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How Supercapacitors Could Make Batteries a Thing of the Past

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Language: en

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Researchers recently and quite accidentally
discovered something that could change the
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whole electric car ballgame.
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If their predictions are accurate, we could
one day live in a world where cars can be
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fully charged in minutes instead of hours,
and their power storage units would last decades
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instead of years.
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What is this tantalizing breakthrough you
ask?
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A monumental leap forward in capacitor technology.
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Many of the current drawbacks of electric
cars stem from how batteries work.
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Batteries rely on chemical reactions, which
means for a lithium-ion battery to release
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energy you have to wait for the lithium to
shuffle through an electrolyte, and when you
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want to store energy you have to wait for
the lithium to shuffle back.
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Lithium-ion batteries also degrade, and replacing
one in an electric car would be enormously
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expensive.
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In contrast capacitors store static electricity,
like what builds up on a balloon as you rub
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it on your hair.
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Capacitors can be as simple as two metal plates
separated by air.
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When a current is applied to the plates, a
positive charge builds up on one plate and
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a negative charge builds up on the other.
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No electrolytes, no shuffling ions, just electrons
on a plate waiting to pounce like a caged
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lion.
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As a result capacitor can be fully charged
almost instantly, and since they can also
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deliver energy quickly, that means capacitors
can provide more power than batteries.
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They are much more durable than lithium-ion
batteries too, lasting through tons of charge
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and discharge cycles with little degradation.
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There is an achilles heel: they just can’t
hold very much energy.
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There are tricks to squeeze more charge onto
the plates, like increasing their surface
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area and reducing the distance between them
by swapping out the air with a thin insulator.
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Do that and you’ve created a supercapacitor,
but even then, the best supercapacitors today
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hold just 10 watt-hours per kilogram, about
5% of the energy of a lithium ion battery
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of the same weight.
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You would need a capacitor the size of a bus
to get any real use out of it.
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As it happens in 2010 Shanghai experimented
with electric buses powered by capacitors
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that charged up every couple of stops.
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That’s a pretty clever use for them, but
if you want a personal car smaller than a
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bus that can travel more than five miles without
stopping, capacitors are going to have to
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step up their game.
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Bizarrely the big breakthrough in supercapacitor
technology may come from… contact lenses?
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Soft contacts use a polymer mesh that can
swell up and store water.
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One of the original inventors has been tinkering
with the polymer ever since, and found that
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adding different elements imbues it with different
properties, like the ability to store electricity.
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Actually they were shocked at just how much
energy the polymer could store.
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A 2016 test of the little blue material found
it stored 100 times the energy the researchers
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expected.
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Since then they’ve been testing the material
to see if it works in real world conditions,
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and after 14 months of research have concluded
that the material could eventually store 180
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watt-hours per kilogram, putting it almost
on par with battery energy density, at least
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by weight.
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The supercapacitors could be quite a bit more
voluminous, perhaps 30% bigger than an equivalent
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battery.
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Still, they’d be faster to charge, cheaper
to make, and wouldn’t have the risk of catching
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fire since they’d be mostly water.
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They could also have applications outside
of cars, like storing energy for when it’s
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in high demand, or when renewable sources
aren’t generating electricity.
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For now regular old chemical batteries are
still the best fit for electric cars.
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But if this is the breakthrough the researchers
believe it is, batteries could be on their
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way out in the next decade.
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In a weird way, soft contact lenses may help
us see a brighter future.
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If you like what you see don’t forget to
subscribe.
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Just because capacitors are improving doesn’t
mean we’re not developing new and better
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batteries too.
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Like a squishy battery!
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You can learn more about that here!
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None other than Elon Musk himself has said
that supercapacitors are the future of electric
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cars.
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But he also thought a tiny submarine would help… so ya know,
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grain of salt and all that.
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Thanks for watching and I’ll see you next
time on Seeker.

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