Graphene is a material that has been around since the sixties. It is a pure carbon molecule where the atoms are arranged in a pattern looking like a miniature chicken wire. It is an allotrope of carbon with the atoms arranged on a single sheet.
The material has many interesting properties. One of them is the ability to form a capacitor that can hold a relatively large amount of charges. This supercapacitor can be used as a battery. One of the main road blocks have been the issue of producing graphene on an industrial scale so it is affordable.
Recently a lot of developments occurred in this area. Andre Geim and Konstantin Novoselov had the Nobel Prize awarded in 2010. In 2011, Jacek Baranowski in Warsaw was able to produce graphene on an industrial scale. In 2013 Jari Kinaret’s team at Chalmers University, was awarded a one-billion-euro grant from the European Union for Graphene research.
There is also a very recent development in the US. El-Kady and Kaner at UCLA are in the process of publishing their new results in the upcoming issue of Nature Communications. They found a method based on El-Kady’s previous results that yielded a potential manufacturing process. They created a video with Brian Golden Davis, showing a more efficient and way of manufacturing, raising the possibility of mass production. “More than 100 micro-supercapacitors can be produced on a single disc in 30 min or less.”
El-Kady and Kaner developed a method where they embed small electrodes into the graphene units. Then it is placed on a flexible substrate allowing the supercapacitor itself to be flexible. According to the researchers the energy density of this unit is comparable to a thin-film lithium-ion batteries.
The advantage of supercapacitors is that they can be charged faster than batteries. The team envisions future products where a smart phone would be charged in seconds enough to operate for a day. Although there might be other issues like heat dissipation or the capacity of the charging source.
“The new micro-supercapacitors are also highly bendable and can be twisted, making them potentially useful as energy-storage devices in flexible electronics like roll-up displays and TVs, e-paper, and even wearable electronics. The researchers showed the utility of their new laser-scribed graphene micro-supercapacitor in an all-solid form, which would enable any new device incorporating them to be more easily shaped and flexible. The micro-supercapacitors can also be fabricated directly on a chip using the same technique, making them highly useful for integration into micro-electromechanical systems (MEMS) or complementary metal-oxide-semiconductors (CMOS). As they can be directly integrated on-chip, these micro-supercapacitors may help to better extract energy from solar, mechanical and thermal sources and thus make more efficient self-powered systems. They could also be fabricated on the backside of 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.”
Kaner says that his lab is now looking for partners in industry that can help make these graphene supercapacitors on an industrial scale.