Supercapacitors present an amazing opportunity to move away from batteries
and into a world where almost instant charging is the norm.
But their drawbacks mean we can’t use them widely...yet.
Experiments with a new class of materials that are related to soap and laxatives (yes, laxatives)
could bring us one step closer to a world with no more pesky chemical batteries.
So here’s the deal with batteries.
Many batteries we’re familiar with are chemical,
which means they use some kind of charged chemical, like lithium, to store energy.
Lithium ion batteries are in everything from your phone and your laptop to electric cars,
but they’ve got some downsides. You’ve gotta wait ages for them to charge.
They start degrading basically as soon as they leave the factory,
and they’re very expensive to replace because they’re super resource intensive—
which also means they’re really not great for the environment.
They also contain highly flammable electrolytes, meaning they pose a safety risk.
I’m sure we all remember the exploding hoverboards of several years back.
These are issues for consumer electronics, yes,
but also means there are some serious restrictions for using these kinds of batteries in say, our energy grid.
Enter an excellent alternative: supercapacitors.
And just to be clear—supercapacitors are the same concept as capacitors,
which we use in many products today, just with some materials added to help them hold more charge.
Instead of chemical energy like batteries,
capacitors store energy in the form of static electricity:
you know, the same kind that shocks you
when you touch someone after shuffling across the carpet in your socks.
Supercapacitors consist of two electrode plates soaked in a liquid electrolyte, separated by an insulator.
Apply a voltage, and voilá, opposite electric charges build up on the plates, creating an electric double-layer,
allowing them to store more energy than regular capacitors.
So a supercapacitor’s energy is stored in its electric field, whereas a battery’s is stored in its chemical makeup.
There’s a key thing to understand here when we talk about the difference between batteries
and supercapacitors: energy density vs. power density.
Energy density is the amount of energy that can be stored in a given mass,
whereas power density is how fast that energy can be discharged.
So supercapacitors have a much higher power density than batteries,
meaning they can pack a real punch of energy real fast when you need them to.
But they also have a much lower energy density than chemical batteries,
meaning they can store less energy overall.
But they also recharge super fast:
supercapacitors can be charged in seconds or minutes,
rather than the hours it can take to charge a battery as big as the one in your electric car.
These trade-offs exist because supercapacitors can only store as much energy as they can hold
at the interface of their electrodes and their electrolyte.
Picture it like this: if a battery is a sponge, full of energy,
a supercapacitor is only able to use the surface of its sponge.
Sure, you can get the water out faster...but it holds less water.
This has been the main thing keeping supercapacitors from becoming our energy storage of choice—
they just don’t hold enough energy to reasonably power the stuff we use every day.
But new materials could change that.
The researchers are calling them SAILs, short for surface-active ionic liquids,
and you may be surprised to hear that their molecular components are also found in something
we use everyday...soap.
Or more accurately, detergents.
Like soap and even laxatives,
this new class of electrolytes contain molecules that are dipolar,
meaning that their heads and tails have opposite charges.
This means that unlike conventional electrolyte materials,
these ionic liquids can self assemble into a bi-layer structure, a little bit like a sandwich.
And their charge and the way they assemble is the crucial part.
The dense layers of charged ions at the surface of the electrode allow them to store much more energy...
maybe as much as a lithium ion battery.
But there is a lot more work to be done.
These supercapacitors still require certain temperatures and voltages
to achieve their impressive leap in energy storage.
The researchers also emphasize the need to keep developing this technology,
and entire systems that incorporate SAILs to make supercapacitors practical on a larger scale.
But this work is hugely exciting and could take us one step closer to a new era
of almost instantly rechargeable,
cheaper, and more environmentally friendly energy storage...
hopefully changing the way we charge forever.
For more info on supercapacitor technology, check out this video here,
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As always, thanks so much for watching—and we’ll see you next time.