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The Super Supercapacitor [video]

focusforwardfilms.com

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Re: The Super Supercapacitor [video]

#21

Post by CapitalistCartr »

hwillis wrote: post #11
mpweiher wrote: post #2

Very cool tech, and the manufacturing process looks doable as well. :-) Except for us poor mac-heads, how is iTunes going to make me some Graphene?? I was a bit disappointed that there weren't any numbers in the film, so I looked them up: http://www.extremetech.com/extreme/122763-graphene-supercapa... Energy density (storage capacity) does seem to be in range of Lithium Ion batteries, better than some, but still arou…

There also exist hybrid supercapacitors, which use a chemical reaction but act like capacitors. The best use of high-power capacitors is not as a replacement, its as a supplement. Current technology is not quite sufficient, but ideally it would mean that anything under a 20 minute drive could run off just the capacitor, which could(with sufficient infrastructure) charge in under a minute. It's not quite filling up on…

Chrysler made a turbine powered car in the Sixties. It would run on nearly anything. Unfortunately, Chrysler never pushed it to mass production, then the oil embargo put paid to that idea. But it was one of those beautiful futures of the Sixties.

http://en.wikipedia.org/wiki/Chrysler_Turbine_Car

Re: The Super Supercapacitor [video]

#22

Post by lutusp »

btilly wrote: post #15
lutusp wrote: post #10

Earlier quoted context omitted.

The warnings about nanomaterials are about their applications, not their mere existence. (The rational warnings, anyway.) Graphene is just a form of carbon, like graphite or diamond, neither of which is thought to be particularly hazardous. http://en.wikipedia.org/wiki/Graphene

Not necessarily true. As http://www.scientificamerican.com/article.cfm?id=carbon-nano... explains, the impact that asbestos has on our lungs is a mechanical process, and will be caused by any kind of hard object about the same size. A lot of nanomaterials have the potential for creating dust in this size, including ones made of pure carbon.

Yes, but this isn't a property unique to nanomaterials -- it's a generic risk common to all materials that can produce fine, abrasive dust. My point is this doesn't represent a nanomaterial risk, it's an ordinary risk in which the source happens to be a nanomaterial. Otherwise asbestos could be classed as a nanomaterial risk after the fact.

Is lunar surface material a nanomaterial? It's certainly nasty stuff and it gets everywhere. It's regarded as one of the primary risks in lunar colonization. Does that make it a nanomaterial?

Re: The Super Supercapacitor [video]

#23

Post by lutusp »

meaty wrote: post #19
lutusp wrote: post #12

Earlier quoted context omitted.

They won't know until they process this first step into a working device with conductors and all the essential elements of a real storage device. But in principle, a capacitor is a much better storage device than a battery -- no chemical conversions, no limit to charge-discharge cycles, many similar advantages.

They aren't magic. They have a relatively high self-discharge (or leakage depending on how you measure it) compared to say Li-ion/NiMh cells which means basically they piss capacity away slowly. Don't expect your wonderful supercap car to actually be charged if you leave it sitting there for a few hours.

> They have a relatively high self-discharge (or leakage depending on how you measure it) compared to say Li-ion/NiMh cells which means basically they piss capacity away slowly.

Your claim is premature -- they haven't chosen an insulator yet. The graphene sheets are the conducting surfaces, not the insulating layer. Your claims are about the properties of the insulating layer between graphene sheets, which hasn't been selected yet. It looks like this:

    Graphene (+) ---------------------------------
    Insulator ------------------------------------
    Graphene (-) ---------------------------------

Re: The Super Supercapacitor [video]

#24

Post by ableal »

CapitalistCartr wrote: post #21
hwillis wrote: post #11

Earlier quoted context omitted.

