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posted by janrinok on Friday May 29 2015, @01:56PM   Printer-friendly
from the all-charged-up dept.

Chemists at the Waterloo University have discovered the key reaction that takes place in sodium-air batteries that could pave the way for development of the so-called holy grail of electrochemical energy storage.

Unlike the traditional solid-state battery design, a metal-oxygen battery uses a gas cathode that takes oxygen and combines it with a metal such as sodium or lithium to form a metal oxide, storing electrons in the process. Applying an electric current reverses the reaction and reverts the metal to its original form.

In the case of the sodium-oxygen cell, the proton phase catalyst transfers the newly formed sodium superoxide (NaO2) entities to solution where they nucleate into well-defined nanocrystals to grow the discharge product as micron-sized cubes. The dimensions of the initially formed NaO2 are critical; theoretical calculations from a group at MIT has separately shown that NaO2 is energetically preferred over sodium peroxide, Na2O2 at the nanoscale. When the battery is recharged, these NaO2 cubes readily dissociate, with the reverse reaction facilitated once again by the proton phase catalyst.

Chemistry says that the proton phase catalyst could work similarly with lithium-oxygen. However, the lithium superoxide (LiO2) entities are too unstable and convert immediately to lithium peroxide (Li2O2). Once Li2O2 forms, the catalyst cannot facilitate the reverse reaction, as the forward and reverse reactions are no longer the same. So, in order to achieve progress on lithium-oxygen systems, researchers need to find an additional redox mediator to charge the cell efficiently.

Another battery technology "only a few years from the market"?


[Editor's Comment: Original Submission]

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  • (Score: 3, Insightful) by LoRdTAW on Friday May 29 2015, @02:12PM

    by LoRdTAW (3755) on Friday May 29 2015, @02:12PM (#189667) Journal

    Do not submerge battery in water!

    • (Score: 2) by Immerman on Friday May 29 2015, @06:28PM

      by Immerman (3985) on Friday May 29 2015, @06:28PM (#189769)

      Hmm. Actually IIRC sodium is usually stored immersed in oil to prevent reaction with ambient water vapor. And one of the big benefits of oxygen batteries is that they can "breath" ambient air, dramatically reducing their mass. I can only assume that's not an option in this case...

      • (Score: 2) by LoRdTAW on Friday May 29 2015, @06:48PM

        by LoRdTAW (3755) on Friday May 29 2015, @06:48PM (#189782) Journal

        I was thinking the battery would be hermetically sealed with a either a pure oxygen mixture or a mixture of oxygen and some other non-reactive gas(es). Otherwise the sodium or lithium would react with the ambient moisture and ruin the battery or start a fire.

        • (Score: 2) by RedBear on Friday May 29 2015, @11:13PM

          by RedBear (1734) on Friday May 29 2015, @11:13PM (#189889)

          Funny story, and largely on-topic. I was in chemistry class in high school once upon a time. We were in the lab, where the chemistry teacher had just recently finished giving us all the important lecture about Not Doing Anything Stupid whenever one is in the chemistry lab, and how Doing Anything Stupid in the chemistry lab will get one permanently ejected from his chemistry class with no possibility of appeal.

          I had no intention of Doing Anything Stupid. Only someone quite stupid would Do Something Stupid in a chemistry lab. I was not Stupid, like those Stupid kids always horsing around and not paying attention to the teacher. I was Smart. I payed attention. And Read lots of Books.

          That day the teacher was demonstrating the reaction between sodium and water, by removing a small chunk of pure sodium stored in a jar of oil and cutting off a much tinier chunk, weighing maybe a couple of grams, to drop in another jar full of water. Even that tiny piece of sodium made a fairly loud bang after it sizzled around on the top of the water for a few seconds. A slightly larger piece made any even bigger bang. It was cool.

          At some point during the preparations I had gotten bored and was checking out whatever was sitting on the small raised counter that separated two typical lab counters. Each side had a sink and a couple of bunsen burner gas outlets. On top of the separator there was a short beaker containing a few dull gray, thin metal strips. They were obviously not steel, and if bent would stay bent. I assumed them to be aluminum, possibly magnesium, but probably aluminum. For some reason it seemed like a perfectly safe and good idea to take a plastic pipette that was also sitting on the counter, take some water from the sink, and dribble the water onto the thin metal strips in the beaker.

          A few minutes later, as other things are going on, I smell something. Then hear something. Sort of a quiet sizzling sound. Then I notice a whisp of vapor coming from the beaker with the little metal strips in it. When I looked closer, the water droplets on the metal strips were BOILING OFF INTO STEAM.

          I felt a sudden shock. I was not Smart. I was Stupid. Here was Proof, staring me in the face. I had gone and Done Something Stupid in the chemistry lab.

          Fortunately I was in the back of the group and everyone was paying attention to the teacher, so ultimately nobody noticed anything. Since the reaction didn't seem to be getting any worse I just backed away from the area to avoid the fumes and commenced valiantly pretending that I, too, was paying attention and, if asked, would have NO IDEA that anything untoward had just occurred. Needless to say the lesson learned that day was, exactly as the teacher said, when you set foot in a chemistry lab you DO NOT futz with anything except exactly what the chemistry teacher tells you to futz with. Because those strips of harmless aluminum in a beaker? Yeah, they might not be aluminum, and they might not be harmless.

