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Rare Form of Sulfur Offers a Key To Triple-Capacity EV Batteries (newatlas.com) 60

Engineers at Drexel University have made a breakthrough they say takes [lithium-sulfur batteries] closer to commercial use, by leveraging a rare chemical phase of sulfur to prevent damaging chemical reactions. New Atlas reports: [T]here is one problem that scientists keep running into, which is the formation of chemical compounds called polysulfides. As the battery operates, these make their way into the electrolyte -- the solution that carries the charge back and forth between the anode and cathode -- where they trigger chemical reactions that compromise the battery's capacity and lifespan. Scientists have had some success swapping out the carbonate electrolyte for an ether electrolyte, which doesn't react with the polysulfides. But this poses other problems, as the ether electrolyte itself is highly volatile and contains components with low boiling points, meaning the battery could quickly fail or meltdown if warmed above room temperature.

The chemical engineers at Drexel University have been working on another solution and it starts with the design of a new cathode, which can work with the carbonate electrolytes already in commercial use. This cathode is made from carbon nanofibers and had already been shown to slow the movement of polysulfides in an ether electrolyte. But making it work with a carbonate electrolyte involved some experimentation. The scientists attempted to confine the sulfur in the carbon nanofiber mesh to prevent the dangerous chemical reactions using a technique called vapor disposition. This didn't quite have the desired effect, but as it turned out, actually crystallized the sulfur in an unexpected way and turned it into something called monoclinic gamma-phase sulfur, a slightly altered form of the element. This chemical phase of sulfur had only been produced at high temperatures in the lab or observed in oil wells in nature. Conveniently for the scientists, it is not reactive with the carbonate electrolyte, thereby removing the risk of polysulfide formation.

The cathode remained stable across a year of testing and 4,000 charge-discharge cycles, which the scientists say is equivalent to 10 years of regular use. The prototype battery the team made featuring this cathode offered triple the capacity of a standard lithium-ion battery, paving the way for more environmentally friendly batteries that allow electric vehicles to travel much farther on each charge.
The research was published in the journal Communications Chemistry.
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Rare Form of Sulfur Offers a Key To Triple-Capacity EV Batteries

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  • Battery capacity (Score:4, Insightful)

    by serviscope_minor ( 664417 ) on Saturday February 12, 2022 @05:44AM (#62261673) Journal

    Whenever we hear about new research about battery capacity, there are always gales of complaints. I think these stem from there never being a huge step change, but come on, look at modern batteries! They have come on amazingly far in the last 20 years. They are much lighter, have much higher discharge rates and recharge rates, much better capacity and we have the tech to make them last even when they get a hammering.

    All of these improvements add up. My special offer Makita drill would be alien technology on 2002, and today it's not just in existence but eminently affordable.

    The steady stream of improvements make a difference.

  • by backslashdot ( 95548 ) on Saturday February 12, 2022 @05:48AM (#62261683)

    How many Watt hours per kilogram does it have? Not interested in mah/g if the voltage is low.

  • Thank you for our daily yet-another-super-battery report.
  • by Futurepower(R) ( 558542 ) on Saturday February 12, 2022 @07:21AM (#62261745) Homepage
    Quote from the story -- Cheaper batteries with more energy:

    "Lithium-sulfur batteries hold a lot of promise when it comes to energy storage, and not just because sulfur is abundant and less problematic to source than the cobalt, manganese and nickel used in today's batteries. They may offer some significant performance gains, too, with the potential to store several times the energy of today's lithium-ion batteries. But there is one problem that scientists keep running into, which is the formation of chemical compounds called polysulfides."
    • If Lithium-Sulfur batteries are far cheaper and have much more energy, people who need car engine maintenance can replace the gas engine with an electric motor, and the Lithium-Sulfur batteries.

      The maintenance expense for an electric motor is FAR less. No need for oil changes and spark plug replacements. No need for piston ring replacements.

      If we develop healthy ways to generate more electricity, that would reduce the pollution.

      At present it is not healthy to live in a city, because city dwellers a
      • Re: (Score:2, Funny)

        by Aighearach ( 97333 )

        If Lithium-Sulfur batteries are far cheaper and have much more energy, people who need car engine maintenance can replace the gas engine with an electric motor, and the Lithium-Sulfur batteries.

        Plus the word "sulfur" will help to salve the egos of the ugga-wugga crowd. "It runs on devil farts!"

  • by GlobalEcho ( 26240 ) on Saturday February 12, 2022 @08:50AM (#62261853)

    The article from Drexel University (where the research was done) is better, and not so laden with ads:

    https://drexel.edu/now/archive... [drexel.edu]

    • by Klaxton ( 609696 ) on Saturday February 12, 2022 @10:20AM (#62261973)

      Thanks, and here's a link to the actual paper in Nature which has loads of details;
      https://www.nature.com/article... [nature.com]

      The -monoclinic phase of sulfur discovery is interesting but it looks a very long way from commercialization. They make the compound in an autoclave which "consisted of a sulfur reservoir at the bottom and a perforated disk for placing electrodes at the top. After 24h the autoclave was cooled to room temperature slowly in a span of 6–8h."

      And "we utilized the scraped residual material deposited on the top wall of our autoclave for cathode fabrication".

      So a lot of mass manufacturing challenges, you won't be making gigawatt hours of this any time soon.

      • US patent application Application [uspto.gov] . Click on the blue Images button top center, then Full Document: Full Pages left side for PDF. Perspective on the apparatus drawing is about as good as the Mad Magazine "poiuyt" illusion.
      • by Junta ( 36770 )

        Yeah, I hope they figure it out, but it sounds like they lucked into something they don't quite understand yet. So the possible outcomes are:
        -With more knowledge, we discover the material is not viable in the real world even if you can make it (time-based degradation, atmospheric temperature variations impacting it, something)
        -It carries on as-is, in which case the process to manufacture this form of sulfur remains highly impractical
        -Focused research in this area uncovers a more practical manufacturing pro

      • I have used very similarly deposited material. It was not Asimov's resublimated thiotimolene, but it actually was to become resublimated tetrathiafulvalene.
  • by Powercntrl ( 458442 ) on Saturday February 12, 2022 @03:04PM (#62262511) Homepage

    I’ve owned plenty of lithium chemistry batteries that died of old age before they were anywhere near their rated cycle life. It seems every time there’s an article about BEV batteries, they always rate the lifespan in miles or charge cycles, completely ignoring the fact that batteries also degrade with age.

    The average age of a car in the USA is approximately 12 years old. A battery that lasts only 10 years isn’t going to cut it.

    • by Klaxton ( 609696 )

      What makes you think the batteries degrade with age?

      • This https://www.protoolreviews.com... [protoolreviews.com]

        and https://www.large.net/news/88u... [large.net]

        Tesla has arguably the best battery management, but you need to keep your Tesla automobile plugged in. That scene in Woody Allen's "Sleeper" where he and Diane Keaton find an abandoned VW Beetle and they start it right up is not going to happen with an electric car stored in a barn for decades let alone just kept in a garage unplugged for 6 months.

        Long-range lithium-battery electric cars haven't been around long enough to fin

        • A gasoline car sitting in a barn for a year isn't going to start either; the gas will have gone to shit.

          Diesel does have a longer shelf life, but not decades.

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