A Supercapacitor From Mushrooms

The supercapacitor is an extremely promising energy storage technology, and though they have yet to reach parity with the best batteries in terms of energy density, offers considerable promise for a future of safe and affordable energy storage. Perhaps best of all from our point of view, they are surprisingly simple to make. A practical supercapacitor can be made on the bench by almost anyone, as the ever-resourceful [Robert Murray-Smith] demonstrates using mushrooms as his feedstock.

The idea of a supercapacitor is to replace the flat plate on the simple capacitor from your physics textbook with one that has as large a surface area as possible for charge to accumulate on. In this case the surface is formed from organic charcoal, a substance which retains something of the microscopic structure of whatever it was made from. Mushrooms are a good feedstock, because their mycelium structure has a naturally huge surface area. He takes us in the video below the break through the process of carbonizing them, much easier when you have a handy kiln than trying the charcoal-burner method, and then grinds them to a powder before applying them as a paste with a binder to a piece of graphite foil. With two of these electrodes and a piece of paper towel as a dielectric, he demonstrates a simple benchtop supercapacitor running a small electric motor for a surprisingly longer time than we expected.

We’d like to see further work on home made supercapacitors, as we believe they have immense potential as well as storing the stuff. Meanwhile, this is by no means the most unexpected supercapacitor material we’ve seen.

Mushroom image: Devika0067, CC BY-SA 4.0.

27 thoughts on “A Supercapacitor From Mushrooms

  1. Stop promoting this YT, in the early days he’s built DYI ultracaps and tried to market and/or sell them or get investment money. Then he deletes certain videos that could bite him later on.

    1. Yeah, he’s a scammer but he’s very good at what he does. Careful though, pointing this out will get your posts deleted. HaD loves this guy, despite the fact that he intentionally leaves out any quantitative data and leans heavily on “wow this (tiny) motor/LED/etc. runs for a long time” to get clicks and money from clueless nerds. For example in this video, why not face the power supply towards the camera? Inquiring minds want to know.

      1. You can sort of piece together his work through extended research of multiple videos. One example is his ‘bulletproof’ graphene doped polymer. In the video showing his results he talks about doping ABS or other thermoplastics but if you watch his previous video the polymer in question is casein (purified from milk) which is then heat pressed. Though he admitted it would take a substantially thicker plate than he showed to stop 9mm, and he only tested with .22lr. I could not speak to him as a contractor of third-party R&D firm, which seems to be what he promotes mainly.

      2. To be fair, he would be doing just fine if he’d pitch things as a fun demonstration for students or something. By all appearances, his stuff generally does demonstrate a concept correctly, and sometimes it’s a concept that may be worth looking into at least in a DIY niche or something.

        The problem is all about the quantitative part, where he typically acts like there’s not massive inherent reasons why the thing he’s demonstrating can’t be improved to the point of actually replacing any part of current practices at scale. Like using spoons as a wind generator.

        He might be able to make decent money if he was more honest. In his shoes, I’d try writing up instructions to go with the videos; I’d have enjoyed seeing some of these as demos or labs in school and the schools do pay somewhat for access to educational materials.

        1. I commented on his channel back when he (improperly) tested his white paint which cooled a surface supposedly as well as the MUCH more difficult to make paint of an excellent, scientifically accurate channel whose name I don’t recall at the moment. He used a handheld IR thermometer for his measurements while the other channel used a thermal camera. I explained measurement errors due to surface emissivity to him. I didn’t go back to see if the comment was deleted or if he replied to it.

          BTW, you can tell if you’ve been shadow banned by looking for your comment while NOT logged onto YouTube. It won’t be visible then, but will be when you’re logged in.

          1. The one you can’t remember may have been Tech ingredients or NightHawkInLight, both of whom have covered the subject pretty well and are worth checking out.

      3. He’s not a scammer. A scam is when you pay money and you get nothing in return or you get something useless or entirely different and less valuable than what you agreed to. He is not doing that. He worked in the industrial battery global market for a huge mega corporation and he’s highly qualified to start a small battery factory. If you don’t want to invest into a small battery manufacturer then do not. If you think that is not a good investment, then don’t invest. It’s quite simple.

      1. What I’m saying is that he could do without the mushroom baking – to use the activated charcoal directly. And part of the activated charcoal should have burned if it was to protect the mushrooms from burning.
        Now you’re going to say that the energy is not wasted, but used to warm up the house.

    1. I believe the idea is that the mushroom produces carbon with a higher surface area, making it more effective at holding charge. As a mushroom farmer, didn’t expect to see them here!

      1. Doubt it, activated charcoal has been processed to greatly increase it’s surface area. That’s what makes it ‘activated’.

        Activated charcoal is the standard material for supercaps. Sometimes ‘doped’ with various trace elements.

    2. One wouldn’t need activated carbon to prevent oxidation of their carbonized mushrooms. Truth be told, the vast majority of the activated carbon Rob used was not sacrificed, oxidized to CO2, and is still useful. Reguardless, unactivated charcoal would have worked just as well at preventing oxidation during carbonization of the mushrooms, and would have been cheaper.

      Activated carbon is nothing more than carbon with a bunch of holes put in it that provide a greater surface area. Cody’s Labs (youtube channel) did it at home by steam activation. alternatly charcoal may be chemically activated at high temperatures. If your interested Cody also had a video showing how to test the amount of “activation” by how well chacoal samples absorbe a chemical.

      Being activated charcoal it’s just putting small holes in the carbon, and mycelium starts off with a structure that once is carbonated, might perform comparable, or maybe just well enough, to commercial activated charcoal, but could instead be produced in a home retort instead.

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