
Aerogel from fruit biowaste produces ultracapacitors - dalf
https://www.sciencedirect.com/science/article/pii/S2352152X19309077
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westurner
> _" Aerogel from fruit biowaste produces ultracapacitors with high energy
> density and stability" (2020)
> [https://www.sciencedirect.com/science/article/pii/S2352152X1...](https://www.sciencedirect.com/science/article/pii/S2352152X19309077)
> _

Years ago, I remember reading about supercapacitor electrodes made from what
would be waste hemp bast fiber. They used graphene as a control. And IIRC, the
natural branching structure in hemp (the strongest natural fiber) was
considered ideal for an electrode.

"Hemp Carbon Makes Supercapacitors Superfast" [https://www.asme.org/topics-
resources/content/hemp-carbon-ma...](https://www.asme.org/topics-
resources/content/hemp-carbon-makes-supercapacitors-superfast)

How do the costs and performance compare? Graphene, hemp, durian, jackfruit

While graphene production costs have fallen due to lots of recent research,
IIUC all graphene production is hazardous due to graphene's ability to cross
the lungs and the blood-brain barrier?

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m463
All my life, I've heard people go on and on about the magical properties of
hemp.

It's hilarious.

They have these material science level arguments about hemp, yet the same
people would be hard pressed to find an alternative use for cotton aside from
clothes, or wood pulp aside from ikea furniture.

It's a desert topping, it's a driveway sealant. And the government won't let
us have it!

~~~
westurner
Hemp textiles are rough, but antimicrobial/antibacterial: hemp textiles resist
growth of pneumonia and staph.

AFAIU, when they blend hemp with e.g. rayon it's good enough for underwear,
sheets, scrubs.

The government is getting the heck out of the way of hemp, a great rotation
crop that can be used for soul remediation.

~~~
dflock
> soul remediation.

That's the best pun - or typo - that I've seen in a while.

~~~
okonomiyaki3000
Maybe a freudian slip

~~~
westurner
#AccidentalArt.

(Freudian psychoanalytic projections are not supported by neuroimaging)

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dalf
An article that sums up the idea:
[https://www.popularmechanics.com/technology/design/a31114696...](https://www.popularmechanics.com/technology/design/a31114696/durian-
fruit-stinky-electric-chargers/)

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aero-
How does the storage capacity of these biowaste supercapicitors compare to
that of a synthesized or inorganic material?

Is the Jackfruit and Durian selected because its spongy properties after being
autoclaved?

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viggity
Title sounds like it was created by an HN article generator.

~~~
csours
HN Mad Titles, now you can play at home!

___tech_thing___ FROM ___mundane_trash___ PRODUCES ___space_magic_thing___!

~~~
markrages
[https://twitter.com/HNTitles](https://twitter.com/HNTitles)

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mrfusion
General capacitor question

If you take a charged parallel plate capacitor and pull the plates farther
apart does the energy in the system go up or down?

The equations seem to be geared to how distance affects how much you can
charge a capacitor. But if it’s already holding a given charge, I don’t think
the basic equation applies.

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marcosdumay
If you hold the charge constant and capacitance goes down, voltage will go up
(U = QC). The energy is (E = U^2C/2), so yes the energy will increase.

That extra energy is coming from your mechanic effort of separating two plates
that attract each other.

~~~
mrfusion
Ok wow that makes sense. So I’d actually have a hard time pulling them apart?

What’s the limit? What happens 1 meter apart? 20 meters?

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hwc
As long the capacitors have a width much larger than the distance between
them, the energy stored is (if I recall correctly) linear. this is because the
electric field is a constant vector field between the plates.

Once that is not true, you will transition to just separating two charged
objects. Use Coulombs law to figure out the force. (Work energy is integral of
force over distance).

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nirav72
I'd like to see aerogel batteries one day.

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sitzkrieg
wonder if any smell remains from the durian

~~~
mizunooto
Hence “Duracell“

