Could hemp nanosheets topple graphene for making the ideal supercapacitor? | Hacker News Reader

Could hemp nanosheets topple graphene for making the ideal supercapacitor?

acs.org

37 pointsdutchbrit20 comments

Fully assembled, the devices performed far better than commercial supercapacitors in both energy density and the range of temperatures over which they can work. The hemp-based devices yielded energy densities as high as 12 Watt-hours per kilogram, two to three times higher than commercial counterparts. They also operate over an impressive temperature range, from freezing to more than 200 degrees Fahrenheit.

One wonders what the economic opportunity cost of the drug war has been.

Just gonna put this out there, but I swear this plant is like a miracle worker. Imagine what advances we would have made if this war on drugs hadn't kept hemp out of our reach for so long. Though someone please clarify if you can get hemp without marijuana (I am curious).

It's not as miraculous as some people in the US will go on and on about. I mean, it is definitely a useful plant but it's legal in many countries and hasn't become a major crop.

It's not technically legal in any country because of a UN treaty. I think part of the reason it hasn't 'taken off' in countries where laws aren't enforced/it's decriminalized/etc is because you can't transport it over the border, you can't sell to big clients in America (or anywhere else), the laws regarding distribution on such a large scale aren't clear enough even in places where it is "legal" so no one wants to put all their eggs in the marijuana basket at this point.

Hemp is marijuana as they are different names for the same plant, but industrial hemp has extremely low levels of psychoactive compounds.

Edit - apparently I may be wrong and marijuana plants are only the drug producing strains of the cannabis plant, but hemp and cannabis are more interchangeable as cannabis is the genus.

The reason for banning it is more about stuff like flying over a field with detection equipment looking for marijuana, it's not because hemp will get you high.

Looking at the history of it, the reason for banning it seems to be largely down to pressure from the cotton industry. So, the fact that some strains could get you high was the method used to outlaw it, not the reason why it was outlawed.

Ugh, I forgot I was posting in a pot thread.

maybe consider cutting back a little...

According to the BBC article at http://www.bbc.co.uk/news/science-environment-28770876, the original article author says "The hemp we use is perfectly legal to grow. It has no THC in it at all - so there's no overlap with any recreational activities."

You sir are absolutely correct. I first read about the uses of hemp a long while ago in Uncle Johns Bathroom reader (I shit you not). And that got me curious and looked into it more and its uses are quite vast and the cost to produce is relatively cheap! But again, existing industries have completely suffocated its growth through political influence and so virtually no one knows about its practicality. Real shame...

There's likely some bias here because stories about hemp tend to get better media coverage than other similar discoveries.

At any rate researchers can get it easily enough, so I highly doubt we're in some kind of lack-of-hemp-induced dark age.

Yes. http://en.wikipedia.org/wiki/Hemp

His team found that if they heated the fibers for 24 hours at a little over 350 degrees Fahrenheit, and then blasted the resulting material with more intense heat, it would exfoliate into carbon nanosheets.

Sounds like a similar process to the carbon-complex stuff that the ryden battery people are making from cotton. Nano materials might be easier to get in industrial quantities than I had previously thought, if you can strip them out of plants rather than having to build them up chemically. There presumably is an interesting crossover point here with genetic engineering, where you could alter a plant genome to encourage the formation of particular structures.

The energy density is still nowhere near Li-ion batteries. 12 Wh/kg vs. 150 Wh/kg.

Is it useful to compare capacitors to batteries in this fashion? It's not as though you could swap out one for the other, in pretty much any realistic application.

The hardware I work with uses a supercap to keep the real-time clock going during power failures. Previously, button cells were used for that.

whenever the headline is a question, its answer is probably "no"

Could this comment be right?

Betteridge's Law of Headlines

"Any headline which ends in a question mark can be answered by the word no."

https://en.wikipedia.org/wiki/Betteridge's_law_of_headlines

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