9 votes

Sionic Energy unveils 100% silicon anode battery with high energy density

8 comments

  1. [2]
    Wish_for_a_dragon
    Link
    I think it’s important to note that this is not a replacement for the lithium in a lithium-ion battery, but for the graphite. Instead of a lithium-graphite or lithium-nickel mix, it would be a...

    I think it’s important to note that this is not a replacement for the lithium in a lithium-ion battery, but for the graphite.

    Instead of a lithium-graphite or lithium-nickel mix, it would be a lithium-silicon mix.

    We’re still going to be dependent on lithium mined from abroad and reclaimed from recycled tech, but from a cost perspective I can think of few things cheaper than silicon for industrial production.

    8 votes
    1. arch
      Link Parent
      I went and did some quick Google based research after reading your comment, because I know that graphite is cheap. Apparently, graphite is currently cheap than silicon, possibly by a large margin...

      I went and did some quick Google based research after reading your comment, because I know that graphite is cheap. Apparently, graphite is currently cheap than silicon, possibly by a large margin --some estimates I read put it at 100x more expensive per kg for the purity of silicon needed for anode material. I did read that with scaling, silicon could become cheaper than graphite.

      Where it really seems to shine is in the possibility of greater energy density, enabling smaller, lighter batteries with greater energy capacity than we have now. I've skimmed a few articles that seem to be trying to compare cost per kwh for these batteries instead of the cost of manufacturing.

      10 votes
  2. [6]
    scroll_lock
    Link
    Comment box Scope: summary, information Tone: neutral Opinion: none Sarcasm/humor: none The energy density of a battery determines how much electricity it can store in a given physical volume....
    Comment box
    • Scope: summary, information
    • Tone: neutral
    • Opinion: none
    • Sarcasm/humor: none

    The energy density of a battery determines how much electricity it can store in a given physical volume. This is important for space-limited use-cases like vehicle and phone batteries.

    A new battery chemistry coming to production soon could offer a higher energy density than many existing products.

    The two companies say silicon anodes can boost energy density by up to 50 percent versus today’s best nickel-rich batteries, and reduce EV charging times to 10 minutes or less.

    I assume they're referring to DC charging. I don't know exactly how this compares to current charging times (the article claims "one-third faster" than existing technology). I'm not completely sure how higher energy density can result in faster charging times, but maybe it has to do with the materials used and not the energy density directly.

    Group14 plans to open a factory in Moses Lake, Wash. in the first quarter of 2025 with annual capacity for 4,000 tons of its nanostructured silicon-carbon material, called SCC55. That black powder could supply 20 gigawatt hours of cells, enough to power 100,000 to 200,000 EVs [annually], or millions of consumer devices like phones.

    More such factories have to be opened to produce enough batteries for a full-electric vehicle transition, but this is a great start. Not all vehicles need the same chemistry because different vehicles have different uses by consumers.

    Sionic is claiming the strongest performance of any silicon battery yet. That includes specific energy of at least 330 watt-hours per kilogram, a volumetric density of at least 842 watt-hours per liter, and a proven range of up to 1,200 cycles in 4 to 10 ampere-hour cell formats. By comparison, a teardown of Tesla’s top-performing, nickel-rich 4680 cell suggested specific energy ranging from 272 to 296 Wh/kg, with a volumetric density of 716 Wh/L.

    This should be economical to implement using existing manufacturing pipelines:

    Critically, Group 14’s material and Sionic’s battery platform are designed for seamless “drop-in” production in existing lithium-ion facilities. “That brings the least amount of disruption, at the lowest cost, with a fast path to commercialization,” Williams said.

    People quoted in the article claim that silicon batteries are going to completely replace lithium-ion batteries. We'll see!

    6 votes
    1. [2]
      vord
      Link Parent
      Current "best" charging times are on the order of 15 minutes, so the article is correct there. I suspect your guess is correct; that this is two unrelated possibilities clustered together.

      Current "best" charging times are on the order of 15 minutes, so the article is correct there. I suspect your guess is correct; that this is two unrelated possibilities clustered together.

      3 votes
      1. SunSpotter
        Link Parent
        It’s honestly a hard statement to evaluate at face value because there are so many different EV battery packs out there. But yeah, if we assume market average battery size, 800ish volts and...

        It’s honestly a hard statement to evaluate at face value because there are so many different EV battery packs out there. But yeah, if we assume market average battery size, 800ish volts and standard battery materials then 15ish minutes is about right for the current cutting edge.

        1 vote
    2. [3]
      PuddleOfKittens
      (edited )
      Link Parent
      No, they're going to completely replace the anodes in the lithium-ion batteries. It's phrased incredibly poorly. Broadly speaking, there are three parts of the battery: The cathode, the anode, and...

      People quoted in the article claim that silicon batteries are going to completely replace lithium-ion batteries. We'll see!

      No, they're going to completely replace the anodes in the lithium-ion batteries. It's phrased incredibly poorly.

      Broadly speaking, there are three parts of the battery: The cathode, the anode, and the electrolyte in the middle of the two. It's sort of like a lead-acid battery, where the cathode and anode are the dissimilar metal prongs, and the electrolyte is the acid. Lithium goes in the electrolyte (and theoretically in the cathode in future, but that's another discussion).

      The anode is usually graphite, but ideally would be silicon (which has better numbers), except silicon has a habit of expanding and contracting massively, which rips the battery apart and has made it unusable until recently, where we have some bits of silicon included in the (graphite) anode. Like, 20% silicon.

      Sionic isn't doing anything unexpected, although they possibly are jumping the gun a little.

      I'm not completely sure how higher energy density can result in faster charging times, but maybe it has to do with the materials used and not the energy density directly.

      AIUI the silicon provides 5x the throughput, so theoretically the silicon can be 1/5th the size/weight of an equivalent graphite anode while achieving the same end result. Or alternatively, keep it the same size and have higher energy throughput, which means faster charging and higher wattage output (assuming the anode is the bottleneck, although I have no idea if it is).

      Honestly, I'm not sure what the benefit of energy density even is with cars, I think lower weight is far more directly useful than lower volume. Maybe lower volume permits a slightly smaller frame and thus lower weight and better aerodynamics? Batteries are just a tiny proportion of the car's weight volume. I suppose lower volume would permit more space to be used for airflow and cooling.

      2 votes
      1. [2]
        Nazarie
        Link Parent
        This statement felt incorrect so I checked the Tesla Model Y. It's got a curb weight of 1998kg and a battery weight of 771kg (according to Google). That's ~38%, which I would not classify as...

        Batteries are just a tiny proportion of the car's weight

        This statement felt incorrect so I checked the Tesla Model Y. It's got a curb weight of 1998kg and a battery weight of 771kg (according to Google). That's ~38%, which I would not classify as "tiny".

        That being said, based on the rest of your statement I see you realize batteries are heavy and lowering that weight is a good target. I agree fully. But I happen to think lowering charge times drastically is a much more important target. Today, charging a BEV is an event unlike refilling an ICE. If we can get BEVs to recharge almost as fast as an ICE, it increases the ease of adoption in a broader segment. Range is quickly approaching the ICE average already. Even though most people don't need that range very often, they still insist on having it available. Obviously, this is just my personal opinion as an observer.

        5 votes
        1. PuddleOfKittens
          Link Parent
          Fuck, I meant volume. Batteries are a tiny proportion of EVs' volume. Typo. Fixed.

          Fuck, I meant volume. Batteries are a tiny proportion of EVs' volume. Typo. Fixed.