This is a diagram of the dielectric capacitor research developed by a University of Delaware-led research team. Credit: Kathy F. Atkinson/University of Delaware
Nanotechnology offers new approach to increasing storage ability of dielectric capacitors. In the movie ‘Back to the Future,’ Doc Brown and Marty McFly landed in the future in their DeLorean, with time travel made possible by a ‘flux capacitor.’ Today, capacitors are key components of portable electronics to electric cars, providing fast delivery of energy but poor storage capacity. Researchers now report a new approach to increasing storage ability.
In contrast to batteries, which offer high storage capacity but slow delivery of energy, capacitors provide fast delivery but poor storage capacity. A great deal of effort has been devoted to improving this feature – known as energy density – of dielectric capacitors, which comprise an insulating material sandwiched between 2 conducting metal plates.
“With our approach, we achieved an energy density of about 2 watts/kg, which is significantly higher than that of other dielectric capacitor structures reported in the literature,” says Bingqing Wei, professor of mechanical engineering at UD. “To our knowledge, this is the first time that 3D nanoscale interdigital electrodes have been realized in practice,” he adds. “With their high surface area relative to their size, carbon nanotubes embedded in uniquely designed and structured 3D architectures have enabled us to address the low ability of dielectric capacitors to store energy.”
One of the keys to the success of the new capacitor is an interdigitated design – similar to interwoven fingers between two hands with “gloves” – that dramatically decreases the distance between opposing electrodes and therefore increases the ability of the capacitor to store an electrical charge.
Another significant feature of the capacitors is that the unique new 3D nanoscale electrode also offers high voltage breakdown, which means that the integrated dielectric material (alumina, Al2O3) does not easily fail in its intended function as an insulator.
“In contrast to previous versions, we expect our newly structured dielectric capacitors to be more suitable for field applications that require high energy density storage, such as accessory power supply and hybrid power systems,” Wei says. http://www.udel.edu/udaily/2016/oct/dielectric-capacitor-102315.html
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