Scaling Up Production of Graphene Micro-Supercapacitors
- Tuesday, 12 March 2013
The demand for ever-smaller electronic devices has led to the miniaturization of a variety of technologies, but energy-storage units, such as batteries and capacitors, have lagged behind. Now, researchers at UCLA say that they have developed an innovative technique using a DVD burner to fabricate micro-scale graphene-based supercapacitors, which can charge and discharge a hundred to a thousand times faster than standard batteries.
These micro-supercapacitors, made from a one-atom–thick layer of graphitic carbon, can be easily manufactured and readily integrated into small devices such as next-generation pacemakers, they say.
The new cost-effective fabrication method, described in the journal, Nature Communications, holds promise for the mass production of these supercapacitors, which have the potential to transform electronics and other fields.
Traditional methods of fabricating micro-supercapacitors involve labor-intensive lithographic techniques that have proven difficult for building cost-effective devices, limiting commercial application, they say. Instead, the UCLA team said that they have produced more than 100 micro-supercapacitors on a single disc in less than 30 minutes, using inexpensive materials, and took advantage of a new structural design during the fabrication. For any supercapacitor to be effective, two separated electrodes have to be positioned so that the available surface area between them is maximized, allowing the supercapacitor to store a greater charge.
Previous designs stacked the layers of grapheme, but in their new design, the researchers placed the electrodes side by side using an interdigitated pattern, like interwoven fingers, which helped to maximize the accessible surface area available for each of the two electrodes while reducing the path over which ions in the electrolyte would need to diffuse.
As a result, the new supercapacitors have more charge capacity and rate capability than their stacked counterparts, and by placing more electrodes per unit area, they boosted the micro-supercapacitor’s ability to store even more charge.