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Graphene based Supercapacitors

Discussion in 'General Electronics Discussion' started by TehBen, Apr 30, 2013.

  1. TehBen

    TehBen

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    Apr 30, 2013
    Hi all, I'm currently writing an article about the benefits of using graphene in supercapacitors, but being an electronics idiot, I am a bit confused as to where to start.

    I've been looking for figures relating to how using graphene electrodes compares to using activated carbon lined electrodes (I assume this is correct), but a lot of the data I have found contradicts itself, and finding direct comparisons is nigh-on impossible.

    The conclusion I have come to is that while graphene has a high surface area and it has a high potential, it is not currently optimized for use in super-caps, or it has not been proven with statistical data to be an improvement.

    Some have suggested that 550 F/g is possible with graphene-based supercaps (the Kaner publication), but also I have read that some commercially available supercaps are already able to hold between 200-400 F/g using activated carbon, which is pretty impressive in itself.

    But compared to using batteries, this isn't that great, relatively speaking; it's just the charge/discharge rate that is impressive. But the number of supercaps needed to power a vehicle similar to the Tesla, for example, would be vast, and end up weighing more than currently used batteries. Is that right?

    Here is an example:
    "Researchers in the US have made a graphene-based supercapacitor that can store as much energy per unit mass as nickel metal hydride batteries – but unlike batteries, it can be charged or discharged in just minutes or even seconds."
    It just seems very vague. Is this meant to be comparing specific energy?

    Sorry for my ignorance, like I said, I'm a complete novice and am just doing some research for a paper I am writing.
     
  2. BobK

    BobK

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    Jan 5, 2010
    I don't find that vague at all. It is saying that researchers (not commercial products) have built supercaps that can store as much energy per gram as NiMH batteries. Which is quite an acommplishment. The Tesla, on the other hand uses Lithium Ion batteries which store about 50% more than NiMH.

    Bob
     
  3. TehBen

    TehBen

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    Apr 30, 2013
    I see, thanks. So that simply means that to use these supercapacitors to power something like the Tesla, you must have 50% more in terms of unit weight, plus then overcome the other problems such as energy loss.

    What kind of level of F/g are Lithium Ion batteries?
    Do graphene supercaps have the potential to compare against the energy density levels of Lithium Ion batteries?
     
  4. BobK

    BobK

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    Jan 5, 2010
  5. quantumtangles

    quantumtangles

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    Dec 19, 2012
    No articles should be written about capacitors (even graphene supercaps) unless the author has seen the famous and amusing Afrotechmods video entitled Fun with Ultracapacitors.



    Watch out for the reference to Canadian coinage at 1:20.

    On a more serious note (though the video is wonderfully informative as well as amusing), UCLA academics have discovered a way to burn Graphene based components directing using the disc drive of an ordinary computer. I cannot overstate the importance of this. As I understand it, they made (printed) graphene transistors using the disk drive of an ordinary computer.

    This may yet enable graphene supercaps to be made at home (perhaps using a combination of next gen makerbots and better adapted DVD burners...+ cans of 'spray and pray' graphene..which I find an intriguing prospect.

    A post-UCLA pioneer has a go in the following video.



    But for the real science, see 'Graphene based Supercapacitors'

     
    Last edited: May 1, 2013
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Very interesting stuff.

    Balancing charge in a bank of supercapacitors is an interesting problem and once you can do that they become even more useful. Doing so in a non-dissipative manner is even better :)

    This and this and this are interesting reads.
     
  7. TehBen

    TehBen

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    Apr 30, 2013
    That's great, thanks for the extra reading/watching material!
     
  8. TehBen

    TehBen

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    Apr 30, 2013
    :cool::cool:
     
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