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Sand-Based Anode Triples Lithium-Ion Battery Performance 60

Zothecula (1870348) writes "Conventional lithium-ion batteries rely on anodes made of graphite, but it is widely believed that the performance of this material has reached its zenith, prompting researchers to look at possible replacements. Much of the focus has been on nanoscale silicon, but it remains difficult to produce in large quantities and usually degrades quickly. Researchers at the University of California, Riverside have overcome these problems by developing a lithium-ion battery anode using sand."
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Sand-Based Anode Triples Lithium-Ion Battery Performance

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  • by Anonymous Coward on Saturday July 12, 2014 @05:55AM (#47437115)

    I love the way that at the end of TFA there are links to pretty much the exact same story dating from 2013, 2012, 2009 and 2003.

    • Re: (Score:2, Funny)

      by Anonymous Coward

      The anomaly was caused by the submitter using one of the early prototype batteries to power his computer.

      Since then I've discovered that the battery actually steals electricity from the future, and the original submission is stuck in a time loop.

      Emmett Brown

      p.s. Great Scott!

    • by Rei ( 128717 ) on Saturday July 12, 2014 @08:37AM (#47437377) Homepage

      Commercial li-ion battery energy densities have continued to improve during that time period, including the commercial introduction of cells with silicon anodes. Of course, silicon anodes are a new tech, so there's a great deal of room for improvement, which probably won't come close to "maxing out" for a decade or more.

      Of course, that said, this article is your typical fluff piece following the guidelines of fluff science reporting.

      1. Present an oversimplified version of one technology challenge that may or may not address the biggest issue and certainly doesn't address all of them - but don't mention that.
      2. Introduce an outside-the-establishment loner with a passion - or at least someone you can try to present as "outside the establishment" and glaze over anyone who helped him.
      3. Loner gets a "vision" based on some everyday activity
      4. Present their solution and make it out to be a huge revolution that will certainly solve all our problems - if they can only get corporate backing / funding!

      I think these sort of articles hurt the image of science because people read them, think "OMG, all our problems are solved!", then when everything's not solved afterward, fail to trust science in the future. For example, in this case, the most important element to improve is the cathode, not the anode. And cathode improvements are less common and usually less major than anode improvements. There's also tons of different anode improvements out there in various stages of research. Pretty much all of the silicon ones get way better than graphite or amorphous carbon.

      That doesn't mean that this isnt an important paper - actually, from looking at it, it looks pretty good. It's just not "all that".

      BTW, anyone know how credible this journal is? I see it's hosted on Nature.com but not part of Nature, and I tried to find an impact rating for it but couldn't.

  • The article suggests that making nano-scale silicon by using magnesium to remove oxygen solves the usual degrading issues. Why is this? Does the quartz lattice have optimal conduction geometry, which is somehow preserved after the oxygen is removed?
    • by tsa ( 15680 )

      I don't think it suggests that at all. It says the Mg is used to make porous silicon out of sand (neat trick), but nothing about how to prevent the porous silicon from reacting with oxygen from the air. So I take it you have to use the porous Si in an oxygen free environment. That shouldn't be too hard to make in a battery though.

      • by jdagius ( 589920 )
        @tsa > I don't think it suggests that at all.

        Did you read TFA? It says. "In this very simple process, the salt acted as a heat absorber while the magnesium removed oxygen from the quartz, resulting in pure silicon. "

        So the article does indeed 'suggest' that Mg is removing O. My question was concerning how is this oxygen removal related to creating porosity. Or not.

        In any case, it seems likely that some formerly filled space must be vacated to create porous openings.

        Does anyone know how this h
  • by ThreeGigs ( 239452 ) on Saturday July 12, 2014 @07:34AM (#47437273)

    Looking at the actual research paper, all I see is improved durability, _not_ increased capacity. Yet the article claims you'd only need to "charge every three days instead of every day".

    Am I reading the research paper wrong or is everyone else?