          Years later I remembered this incident and after some googling finally figured out that those strips must have been either pure lithium or a lithium alloy with enough lithium to react that way and boil off the water. But at the time I had thought that sodium was the only metal that reacts with water, and I knew it wasn't sodium because A) I'd just watched the teacher slice through a chunk of pure sodium with a pocket knife as if it was a cold stick of butter, and B) he'd just gotten finished explaining that sodium is so reactive it has to be stored in oil. So when those little metal strips stored openly and casually in a beaker on the top of a lab bench started reacting with tap water it was a real "WTF?" moment.

          Sadly, in that whole high school chemistry class I only remember us entering that lab twice. Once for the sodium demonstration and once to make a super-saturated solution of sugar water so we could drop a grain of sugar in it and watch it crystallize. Yes, we were doing things that students in most other countries did in grade school. That chemistry class was remarkably boring and disappointing, like most of what I recall from my public school years. I understood far more about chemistry from just readding the first few pages of "Asimov on Chemistry" than I ever learned in a year of high school chemistry class. Really sad.

          • (Score: 1) by anubi on Saturday May 30 2015, @02:39AM

            by anubi (2828) on Saturday May 30 2015, @02:39AM (#189948) Journal

            Ok.. I had a similar run.

            In my first two years of college, taken at a community college, I worked as the chemistry lab assistant.

            It was the end of the semester. A bunch of organic chemistry students poured their beakers right down the drain.

            Some of those beakers had little strips of potassium in them to keep the solvent completely anhydrous.

            When poured down the drain, they reacted with water present in the drain to form hydrogen.

            Which made a rather loud "thoomp" in a couple of minutes, with water coming out of all drains quite forcibly.

            But that wasn't the hard part. That was pretty easy to clean up.

            The biggest mess, by far, was in the bathroom stalls.

            Jets of raw sewage shot three to four feet in the air from each toilet and urinal, thoroughly dousing everyone who happened to be sitting on the throne or standing at the urinal.

            Apparently, there was no damage to the plumbing, as the reaction took several seconds, but there was a significant amount of laundry to be done.

            The story lived on as long as I was there, passed from one generation of lab assistants to the next.

            This story was told to me by the assistant I relieved as he went on to higher level classes, and I told it to the guy who relieved me.

            The professor claimed it really happened.
             
            Personally, I would love to have had pictures of the aftermath.
             
            Especially toilet pics.

            --
            "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
  • (Score: 4, Insightful) by Tork on Friday May 29 2015, @03:26PM

    by Tork (3914) Subscriber Badge on Friday May 29 2015, @03:26PM (#189699)

    Another battery technology "only a few years from the market"?

    "Here's an article for you and here's why you shouldn't give a shit."

    --
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    • (Score: 4, Insightful) by kaganar on Friday May 29 2015, @04:00PM

      by kaganar (605) on Friday May 29 2015, @04:00PM (#189715)
      I'm glad the editor decided to leave that question in because it was the first thing on my mind and we could jump straight to constructive evaluations instead of seeing 5 duplicate posts asking the same thing. But now we're bashing the editor, instead.
      • (Score: 0) by Anonymous Coward on Friday May 29 2015, @07:43PM

        by Anonymous Coward on Friday May 29 2015, @07:43PM (#189808)

        > But now we're bashing the editor, instead.

        Some people have nothing to contribute to the discussion other than contrariness but they still feel the need to contribute.

    • (Score: 2) by takyon on Friday May 29 2015, @08:10PM

      by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Friday May 29 2015, @08:10PM (#189823) Journal

      The truth hurts.

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      [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
      • (Score: 2) by Tork on Friday May 29 2015, @08:33PM

        by Tork (3914) Subscriber Badge on Friday May 29 2015, @08:33PM (#189833)

        The truth hurts.

        ... Yeah, because everybody knows I'm a sodium-air fanboy.

        Seriously, though, where did that even come from?

        --
        🏳️‍🌈 Proud Ally 🏳️‍🌈
    • (Score: 2) by Gravis on Saturday May 30 2015, @02:05AM

      by Gravis (4596) on Saturday May 30 2015, @02:05AM (#189937)

      read the original submission, it includes the "Another battery technology..." comment, the editor didn't explicitly add it.

      • (Score: 2) by Tork on Saturday May 30 2015, @02:29AM

        by Tork (3914) Subscriber Badge on Saturday May 30 2015, @02:29AM (#189945)
        My bad.
        --
        🏳️‍🌈 Proud Ally 🏳️‍🌈
  • (Score: 3, Informative) by AnonTechie on Friday May 29 2015, @08:35PM

    by AnonTechie (2275) on Friday May 29 2015, @08:35PM (#189834) Journal

    New 'designer carbon' boosts battery performance

    Tests were also conducted on lithium-sulfur batteries, a promising technology with a serious flaw: When lithium and sulfur react, they produce molecules of lithium polysulfide, which can leak from the electrode into the electrolyte and cause the battery to fail.

    The Stanford team discovered that electrodes made with designer carbon can trap those pesky polysulfides and improve the battery's performance.

    "We can easily design electrodes with very small pores that allow lithium ions to diffuse through the carbon but prevent the polysulfides from leaching out," Bao said. "Our designer carbon is simple to make, relatively cheap and meets all of the critical requirements for high-performance electrodes."

    http://phys.org/news/2015-05-carbon-boosts-battery.html [phys.org]

    --
    Albert Einstein - "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."