Fabrication schematic of ordered mesoporous fewlayer carbon (OMFLC). Credit: Science (2015). DOI: 10.1126/science.aab3798
Like a battery, a capacitor is able to hold a charge, unlike a battery, however, it is able to be charged and discharged very quickly—the down side to capacitors is that they cannot hold nearly as much charge/ kg as batteries. The work by the team in China is a step towards increasing the amount of charge that can be held by supercapacitors (capacitors that have much higher capacitance than standard capacitors—they generally employ carbon-based electrodes)—in this case, they report a 3X increase using their new method—noting also that that their supercapacitor was capable of storing 41 watt-hours per kilogram and could deliver 26 kilowatts per kilogram to a device.
The new supercapacitor was made by first forming a template made of tubes of silica. The team then covered the inside of the tubes with carbon using chemical vapor deposition and then etched away the silica, leaving just the carbon tubes, each ~4 – 6 nm in length. Then, the carbon tubes were doped with nitrogen atoms. Electrodes were made from the resulting material by pressing it in powder form into a graphene foam.
MOA: Doping aided in chemical reactions within the supercapacitor without causing any changes to its electrical conductivity, which meant that it was still able to charge and discharge as quickly as conventional supercapcitors. The only difference was the dramatically increased storage capacity.
The team believes they are on the path to building a supercapacitor able to compete directly with batteries, perhaps even lithium-ion batteries. They note that would mean being able to charge a phone in mere seconds. But before that can happen, the team is looking to industrialize their current new supercapacitor, to allow for its use in actual devices.
http://phys.org/news/2015-12-carbon-doped-nitrogen-storage-capacity.htmljCp
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