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Power Science Technology

Silicon 'Sandwiches' Make For Lightweight, High-Capacity Batteries (newatlas.com) 31

A team at Clemson University has come up with a new design that overcomes some of the problems with incorporating silicon into lithium-ion batteries, "enabling them to demonstrate a lightweight and multipurpose device that could be used to power satellites and spacesuits," reports New Atlas. From the report: Scientists have been investigating the potential of silicon in lithium-ion batteries for a long time, and with good reason. Using the material for the anode component instead of the graphite used today could increase the storage capacity of these devices by as much as 10 times, but there are a few kinks to iron out first. Silicon doesn't exhibit the same durability as graphite in these scenarios, tending to expand, contract and break apart into small pieces as the battery is charged and discharged. This causes the deterioration of the anode and failure of the battery, but we have seen a number of potential solutions to this over the years, including fashioning the silicon into sponge-like nanofibers or tiny nanospheres before integrating them into the device.

The new research out of Clemson University looks to shore up the dependability of silicon with the help of carbon nanotube sheets called Buckypaper, which we've also seen used in the development of next-generation heat shields for aircraft. These sheets were paired with tiny, nanosized silicon particles in what the team says is an arrangement much like a deck of cards, with the silicon particles sandwiched in between each layer. "The freestanding sheets of carbon nanotubes keep the silicon nanoparticles electrically connected with each other," says Shailendra Chiluwal, first author on the study. "These nanotubes form a quasi-three-dimensional structure, hold silicon nanoparticles together even after 500 cycles, and mitigate electrical resistance arising from the breaking of nanoparticles." The beauty of this approach, according to the team, is that even if the charging and discharging of the battery causes the silicon particles to break apart, they remain locked inside the sandwich and able to perform their function. This means that, theoretically, this functioning but experimental battery has a much higher capacity, which means the energy can be stored in much lighter cells, reducing the overall weight of the device. As a bonus, the use of the nanotubes creates a buffer mechanism that enables the batteries to be charged at four times the speed of current iterations, according to the scientists.
The research was published in the journal Applied Materials and Interfaces.
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Silicon 'Sandwiches' Make For Lightweight, High-Capacity Batteries

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  • Battery (Score:4, Insightful)

    by ledow ( 319597 ) on Wednesday September 02, 2020 @06:02AM (#60464922) Homepage

    Oh, look, another battery technology that we'll never hear anything of again, or ever see in a production battery.

    Can we give it up already?

    When I can *buy* that battery, then it's interesting. Until then, it's just a pet science project for a researcher who'll be working on carbon fibre, or plastic, or oil filtration next year when their PhD thesis is filed.

    • Re: Battery (Score:4, Funny)

      by Your Father ( 6755166 ) on Wednesday September 02, 2020 @06:22AM (#60464948)
      Pretty sure we will hear about it again, but this will be because Slashdot editors will post a dupe.
    • And as anyone knows, carbon nanotubes are a miracle substrate that solve everything! Err, just not today, sometime in the near future, honest.

    • Comment removed based on user account deletion
    • I understand your frustration, since I also recognise the general tendency to overhype everything, which brings nothing but dissappointment after you realise that none of these promising research projects materializes into something tactile.

      Having said that, particularly on the battery topic, these announcements need to be interpreted differently by learned people like yourself. The real message here is that our current battery technology is not limited by physics. A better battery is theoretically possible

      • by HiThere ( 15173 )

        Well, it's frustrating, but your sentence is wrong, it should read: ...none of these promising research projects materializes into something tactile this year .

        It's also true that some of them will never show up. But we can't tell which at this end of the development process. That's what development is about. And it's why having several different approaches is a good thing. Even so, we can't tell how long development will take. Saying "not this year" was wildly optimistic, but "not this decade" would b

    • "When I can *buy* that battery, then it's interesting." why? its interesting now. Once its on the shelf and being sold, its no longer interesting as that project is over. Don't read the articles if you are bored with them. its the same for all new tech, there are lots of attempts and ideas to get close to the silver bullet of that field
      • by ledow ( 319597 )

        Because every year I see a dozen of these stories, just on this site alone, and that's been the case for 20+ years.

