Posted on 12/03/2015 12:56:53 PM PST by Red Badger
Rice University scientists are making small, flexible microsupercapacitors in a room-temperature process they claim shows promise for manufacturing in bulk. The technique is based on their method to burn patterns of spongy graphene into plastic sheets with a commercial laser. Credit: Tour Group/Rice University ======================================================================================================================================
Rice University researchers who pioneered the development of laser-induced graphene have configured their discovery into flexible, solid-state microsupercapacitors that rival the best available for energy storage and delivery.
The devices developed in the lab of Rice chemist James Tour are geared toward electronics and apparel. They are the subject of a new paper in the journal Advanced Materials.
Microsupercapacitors are not batteries, but inch closer to them as the technology improves. Traditional capacitors store energy and release it quickly (as in a camera flash), unlike common lithium-ion batteries that take a long time to charge and release their energy as needed.
Rice's microsupercapacitors charge 50 times faster than batteries, discharge more slowly than traditional capacitors and match commercial supercapacitors for both the amount of energy stored and power delivered.
The devices are manufactured by burning electrode patterns with a commercial laser into plastic sheets in room-temperature air, eliminating the complex fabrication conditions that have limited the widespread application of microsupercapacitors. The researchers see a path toward cost-effective, roll-to-roll manufacturing.
"It's a pain in the neck to build microsupercapacitors now," Tour said. "They require a lot of lithographic steps. But these we can make in minutes: We burn the patterns, add electrolyte and cover them."
Their capacitance of 934 microfarads per square centimeter and energy density of 3.2 milliwatts per cubic centimeter rival commercial lithium thin-film batteries, with a power density two orders of magnitude higher than batteries, the researchers claimed. The devices displayed long life and mechanical stability when repeatedly bent 10,000 times.
Rice University scientists are making small, flexible microsupercapacitors in a room-temperature process they claim shows promise for manufacturing in bulk. The technique is based on their method to burn patterns of spongy graphene into plastic sheets with a commercial laser. Credit: Tour Group/Rice University =====================================================================================================================================
Their energy density is due to the nature of laser-induced graphene (LIG). Tour and his group discovered last year that heating a commercial polyimide plastic sheet with a laser burned everything but the carbon from the top layer, leaving a form of graphene. But rather than a flat sheet of hexagonal rings of atoms, the laser left a spongy array of graphene flakes attached to the polyimide, with high surface area.
The researchers treated their LIG patterns—interdigitated like folded hands—with manganese dioxide, ferric oxyhydroxide or polyaniline through electrodeposition and turned the resulting composites into positive and negative electrodes. The composites could then be formed into solid-state microsupercapacitors with no need for current collectors, binders or separators.
Tour is convinced the day is coming when supercapacitors replace batteries entirely, as energy storage systems will charge in minutes rather than hours. "We're not quite there yet, but we're getting closer all the time," he said. "In the interim, they're able to supplement batteries with high power. What we have now is as good as some commercial supercapacitors. And they're just plastic."
Explore further: Defects are perfect in laser-induced graphene
More information: Lei Li et al. High-Performance Pseudocapacitive Microsupercapacitors from Laser-Induced Graphene, Advanced Materials (2015). DOI: 10.1002/adma.201503333
Journal reference: Advanced Materials
Tech Ping!..............
FULL TITLE:
Scientists see the light on microsupercapacitors: Laser-induced graphene makes simple, powerful energy storage possible
Super capacitors have been possible for a while.
The problem they and this new iteration have is explosive discharge.
If a gas tank on a vehicle is damaged you get a leak, maybe a fire. It would have to leak for a bit and build up a vapor that was later ignited to get an explosion.
Super capacitors make a big boom every time one with a big charge is damaged.
These are MICRO-SuperCapacitors, meant for low voltage requirements...Even a common alkaline or carbon cell will get hot enough to burn if a short circuit is applied..................
As someone who knows a bit about batteries I’ve been saying for years that chemical batteries are a dead end. Capacitave storage is the ticket. Superfast recharge times. And it doesn’t take several times the amount of charge out to recharge them. Capacitive recharge is closer to 1:1 as opposed to 3-4:1 like a chemical battery. They will eventually replace batteries in most applications IMHO.
The thing about conventional batteries is their chemicals wear out or are lost thru discharge/discharge cycles. Their ‘storage’ is dependent upon the presence of these chemicals being possible to rejuvenate.
But with super capacitors, they actually store electrons within their atomic structure, which does not change appreciably over time......................
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Awesome, if they can work out large-scale manufacturing.
The next huge problem will be current: you can charge a capacitor really fast, but having the power source capable of transferring that much electricity that fast is a problem. Not so big for little things like phones, but cars are a problem - takes me 20 hours to charge my EV on house current (1400 watts, 110v), or 4 hours on 6.6kWh & 220v, or (if so equipped ) about 30 minutes at 440v - but the latter takes a $30,000 charger and thick wiring. Replace that big battery with a giant capacitor, and the limiting factor will be wiring infrastructure, making charging as slow as is now.
BTW: I was at Kodak at the tipping point for digital. They forgot their customers were the button-pushers taking pictures, not the retailers moving pallet-loads of product. Once the public discovered endless “film” for one moderate purchase, the conversion took months - not 5 years like executives expected.
I believe this type of device will supplant the conventional battery fairly quickly, in phones, toys, portable radio/stereos, and especially digital cameras. The Big Battery companies better get on board quickly, pun intended............
Thanks Red Badger.
There is a reason UFOs are attracted to the top of thunder storms ...
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