    • I think the author messed up. Improved durability, but not capacity.
    • by Rei ( 128717 ) on Saturday July 12, 2014 @08:43AM (#47437401) Homepage

      1024 mAhg1 is excellent capacity even vs. brand new graphite or amorphous carbon, about 3x as much as graphite's maximum. Silicon's theoretical max is 8-10x that of graphite, but the main problem with it is durability, it tends to tear itself apart on loading. There are silicon anodes in some newer li-ion cells on the market, but the tech is in its infancy.

      That said, the real papers you want to be on the lookout for are cathode improvements, there's a lot more potential for volume/mass reduction there than in the anode. But it seems to be a more difficult challenge. Getting a 3x improvement in anode density is absolutely not the same a getting a 3x improvement in battery life.

      • That said, the real papers you want to be on the lookout for are cathode improvements, there's a lot more potential for volume/mass reduction there than in the anode.

        Exactly, all articles I can remember offhand for the cathode talk about a capacity of less than 200 mAh/g for existing cathode chemistries. So the cathode would make up most of the weight of the battery.

        If the technology from TFA works out, maybe we can get a 20% - 30% improvement in overall energy density.

    • That said... (Score:5, Informative)

      by Rei ( 128717 ) on Saturday July 12, 2014 @08:55AM (#47437451) Homepage

      ... the greater your capacity, the less cycle life matters. If you want an EV that battery that will run a 250Wh/mi vehicle for an average 20 miles a day for 15 years, then you want it to cycle through about 30MWh. If you use a 100 mile (25kWh) battery pack, then that's 1100 cycles. If you use a 200 mile (50kWh) battery pack, then that's 550 cycles. If you use a 400 mile (100kWh) battery pack, then that's a mere 275 cycles. Actually, the improvement is even better than that in the real world, because the greater your capacity vs. how far you're actually driving, the more you can cycle the cells through a less destructive state of charge range rather than doing deep discharges.

      A lot of people picture battery packs in EVs backwards, they think that things like hybrids stress the packs the least, PHEVs moderately, and EVs the worst. But it's reversed. If you look at how big hybrid packs are vs. how much electric range they hold, you'll see that they're disproportionately large, even after you factor in any differences in Wh/kg. The reason is that because hybrid packs get cycled so much, they have to keep the cycling in a very narrow state of charge range, only allowing shallow discharges. So if you only have a narrow discharge range, you have to make your pack bigger to make up for it. EVs can discharge through much more of their pack because they need fewer total cycles and only rarely go down toward the lower end of their allowable discharge range. Some EVs also let you limit the max that your pack charges up to to further extend lifespan (it's usually destructive both to use the very top end and the bottom end of the discharge range).

      • Some EVs also let you limit the max that your pack charges up to to further extend lifespan (it's usually destructive both to use the very top end and the bottom end of the discharge range).

        I wish I could get my laptop to do that. It spends most of its time in a dock anyway, endlessly cycling between 100% and 95% of capacity, eating up the limited number of charge cycles to no benefit.

        • by smaddox ( 928261 )

          That's not how it works. Degradation is much larger for deep cycling than for shallow cycling. You're better off leaving your laptop on the charger when not in use. Note, this only applies to modern laptops with regulated charging circuits.

      • Re:That said... (Score:4, Interesting)

        by swillden ( 191260 ) <shawn-ds@willden.org> on Saturday July 12, 2014 @11:23AM (#47437985) Homepage Journal

        Some EVs also let you limit the max that your pack charges up to to further extend lifespan (it's usually destructive both to use the very top end and the bottom end of the discharge range).

        That is the theory, but real-world experience with the world's most successful EV (Nissan LEAF) isn't bearing it out. There doesn't appear to be any significant benefit to limiting charging to the 80% level. What is proving to matter, a lot, is temperature. The risks of very cold temperatures are so extreme that the cars have built-in battery heaters (powered by the batteries, obviously) to protect against them, so in practice cold just reduces range, but hot temperatures seriously impact battery longevity.

        Another theoretically-predicted battery-killer that is not showing real-world degradation is quick charging. I believe Nissan has even stopped telling people they should limit the amount of level 3 charging they do.

        Excellent points about larger capacity batteries needing to survive fewer cycles, though.

        • by 7-Vodka ( 195504 )

          I'm sorry but the evidence just does not bear out your views at all. There is no compelling evidence that warm temperatures are bad for battery chemistry, in fact under laboratory tests the batteries last longer with fast charging and warm temperatures.

