughest criteria before it'll even be considered viable for use in consumer products, operating temperatures, toxicity, size & weight, availability, longevity, stability & manufacturing scalability are some of the factors that need to be considered before new battery technology can be used. Once a battery meets all of the c
  • Does that mean that you need empty space surrounding the battery equal to three times the volume of the discharged battery? If that's the case, you get 8 times the charge capacity but it occupies 3 times the space so is it equivalent to slightly more than doubling existing batteries? Have I missed something?

    • by Rainwulf (865585)

      No, the anode matrix has the physical dimensions designed to store the lithium at its maximum size.
      This limitation of the anode matrix is why its incredibly dangerous to overcharge a lithium based battery, as once the anode matrix is full of lithium, it has nowhere else to go, hence.. boom.

      This technology is special in that its allowing a much greater growth in the size of the stored particles, while still maintaining electrical contact during discharge, and allowing the full particle size when charging. Th

  • I've read quite enough "miracle breakthrough" stories down the years to waste my time on this one. It'll be yet another bunch of beardy weirdies claming a theoretical result in the lab which is a magnitude short of the headline, but they have a plan to make a breakthrough (the plan being the only plan) real soon now. Insert more funding to continue.

    If it's not on the market, it's not news. End of story.

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