A new easy, low-cost method for making microscale carbon-based supercapacitors capable of charging a cellphone in 30 seconds was revealed in a research paper published recently in Nature Communications.
Supercapacitors are similar to batteries, in that they hold large amounts of electric charge. However, they can charge and discharge a hundred to a thousand times faster than a battery.
Two scientists working at the California NanoSystems Institute at UCLA developed the process, which is much cheaper and easier than using typical solid-state micro-fabrication techniques that require a clean room and advanced equipment.
First, the researchers designed intricate circuit patterns with standard LightScribe software running on a PC.
Next, they covered an ordinary blank compact disc with a layer of plastic, and then painted it with a thin film of graphic oxide.
By inserting the coated CD into a DVD burner they directly “wrote” the circuit designs onto the graphic oxide with the burner’s laser light.
The exposed areas absorb the light and change the graphic oxide into graphene, a one-atom-thick sheet of carbon atoms that efficiently conducts electricity.
“With the precision of the laser, the drive renders the computer-designed pattern onto the graphite oxide film to produce the desired graphene circuits,” said Richard Kaner, the UCLA professor of materials science and engineering who led the research.
Done in half an hour
After 30 minutes, the process is complete and the flexible disc can be peeled off the CD.
Each disc holds more than 100 supercapacitors, which can be cut apart and then integrated into microelectronic chips, providing compact on-chip energy storage for cellphones, pacemakers, electronic papers and other electronic devices.
The new method could be used to mass produce microscale supercapacitors, and revolutionize the electronics industry.