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Battery innovation – supercapacitors

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Laptop slow to charge? I-phone flat by lunchtime?




SupercapacitorsBiggest hold-up in fast developing personal devices is the power sources. Lithium-ion technology is not that good.

Enter the supercapacitor

Supercapacitors don’t act like normal batteries. Theoretically – and it is only a theory – they could act as a power supply that not only charges your devices in minutes, but also gives those devices a charge that lasts for a longer period of time.

A normal battery is comprised of electrochemical cells. These cells consist of two electrodes separated by some distance, the space between them being filled with an electrolyte, which is a compound that converts to ions when dissolved in certain solvents, like battery acid. One of these electrodes allows electrons to flow out of it while the other receives them. The energy is stored in the compounds that make up the electrodes.

Supercapacitors are more environmentally friendly than their battery counterparts. Not only are the lifespans of supercapacitors longer than batteries (as they can be charged and recharged indefinitely), but they’re also much cleaner and safer. They don’t waste much energy, making them more efficient than batteries. And supercapacitors are not made using corrosive or toxic chemicals or metals.

Downside

Like a battery, Supercapacitors have a low energy density but currently (sic) can only hold 1/5th to 1/10th the energy of a standard battery. Because of the organic electrolyte used in supercapacitors, the fast energy discharge of a supercapacitor is much higher than that of a battery. Supercapacitors are low voltage devices: in order to achieve a practical working voltage, several need to be strung together. And at present, mass production of supercapacitors has not been something that is cost effective.

Because of these limitations, using supercapacitors in our home electronics and mobile devices is not yet feasible. However, thanks to strides in scientific research, we are very close to making breakthroughs that could change this.

Recently, a team of researchers uncovered a way to create graphene-based supercapacitors that charge and discharge three times faster than current lithium batteries. Graphene is the most conductive material known to man, but it can be tricky to produce and work with. The best part of this new discovery is that these graphene supercapacitors were created with a simple inexpensive DVD writer. The researchers learned that after putting a graphic oxide film on a blank DVD and then using the DVD’s laser to burn the CD, the graphic oxide is then turned into graphene. Once they had a few slices of graphene, an electrolyte was placed between the slices and a new kind of supercapacitor was born.

The researchers didn’t stop there, though. They began to play around with electrodes. As a result, the new supercapacitors have more charge capacity and rate capability than their stacked counterparts.

Micro-supercapacitors

A few years ago, a group of researchers at the Lawrence Berkeley National Laboratory USA began working on creating micro-supercapacitors. Using microfabrication methods similar to those which are already being used to create microchips for electronic devices, these researchers etched electrodes of monolithic carbon film into a substrate of conductive titanium carbide. The result was micro-supercapacitors that had an energy storage density at least twice as much as existing supercapacitors.

Thanks to the research at both UCLA and Berkeley, supercapacitors will be made smaller and cheaper, and may one day lead to more widespread use in smaller electronic devices. It’s only a matter of time before the world becomes a happier, more well-charged place.

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