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The Register reports
In a paper published at [Proceedings of the National Academy of Sciences] (abstract), the researchers claim capacitance of more than 1,100 Farads per cubic centimetre--or around 1,145 Farads per gram, which is about as much as they reckon you could get out of the manganese dioxide (MnO2) in the cap.
Using a combination of graphene and MnO2, the researchers say the energy density they can achieve can be as high as 42 Watt-hours per litre, which is getting close to that of a lead acid battery.
It's not much yet: the demonstrator pictured below from the UCLA California NanoSystems Institute is one-fifth the thickness of paper, however it can hold charge long enough to power the demo LED overnight.
That, the university claims, beats a thin-film lithium battery on a pound-for-pound (or rather gram-for-gram) basis.
Manganese dioxide is cheap and plentiful, and is good at storing charge--which is why it's popular in dry-cell batteries and alkaline batteries.
The combination of the MnO2 and laser-etched graphene--the secret sauce in all of this--can be produced without dry rooms or extreme temperatures.
(Score: 2) by richtopia on Tuesday April 07 2015, @06:40PM
Thank you for the clarification, I admit my original post was lacking.
I was recalling the major takeaway from a presentation from Dennis Corrigan, so my memory of the finer points may be flawed. From the abstract it looks like this paper covers the topic if anyone is interested (although it is paywalled; I imagine most universities could access ECS papers).