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[Image above] Credit: dave; Flickr CC BY-NC-ND 2.0

Microsupercapacitors may be our go-to energy storage device of the future. These guys can store a lot of energy in a small size, they charge and discharge quickly, and they have incredible lifespans—all obvious benefits for consumer electronic devices, and all perks that solve some of the challenges of batteries.

Many researchers think that supercapacitors will even eventually replace batteries altogether. But, so far, the technology hasn’t quite made it to the big leagues.

Back in 2010, an international team of researchers published a paper in Science describing a concept for monolithic carbide-derived carbon films that the scientists said would make finally microsupercapacitors possible.

The scientists’ idea to etch supercapacitor electrodes into titanium carbide films was really good—but that publication was a concept paper.

It was a well-thought and well-informed idea, but at the time the researchers still hadn’t confirmed that it was ultimately possible for commercial manufacturing.

In the time since that paper was published, the team has spent time in the lab testing, modeling, and perfecting the idea. And it’s paid off—the researchers have now bookended that original publication with a new Science paper that shows that the team’s idea to merge microchips and their power sources is not just feasible, but entirely doable. The team includes researchers from Drexel University (Philadelphia, Pa.), Paul Sabatier University (Toulouse, France), and the National Center for Scientific Research (CNRS, France).

Part of the scientists’ intervening research established the film’s compatibility, stability, and durability are sufficient to make the material of use in microsupercapacitors.

Confident that the material can live up to the concept, the team now shows that it can integrate microchips and power sources into one, opening the door to integrated power. And, because the films are also elastic, the finding represents a key to developing flexible electronics. 

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A layered membrane. Credit: Drexel University

“This has taken us quite some time, but we set a lofty goal of not just making an energy storage device as small as a microchip—but actually making an energy storage device that is part of the microchip and to do it in a way that is easily integrated into current silicon chip manufacturing processes,” senior author Patrice Simon—who led the research through a spin-off of Le Centre National de la Recherche Scientifique (CNRS) and France’s Ministry of Research—says in a Drexel Now news story. “With this achievement, the future is now wide open for chip and personal electronics manufacturers.”

The researchers sputtered a layer of titanium carbide, several micrometers thick, onto an oxide-coated silicon film. According to a summary from Science magazine, “After chlorination, most, but importantly not all, of the TiC was converted into a porous carbon film that could be turned into an electrochemical capacitor. The carbon films were highly flexible, and the residual TiC acted as a stress buffer with the underlying Si film. The films could be separated from the Si to form free-floating films, with the TiC providing a support layer.”

Beyond proving that the films are feasible, the team showed that its fabrication methods are consistent with current microchip fabrication procedures. The carbon films can be “seamlessly integrated” into silicon based-microchips, according to the release.

And, added bonus—the team showed that it could make the carbon films in various shapes, sizes, and configurations, opening up even more options for fabrication.

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A silicon chip containing microsupercapacitors. Credit: Drexel University

So what does that mean for consumer electronics?

“The place where most people will eventually notice the impact of this development is in the size of their personal electronic devices, their smart phones, fitbits89 and watches,” Yury Gogtsi, Distinguished University and Trustee Chair Professor in the Department of Materials Science Engineering at Drexel University (and also a Thomson Reuters influential scientific mind of 2015), says in the release. “Even more importantly, on-chip energy storage is needed to create the Internet of Things—the network of all kinds of physical objects ranging from vehicles and buildings to our clothes embedded with electronics, sensors, and network connectivity, which enables these objects to collect and exchange data. This work is an important step toward that future.”

The paper is “On-chip and freestanding elastic carbon films for micro-supercapacitors” (DOI: 10.1126/science.aad3345).