There also exist hybrid supercapacitors, which use a chemical reaction but act like capacitors. The best use of high-power capacitors is not as a replacement, its as a supplement. Current technology is not quite sufficient, but ideally it would mean that anything under a 20 minute drive could run off just the capacitor, which could(with sufficient infrastructure) charge in under a minute. It's not quite filling up on…

Chrysler made a turbine powered car in the Sixties. It would run on nearly anything. Unfortunately, Chrysler never pushed it to mass production, then the oil embargo put paid to that idea. But it was one of those beautiful futures of the Sixties. http://en.wikipedia.org/wiki/Chrysler_Turbine_Car

Fascinating. At the end there's a link to an earlier Fiat I did not know had existed: http://en.wikipedia.org/wiki/Fiat_Turbina (the photo reminded me of something familiar, took me a bit to figure out it was a guppy fish ;-)

Re: The Super Supercapacitor [video]

#25

Post by Dylan16807 »

tehwalrus wrote: post #18
DanWaterworth wrote: post #4

I haven't seen any mention of the efficiency. Does anyone have any numbers comparing a regular battery to a graphene supercapacitor?

hmm, I was going to jump in with "Capacitors are never more than 50% efficient, because physics" but it seems only if you charge from nothing at a constant current: http://www.scribd.com/doc/79500452/ANALOG-SEEKrets-DC-to-Day... (filed under "today I learned")

You didn't know you could connect a capacitor to an inductor and let it bounce away until resistance slowly drained the power?

And it's not constant current that would hurt you, it's constant voltage. Because the extra voltage bleeds away into the resistance of your components. If you had ideal components without resistance or inductance it would be impossible to actually apply a pure voltage source to a capacitor.

Re: The Super Supercapacitor [video]

#26

Post by brokentone »

I got my dad an ultracapacitor flashlight (http://www.ohgizmo.com/2008/11/10/ultracapacitor-flashlight-...) a few years back and he loved it till it got stolen. Really quick recharge time, decent "battery" life.

Interestingly this flashlight was discontinued, and I don't see any new ones on 5.11 tactical's website. I wonder why?

I'm really interested in any increases in these types of technology, love to see what comes of this.

Re: The Super Supercapacitor [video]

#27

Post by ars »

Egregore wrote: post #8

In the video they show that graphene can be thrown away in compost bin safely, how is it related to all the warnings we have about nanomaterials being dangerous?

They are dangerous to breathe. They are safe to touch or eat.

Re: The Super Supercapacitor [video]

#28

Post by achy »

Having a better conducting, higher surface area electrode is a huge step. BUT it doesn't really change the fact that a carbon based supercapacitor requires an electrolyte to form the double layer, and all existing electrolytes have a breakdown voltage below 5V. What we need is a better electrolyte. In calculating energy storage in a capacitor, the energy increases exponentially with voltage, while linearly with capacitance.

Re: The Super Supercapacitor [video]

#29

Post by meaty »

lutusp wrote: post #23
meaty wrote: post #19

Earlier quoted context omitted.

They aren't magic. They have a relatively high self-discharge (or leakage depending on how you measure it) compared to say Li-ion/NiMh cells which means basically they piss capacity away slowly. Don't expect your wonderful supercap car to actually be charged if you leave it sitting there for a few hours.

> They have a relatively high self-discharge (or leakage depending on how you measure it) compared to say Li-ion/NiMh cells which means basically they piss capacity away slowly. Your claim is premature -- they haven't chosen an insulator yet. The graphene sheets are the conducting surfaces, not the insulating layer. Your claims are about the properties of the insulating layer between graphene sheets, which hasn't bee…

Charge leaks through the conductors as well into the connecting circuits, through the packaging and the adhesives. No insulator doesn't leak.

Re: The Super Supercapacitor [video]

#30

Post by deanotron »

Egregore wrote: post #8

In the video they show that graphene can be thrown away in compost bin safely, how is it related to all the warnings we have about nanomaterials being dangerous?

The warnings comparing carbon-nanotubes to asbestos are simply because of the shape of the structure - they are both microscopic needles and our white blood cells don't do a good job of breaking them down.

Not all nanomaterials are dangerous (just as varying sizes of dust are not), but many new materials may adopt unnatural properties that our body doesn't know how to deal with. So there is still handwavyness to it all.

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