DIY graphene high capacity supercapacitors -use a DVD writer
- Thread starter MitchJi
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liveforphysics
100 TW
Capacitors are so worthless for energy storage. Even if you made them have 10x energy density of the best existing supercaps, it's still worthless for energy storage.
The resistance is crap too. You can get more power from a given volume or mass of nano-tech's vs the best supercaps.
In practice, charge rates are all ready only limited by chargers, having a battery that could charge in a nano-second vs one capable of charging in 5minutes doesn't make any difference in the charge rate you're going to see in real life. I have 20,000w charge systems that run on 440v 3p power, and still the charger is the slower than the batteries ability to take charge.
Most ultra caps also do a bunch of dumb things like bleed empty over the course of a week just sitting, require balancing systems like batteries, and storing the lower portion of the energy they carry at a voltage that makes it largely useless to access for transportation applications.
The resistance is crap too. You can get more power from a given volume or mass of nano-tech's vs the best supercaps.
In practice, charge rates are all ready only limited by chargers, having a battery that could charge in a nano-second vs one capable of charging in 5minutes doesn't make any difference in the charge rate you're going to see in real life. I have 20,000w charge systems that run on 440v 3p power, and still the charger is the slower than the batteries ability to take charge.
Most ultra caps also do a bunch of dumb things like bleed empty over the course of a week just sitting, require balancing systems like batteries, and storing the lower portion of the energy they carry at a voltage that makes it largely useless to access for transportation applications.
The video says they have the same energy density as current battery tech (not sure which battery tech). And aparently graphine is the best conductor in the world. But the way its mesured might be a part of how its rated. Just because it has x resistance per mass doesnt mean it will be better then copper.liveforphysics said:
hillzofvalp
100 kW
Your charger could be another bank of super caps that are always being topped by say a 2kW household compatible psu. You wouldn't need 1500A psu...
liveforphysics
100 TW
Arlo1 said:
I hate to be skeptical, but I've seen this sort of talk for the last 10 years now, how ultra-caps are going to gain a useful amount of energy density through various means, and still we have capacitors that just remain about 100x off of where they need to go to be useful for vehicle energy storage.
I would love to see it come true, and love to see batteries replaced by caps that can store and retain a meaningful amount of energy, but I'm not holding my breath at this point.
Lebowski
10 MW
fechter said:
we're not interested in your bowel movements, plus it's not nice to brag
Ultracapacitors would not be the only thing graphene would be handy for. According to some research,
"In widths as narrow as 16 nanometers, graphene has a current carrying capacity approximately a thousand times greater than copper – while providing improved thermal conductivity."
So let's make motor windings out of the stuff. It's dang near superconducting.
If a motor is powered by an ultracapacitor, I think the tires are going to become the weak link.
But WAIT, graphene is super strong and flexible, so we can make tires out of it too.
I'm gonna get me a big can of beans...
"In widths as narrow as 16 nanometers, graphene has a current carrying capacity approximately a thousand times greater than copper – while providing improved thermal conductivity."
So let's make motor windings out of the stuff. It's dang near superconducting.
If a motor is powered by an ultracapacitor, I think the tires are going to become the weak link.
But WAIT, graphene is super strong and flexible, so we can make tires out of it too.
I'm gonna get me a big can of beans...
The voltage on a battery stays nearly constant during discharge. The voltage on a capacitor drops steadily as it discharges.
liveforphysics
100 TW
Arlo1 said:
Caps store an imbalance of electrons from charge plate to charge plate. Ultra-caps (which are greatly different than standard caps) work almost exactly like a lithium ion battery, only with electrons rather than lithium ions.
You can actually make your own ultra-cap by just taking the anodes (the copper foil layers) from lithium batteries apart and stacking them on each other with the seperator from a capacitor and the solvent from the cell you opened. It's a super crummy cap with bad energy density, and if you charge past about 3v it can just arc and blow up, but it can store charge like an ultra-cap. It will have about 1/100th of the energy storage those layers had when paired with an appropriate cathode material, a lithium ion permeable seperator, and some lithium salts added for an ion source to shove ions to intercalate in the cathode rather than just trying to get electrons to stay in the surface carbon anode.
Reality is full of potential
The astonishing claim that graphene can draw on ambient thermal energy to generate electrical current has been attracting scepticism from some materials scientists
http://arxiv.org/abs/1203.0161
Thermoelectrically Pumped Light-Emitting Diodes Operating above Unity Efficiency
http://prl.aps.org/abstract/PRL/v108/i9/e097403
It is actually all related to sound and ultrafluid
The astonishing claim that graphene can draw on ambient thermal energy to generate electrical current has been attracting scepticism from some materials scientists
http://arxiv.org/abs/1203.0161
Thermoelectrically Pumped Light-Emitting Diodes Operating above Unity Efficiency
http://prl.aps.org/abstract/PRL/v108/i9/e097403
It is actually all related to sound and ultrafluid
Lebowski
10 MW
fechter said:
so it's linear versus non-linear ?
whatever
100 kW
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Phosphoric acid is cheap and easy to get, its what rust converter is made of.
One problem solved.......many to go.
Will need some membrane between the graphene also. Possibly the container of the supercap may need to not react with phosphoric acid.