          Go look at evtv.me. Those guys actually do the experiments.

          The myth that nissan leafs have problems with warm temperatures is still not backed up by anything except for whining.

          • Actually there's quite a lot of data, quite widely reported. Google it.
          • by AaronW ( 33736 )

            Google for the Leaf issues in hot climates like Arizona and Texas where some owners lost 40% of their capacity in two years. There's a reason why most EV manufacturers have active battery cooling.

    • by dbIII ( 701233 )

      Looking at the actual research paper, all I see is improved durability, _not_ increased capacity

      It's an anode. Capacity comes from the electrolyte instead.

  • Launch date (Score:4, Insightful)

    by kingsaj2 ( 1390849 ) on Saturday July 12, 2014 @07:54AM (#47437313)
    Can we have announcements when these products are actually launched and are in use. Every month we hear of some new battery tech that will revolutionise everything in 5+ years time.
    • Re:Launch date (Score:5, Insightful)

      by rtb61 ( 674572 ) on Saturday July 12, 2014 @10:03AM (#47437669) Homepage

      Here is the rub, as they continually improve batteries committing to a production line becomes harder. Getting say fifteen years of life out of a battery production line becomes impossible with batteries improving every year and your production line being way behind latest technology.

      So there are certain levels in development where sufficient gain is made to commit to a production line even though the batteries will be out of date or the production line is based around a much reduced life with substantial impact on battery price. This is aided by government subsidises, making it possible to initiate a battery production line with less than optimal outcomes.

      Of course producing batteries builds the infrastructure and pays for more development. It is getting pretty obvious though that full scale electric vehicles are no longer that far off as battery technology continues to develop and companies can commit to major battery production lines with a required life to pay for that production line.

      • On top of these points I would like to add scale-up. Being able to produce an improved button-sized battery won't cut it. You'll need tons and tons of the new material, which means a stable and efficient production line is needed. And, of course, you'll need to develop and build said production line, which is something that the lab-rats often just wave their hands over, dismissing it as engineering "details".

    • by idji ( 984038 )
      please unsubscribe from "news for Nerds". We are here for news, and we are nerds, we want new ideas.
    • Not all concepts will make it to market. For varied reasons. Sometimes it's simply a matter of to restrictive/expensive patent licensing. But mostly some unforeseen problem happens further on in development that causes the whole thing to fizzle away to nothing.

      The experience we gain from both the initial research, and the failure is invaluable. Personally I love reading about materials research, even if I don't understand all of it, the time I spend researching to learn is well worth it.

    • It's easy. Since my crystal ball seems to be broken, we can just use yours.
  • I hear they make computers out of the stuff.

    • They also fill hydrocarbon deposits with it, as it keeps the veins open to the well bore after fracturing.

      If it becomes useful battery technology, perhaps we can mine it it Texas and North Dakota when the oil and gas play out.

    • Actually, not yet.
  • What are the costs going to be on these? If they're expensive like the Sony VTC5, I don't think I want to buy them...
  • Sand! (Score:5, Funny)

    by PPH ( 736903 ) on Saturday July 12, 2014 @10:59AM (#47437875)

    Our energy supply is still at the mercy of those damned Arabs!

  • They'd already tried several different materials - meat...fowl...crawdads. But when there was no crawdads, they tried sand. "They tried sand" you ask. They tried sand.
  • Silica is a well known carcinogen. http://ntp.niehs.nih.gov/ntp/r... [nih.gov] Our lab will not be messing with that shit, we will be looking for something safer! And if silica was in commercial batteries think how many members of the public might be exposed.
  • Yet another story about a 3X or 10X or whateverX improvement on Li-Ion batteries that will never, ever get out of the lab. or if it does, will be too delicate or too slow or too expensive or too whatever to use in electric cars.

    If we ever do get the electric car, then we only have to start work on the 86 or so nuke power plants of the same size as the one at Palo Verde, Az, our largest, in order to completely replace petroleum and leave the oil in the ground. Of course, the sad thing there is going back to

Research is what I'm doing when I don't know what I'm doing. -- Wernher von Braun