DIY Super capacitors made out of Graphene

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DIY Super capacitors made out of Graphene

Postby nabilt » Wed Mar 21, 2012 11:18 am

There has been a video going around from researchers at UCLA about building super capacitors using a Lightscribe DVD writer and graphite oxide (GO), which I think looks really amazing and am interested in reproducing. I figured others might be as well so here is what I know so far.

UCLA Video
http://www.youtube.com/watch?v=_oEFwyoWKXo

Similar older video from Rice University that used a CO2 laser
http://www.youtube.com/watch?v=3O4YV0mrkfQ

Full Paper
http://hackadaycom.files.wordpress.com/2012/03/el-kady-som.pdf

Summary paper
http://hackadaycom.files.wordpress.com/2012/03/laser-scribing-of-high-performance-and-flexible-graphene-based-electrochemical-capacitors.pdf

Popular method of producing GO - Modified Hummer's method (pay wall)
http://pubs.acs.org/doi/abs/10.1021/nn1006368

Paper I found on google about producing GO. Appears similar to Hummer's method.
http://www.rsc.org/suppdata/nr/c1/c1nr10549c/c1nr10549c.pdf

I'm not a chemist so take everything with a huge grain of salt.

Producing GO
Googling around it appears GO is cheap to produce, but I can't seem to find any suppliers. It is produced from highly pure graphite (carbon atoms structure in a lattice - stuff commonly known as pencil lead) using Hummer's method (linked above). I haven't paid for the article yet, but the abstract says, "We have found that excluding the NaNO3, increasing the amount of KMnO4, and performing the reaction in a 9:1 mixture of H2SO4/H3PO4 improves the efficiency of the oxidation process". The last article linked above says, "9:1 mixture of H2SO4 (95%) / H3PO4 (85%) [360:40 mL] was added to a mixture of graphite powder (3.0 g, 1 wt. equiv.) and KMnO4 (18.0 g; 6 wt. equiv)".

After isolating the solid GO from the liquid it is dried and neutralized to produce a powder. From there it is mixed with water and vacuum filtered or cast into a mold using a centrifuge. The result is what we see in the videos.

Producing Graphene from GO (The cool part)
According to Wikipedia, "graphene is an isolated atomic plane of graphite". It is super conductive, 97% transparent and flexible. There is hope that this relatively new material can be used to create flexible circuits and high frequency transistors. IBM was successful in creating transistors with a 100GHz switching frequency. Researchers at Cornel have shown devices can be created by printing graphene using an inkjet printer http://en.wikipedia.org/wiki/Graphene#Graphene_transistors.

There are many methods of producing graphene. One method uses scotch tape to peel layers off graphite. [url]http://www.youtube.com/watch?v=ehvksWx3AJQ&feature=related[\url]. Recently the most interesting method is to use lasers to strip oxygen atoms from GO, which is what the researchers did in the video above. Cheap and simple.

Making a supercapacitor
I'm still reading about their construction, but it appears the researchers use either an electrolyte gel or other type of high performance insulator. In one example they used Celgaurd 3501 http://www.ldcgm.com/Celgard/CELGARD-4550.pdf. Both types don't look like they are easy to find or make.

Conclusion
If you have access to GO sheets then the project looks doable. It seems you might not get high energy and power density unless you use the aqueous electrolyte or ionic liquid, which I'm not sure is readily available. Otherwise, making GO at home does not seems feasible because of the high concentration of acids involved.
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Re: DIY Super capacitors made out of Graphene

Postby SiskinEDGE » Thu Mar 29, 2012 9:58 am

anything non conducting can be used as an eletrolyte but you want something that is as thin as posible. the easiest way is take all of these layers of graphene on plastic facing the same way and then compress them as much as posible, useing the plastic that you made the graphene on as the eletrolyte for the capcitor itself. theres no way you can remove the graphene from the film so why not use it as part of your design and reduce cost and weight. also there was a youtube video about useing a camera flash to turn GO into graphene, which is easer, cheaper and faster than useing lightscribe.
v=dKT2vzfUuEs - camera flash graphene

the ideal eletrolyte would react with the graphene like the way that aluminion oxcide forms on aluminion, so it would quickly form a thin layer that protects the lower layers from oxidation. or charge the eletrode and layer on a thin layer of charged paint or something to make a very thin layer.

[EDIT] - Graphene oxcide is an insulator, what if there were alternating layers of graphene oxcide and graphene. deposite one layer of graphene on, add on the graphene oxcide to the plate while charged and then sandwich another graphene layer on top.
Last edited by SiskinEDGE on Thu Mar 29, 2012 12:41 pm, edited 1 time in total.
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Re: DIY Super capacitors made out of Graphene

Postby nabilt » Thu Mar 29, 2012 10:41 am

Good idea about using the substrate as the insulator. That is probably the first thing anyone should try if they attempt this project.

Haven't read the paper from the researchers using the camera flash, but what I've read from other papers is the resulting graphene is not as super conducting as the laser method.
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Re: DIY Super capacitors made out of Graphene

Postby slavkosky » Sat Jun 04, 2016 6:57 pm

I wonder what combining the two methods (Laser/Camera Flash) would do? Could be a good way to "fill in" the spaces (if there are any) between each laser path (since the laser is focused and can only print so big/small per pass. I'm thinking of it like a vinyl record with grooves.
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Re: DIY Super capacitors made out of Graphene

Postby slavkosky » Sat Jun 04, 2016 7:13 pm

Also, I'm trying the laser method on an aluminum foil substrate (instead of PET), as it's much cheaper to buy than PET Laser-Printer Transparency Sheets, and it's already in my kitchen ;)

If anyone else can help bring this thread back to life I'm now following it.

If you're using a different method of bulk Graphene production (my purpose is for supercapacitors), I'm all ears!
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Re: DIY Super capacitors made out of Graphene

Postby slavkosky » Wed Jun 08, 2016 6:25 pm

So, the Aluminum foil substrate was a bad idea. When I tried to pull it off of the Lightscribe disk, the foil ripped and creased, even taking some of the disk coating with it. What a mess. It seems that PET(while probably not the only choice) may be the best choice for this process. It bends but doesn't crease, and has a much higher melting point than Polypropylene, making it ideal for this method. I just wish it was more widely available at brick & mortar stores.

If anyone knows where to source this stuff, let me know!
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