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Flexible electronics could draw their energy from graphene supercapacitors

Imagine if your phone was always awake and processing data. How long would the battery last? Three hours? One hour? The next generation of electronics will require that kind of always-on energy consumption, but our current batteries are far from powerful enough to accommodate that.

Enter supercapacitors, which can store a much larger amount of energy in the same amount of space. Supercapacitors are generally not known for their stretchiness, but researchers based out of Duke, MIT and other laboratories have now created them out of crumpled sheets of graphene, a strong but stretcy material with interesting properties. They published their work in the journal Scientific Reports last week.

Graphene in various states of being crumpled. Photo by the researchers.
Graphene in various states of being crumpled. Photo by the researchers.

Graphene is made of a layer of carbon atoms just a single atom thick. To create a supercapacitor, the Duke team sandwiched a layer of stretchy gel between two sheets of graphene.

To make it stretchy, the researchers then crumpled the graphene sandwich up. If the supercapacitor needs to stretch or conform to a surface like a wrist, the graphene simply flattens a little. It can do this until it is up to eight times larger. It can be scrunched and flattened more than 1,000 times without seriously hurting its performance.

The team reports their graphene creation could also lend its unique abilities to a battery or a sensor. Other labs have already incorporated graphene into other parts of supercapacitors; at George Washington University, for example, a team mixed it with carbon nanotubes to create an ink that served the same purpose as the gel used in the Duke research.

Graphene’s super-thin nature makes it well-suited to wearable electronics. While right now the world might picture watches and glasses, wearable technology could someday be woven directly into our clothes or embedded in our bodies. When they are, atom-thick materials like graphene will be important resources.

3 Responses to “Flexible electronics could draw their energy from graphene supercapacitors”

  1. Fernando Gomez-Baquero

    Graphene papers can store more energy (more Li) per unit of weight than graphite. However, they store less energy per unit of volume, which is the relevant metric for applications such as electronic devices and electric vehicles. Graphene papers do have higher power densities than graphite, and this is mainly due to their high porosity/surface area.

  2. Ben Rupert

    Supercapacitors have a much lower energy density than lithium ion batteries. They store much less energy in a given amount of space. They charge and discharge much faster though, and so high a higher power density. They also can cycle many more times than lithium ion batteries.