I would think the price of supercaps should plummet if this process eliminates some cost of production. The chinese will be onto it in very short time,
maybe not worth all the headaches of trying to figure out how to make the caps. I suspect there will be numerous technical problems to overcome.
All the time and energy spent trying to make them when possibly in a year or two they will become cheap
I thought the internal resistance of batteries is the limiting factor in charging them, you might be able to store alot of the regen till the supercap is full,but will still take time to deliver it to the battery bank.
Carbon fibre tow is cheap, I'm not sure of its electrical properties ( maybe similar to graphene), there are papers on the net about it, but i've never read them.
One problem solved.......many to go.
Will need some membrane between the graphene also. Possibly the container of the supercap may need to not react with phosphoric acid.
I would think the price of supercaps should plummet if this process eliminates some cost of production. The chinese will be onto it in very short time,
maybe not worth all the headaches of trying to figure out how to make the caps. I suspect there will be numerous technical problems to overcome.
All the time and energy spent trying to make them when possibly in a year or two they will become cheap
I thought the internal resistance of batteries is the limiting factor in charging them, you might be able to store alot of the regen till the supercap is full,but will still take time to deliver it to the battery bank.
Carbon fibre tow is cheap, I'm not sure of its electrical properties ( maybe similar to graphene), there are papers on the net about it, but i've never read them.
flathill said:
Hmm... seems to violate thermodynamic laws. But consider the theoretical case of a tiny one-way valve that allows gas molecules to pass in only one direction. A bunch of these in parallel would create a pressure on the downstream side and would be powered by the kinetic energy of the molecules. It could be possible.
There is so much that we don't know about physics....
MitchJi
10 MW
Hi Arlo,
Interesting, thanks for the post. Its not "70% of the current price", its up to a 70% reduction in price (30% of the current price
), made in the U.S. 
http://www.clbattery.com/
Arlo1 said:
Interesting, thanks for the post. Its not "70% of the current price", its up to a 70% reduction in price (30% of the current price
), made in the U.S. evwind said:
http://www.clbattery.com/
What?! 3x the cycles at as little as 30% of the cost sounds like the same price to me (3 x 30 = 90%). In 2014, sounds familiar.clbattery.com said:
But 70% reduction and 3 times the cycles, means I will save you 93.3% in the long run. So what do you mean it sounds familiar?REdiculous
10 kW
If you believe their claims and assume the calender-life is unaffected (or extended) then a battery that costs $200 today, will cost [/will be worth] about $46 when they start shipping*...
$200 * .7 = $140 / 3 = $46
* assuming they pass all the savings on to the consumer...haha..good luck. :wink:
$200 * .7 = $140 / 3 = $46
* assuming they pass all the savings on to the consumer...haha..good luck. :wink:
liveforphysics
100 TW
Anode is the cheapest part of a lithium cell.
Even if anodes became totally free, it would only drop cost by 10-15%.
Even if anodes became totally free, it would only drop cost by 10-15%.
Hillhater
100 TW
you can read that "Promo speak" any way you want !
If that life cycle is 4 times longer than the competitor,..it suggests this new cell costs you 70% less than 4 other cells !! ..
... and its cost is actually more than a similar cell ! :wink:
..notice its "life cycle cost" .. so all they are saying is it will cost 70% less than an equivalent cell over its life cycle.
If that life cycle is 4 times longer than the competitor,..it suggests this new cell costs you 70% less than 4 other cells !! ..
... and its cost is actually more than a similar cell ! :wink:
MitchJi
10 MW
Hi Arlo,
Waiting two years for a major breakthrough sounds familiar. Even though someday it will be true after hearing that familiar claim so many times its a little hard to get too excited about it.
MitchJi said:
I'd rather pay 30% of current prices for ~1,000 cycles rather than pay current prices for 3x the cycle life.Arlo1 said:
Waiting two years for a major breakthrough sounds familiar. Even though someday it will be true after hearing that familiar claim so many times its a little hard to get too excited about it.
Yeh I know.... Same reason I started building my own BLDC motor controller! Tired of waiting for some one to make a good one with in a reasonable price!MitchJi said:
So.... Once motor control is mastered then I guess I will have to learn how to DIY batteries!
oscarkipling
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Hey everyone, I've been lurking on this site for a long time, just taking in all the info that you guys have here. I saw this video and I immediately went to find the paper (i'll link if its not against the rules), With the addition of ionic liquids as an electrolyte these devices really appear to be competitive with conventional batteries as far as energy density and power density...anyway I thought about this place, I figured I'd probably find someone who was ambitious enough to build one of these and test them. Is anyone doing this here? I'm really giving it some consideration myself. So, is anyone doing this??
oscarkipling
1 µW
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Well, I got myself some GO and was able to replicate the graphene printing with a lightscribe drive. Its somewhat sensitive to the thickness of the GO film, but it does work. I was able to talk to one of the authors of the paper and she gave me some tips, also the supplemental notes and whatnot on the experiment here http://www.sciencemag.org/content/suppl/2012/03/14/335.6074.1326.DC1/El-Kady-SOM.pdf. Also I have some GO on sale in 50ml quantities if anyone else wants to try it out.