        Number of them that ended up in a battery that you can hold in your hand? Almost entirely zero. Number that actually lived up to their "double capacity / halve the charging time" etc. promises? Almost none. Tiny incremental improvements at best.

        It honestly wears, especially in the battery area - it's constant, frequent, repeated, and annoying.

        I love tech. I love the idea of more powerful b

    • When I can *buy* that battery, then it's interesting.

      But know that someone will decry that posting as a slashvertisement.

    • Oh, look, another battery technology that we'll never hear anything of again, or ever see in a production battery. ... When I can *buy* that battery, then it's interesting.

      For these things to get to where you can buy them, they need to be engineered into a product. (Some of them will be. Most will not make it to product - because they turn out to have problems, cost too much, or something BETTER wins in the market.)

      For them to be engineered into a product, the engineers need to know about them. Articles

  • by Rei ( 128717 ) on Wednesday September 02, 2020 @06:33AM (#60464960) Homepage

    Scientists have been investigating the potential of silicon in lithium-ion batteries for a long time

    Use of silicon (in conjunction with graphite) is already mainstream in high-capacity batteries. The goal is to increase the silicon percentage and decrease the carbon percentage, as the silicon stores far more lithium.

    Using the material for the anode component instead of the graphite used today could increase the storage capacity of these devices by as much as 10 times

    No. It could increase the capacity of the active anode materials by (about) an order of magnitude. But this is just a fraction of the mass and volume of a cell.

    The new research out of Clemson University looks to shore up the dependability of silicon with the help of carbon nanotube sheets called Buckypaper, which we've also seen used in the development of next-generation heat shields for aircraft. These sheets were paired with tiny, nanosized silicon particles in what the team says is an arrangement much like a deck of cards, with the silicon particles sandwiched in between each layer.

    Sounds expensive. What the world needs far more than capacity is low price per kWh. The main reason that automakers don't put more batteries into EVs today isn't because they couldn't design an EV that could hold more batteries or that the vehicle would be too heavy for the road - but because it would cost so much it'd drive the vehicle out of the market.

    That said, there are applications where density matters more than cost. Just not the big ones.

    "The freestanding sheets of carbon nanotubes keep the silicon nanoparticles electrically connected with each other," says Shailendra Chiluwal, first author on the study. "These nanotubes form a quasi-three-dimensional structure, hold silicon nanoparticles together even after 500 cycles, and mitigate electrical resistance arising from the breaking of nanoparticles."

    Performing 500 cycles is a good start (better than a lot of stuff at the research stage), but in the real world you want a few thousand. I'd have to look at the degradation curve (haven't read the paper) to see if it looks like it'd scale.

    As a bonus, the use of the nanotubes creates a buffer mechanism that enables the batteries to be charged at four times the speed of current iterations, according to the scientists.

    I could see this as being beneficial for the anode side, but it does nothing to alter the cathode diffusion rate. But at the very least, if they really are getting much improved anode ion diffusion rates, it'd at the very least reduce charge taper, which generally is limited by anode constraints today.

  • This week's miracle battery show presents: Silicon 'Sandwiches'
  • Seems to have some major issues when that is the the target application.

    • What about aircraft? Electric powered aircraft are already flying, but the battery weight is still the main show stopper.
      • by gweihir ( 88907 )

        They say satellites and spacesuits. This stuff is probably prohibitively expensive. Otherwise aircraft would be indeed the obvious application.

  • No! Scientists are supposedly to instantly know 100% about everything in their field!
  • Most advances in lab battery research experiments claim improvements in energy density of 5X to 10X. Probability would suggest that at least of these improvements would actually reach the market. Instead, linear improvements in the 5% range have been more common. Presumably this is due both to entrenched manufacturing and marketing practices and, generously, difficulties in reducing the lab results to manufacturing practice. I don't expect Tesla's Battery Day announcements to be much different, but hope sp
  • Awesome. Now get the technology into the hands of the mass-produced and commonly-available battery manufacturers. Don't just give it to the damn electric car companies. I want this in my UAV, thanks.

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