Cheap supercapacitor electrodes enable coin cells

July 19, 2017 // By Nick Flaherty
Cheap supercapacitor electrodes enable coin cells
Researchers at the University of Washington in the US have developed a fast, cheap method to make supercapacitor electrodes for electric cars and coin cells.

The method starts with carbon-rich materials that have been dried into a low-density matrix called an aerogel. The aerogel on its own can act as a crude electrode, but the team led by UW assistant professor of materials science and engineering Peter Pauzauskie more than doubled the capacitance

"In industrial applications, time is money," said Pauzauskie. "We can make the starting materials for these electrodes in hours, rather than weeks. And that can significantly drive down the synthesis cost for making high-performance supercapacitor electrodes."

A high surface area is a key requirement for storing chare as separate positive and negative charges directly on its surface. "One gram of aerogel contains about as much surface area as one football field," said Pauzauskie.

"Supercapacitors can act much faster than batteries because they are not limited by the speed of the reaction or the by-products that can form," said researcher Matthew Lim, a UW doctoral student in the Department of Materials Science & Engineering. "Supercapacitors can charge and discharge very quickly, which is why they're great at delivering these 'pulses' of power."

"They have great applications in settings where a battery on its own is too slow," said researcher Matthew Crane, a doctoral student in the UW Department of Chemical Engineering. "In moments where a battery is too slow to meet energy demands, a supercapacitor with a high surface area electrode could 'kick' in quickly and make up for the energy deficit."

He made aerogels from a gel-like polymer, a material with repeating structural units, created from formaldehyde and other carbon-based molecules. He and Lim loaded aerogels with thin sheets of either molybdenum disulfide or tungsten disulphide 10 to 100 thick. Both materials are widely used in industrial lubricants and so available at low cost.

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