An MIT research group has crumpled a sheet of graphene to produce a super capacitor. The discovery could be used as a power source in flexible and wearable electronics in the future
Flexible electronics have been on the horizon for a long time. Unfortunately, there’s more to making, e.g. electronic paper, than producing a bendable screen. All components have to be flexible, and that includes the power source. MIT’s Xuanhe Zhao, an assistant professor of mechanical engineering and civil and environmental engineering, may have found such a power source: crumpled graphene.
Graphene is a material composed of a single layer of carbon arranged in a hexagonal pattern. It is incredibly strong and has been making news all around the tech and physics world since it was first produced in 2004 (an achievement which won the Nobel Prize). By crumpling this material, like you would a piece of paper, the graphene can be used as a highly flexible super-capacitor, capable of storing all the energy your electronics will need. “Many people are exploring graphene paper: It’s a good candidate for making supercapacitors, because of its large surface area per mass,” Zhao says.
Unlike a conventional battery, which produces electricity chemically, a capacitor stores it’s energy electrostatically, meaning it can deliver that electricity faster. In order to turn graphene into a capacitor, one simply needs two sheets of material with an isolator (in this case hydrogel) in between.
Basic schematic of a super capacitor
Zhao’s research team was able to fold the material up to 1000 times, producing a very stretchable and flexible capacitor. It was placed in a machine which compressed it in one direction, producing folds along the material. After this, it was compressed along another axis, until the graphene sheet was a mess of folds and pockets. The reason the sheet didn’t break during this process is because of graphene’s incredible robustness.
At this point, the research team was focusing on creating a capacitor with the graphene, but they have stated that the material could easily be adapted to provide flexible electrodes for a battery or to make sensors for medical applications.
Dan Li, a professor of materials engineering at Monash University in Australia who was not involved in the research, commented on it’s importance: ” While other groups have made flexible supercapacitors. Making supercapacitors stretchable has been a great challenge. This paper provides a very smart way to tackle this challenge, which I believe will bring wearable energy storage devices closer.”