19 comments

[ 3.4 ms ] story [ 47.9 ms ] thread
novel ultra super ultra
superlative capacitors
super ultra high, not just super ultra
Interesting approach using a FET. I wonder how large this could be scaled?
If this is using the same fabrication technology as conventional integrated circuits, the price is proportional to die area so this is going to be very expensive for its size. I could see this powering a phone if the energy density is high enough, but there’s no way the economics would work out to power a car.
given that you're _trying_ to make huge gates with poor switching speed, my guess is you can use a pretty antiquated process
Just discharge your electrostatic charge before touching this capacitor. /s
Ah yes, the graphene. Material so abundant that Wikipedia's top right corner still contains only CGI render.
https://i.imgur.com/xdiQTLT.png

Like this? It's difficult to take a picture of an one atom thick material. You can also easily produce it at home if you'd like.

Or if you'd like to produce larger quantities, it seems like that's also doable at home with just a few hundred dollars of equipment: https://www.youtube.com/watch?v=3hHoL77QDkg

I was in the field briefly, but long enough to realise that graphene is a solution looking for a problem.

At least for a while, the approach was a blind search - with huge funding available to anyone claiming to be researching graphene applications, people were doing all kind of daft things with it. I don’t doubt that we’d be printing the stuff in metre-wide sheets by now if we hadn’t thrown so much money at trying to use it for everything from tuneable transistors (with the slight issue that mobility is inversely proportional to the bandgap) to throwing it into every conceivable medical application to see what sticks (with the slight caveat that every such paper I read at the time was actually talking about 50+ layer graphene, or as I’d call it “an actual pencil”).

I hope it’s in a better state now.

Based on the article scaling would require a lot of hand eye coordination!
The danger of improperly handling capacitors is well documented, but if they are deceptively small it might lead to carelessness. One of their little chips is probably innocuous enough. In series you had better be careful. Best case you melt your screwdriver. Worst case you melt your finger.

It sounds like a useful thing for regenerative braking, quick charging phones or perhaps as a replacement for a lead-acid car battery.

wow -3 and counting! Didn't anyone ever toss you a charged capacitor in class?
> For example, a capacitor operating at 5 volts will continue to operate at the same voltage even after a decade. But unlike batteries, they cannot discharge energy constantly—to power a mobile phone, for example.

What is this nonsense?

I had to reread it a few times but I think it's just poor phrasing, in the first sentence they are referring to the limited number of recharge cycles of most rechargeable batteries (which is generally much less applicable capacitors). And in the second sentence they are referring to the limited capacity of capacitors.
It think they are just rephrasing the famous "Beware of the charged capacitor" /s
They’re trying to explain that 1 farad at 1 volt is a watt second.

F = W * s / V²

AA batteries are around 4 watt hours so that’s somewhere around 6400 farads at 1.5V to do the same work. You need a 7f capacitor just to get within a factor of 1000 of the energy density of an alkaline cell. Ultra caps at present are in that neighborhood. So three orders of magnitude off.

Charcoal supercaps are limited to around 2.7 volts, and Maxwell Technologies made a huge deal out of getting their caps from 2.5V to 2.7V. That exponent makes that a 8% increase in voltage but a > 16% increase on power.

Nobody mentions the operating voltage of grapheme in this article.