If these UCLA researchers are right – and we might find out pretty soon – energy storage could be in for a big change.
Richard Kaner and his graduate student Maher El-Kady have been trumpeting graphene micro-supercapacitors that would combine the very fast charge and discharging capabilities of supercapacitors – hundreds of times faster than batteries – with the high energy density of batteries.
Now the researchers say they have demonstrated a scalable fabrication process that could make their supercapacitors cheap to produce while expanding the possibilities for their use.
“We are now looking for industry partners to help us mass-produce our graphene micro-supercapacitors,” Kaner said in a statement.
The duo actually came up with the essence of their breakthrough nearly a year ago, with this brilliant technique, according to UCLA:
They glued a layer of plastic onto the surface of a DVD and then coated the plastic with a layer of graphite oxide. Then, they simply inserted the coated disc into a commercially available LightScribe optical drive — traditionally used to label DVDs — and took advantage of the drive’s own laser to create the interdigitated pattern. The laser scribing is so precise that none of the “interwoven fingers” touch each other, which would short-circuit the supercapacitor.
To take the supercapacitor to the next level, UCLA said, the researchers tinkered with the electrodes, placing them “side by side using an interdigitated pattern, akin to interwoven fingers,” UCLA said. “This helped to maximize the accessible surface area available for each of the two electrodes while also 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.”
The researchers add that “these micro-supercapacitors show excellent cycling stability, an important advantage over micro-batteries, which have shorter lifespans and which could pose a major problem when embedded in permanent structures – such as biomedical implants, active radio-frequency identification tags and embedded micro-sensors – for which no maintenance or replacement is possible.”
They also imagine the possibility of fabricating the micro-supercapacitors behind solar cells “in both portable devices and rooftop installations to store power generated during the day for use after sundown, helping to provide electricity around the clock when connection to the grid is not possible.”
The UCLA research was published in the journal Nature Communications.
Here’s a video, featuring Kaner and El-Kady, that gives some good background on graphene and supercapacitors and what this breakthrough could mean: