Add ultracapacitors to the list of devices that could benefit from graphene

A scanning electron microscope image shows the ultracapacitor's composite film containing graphene flakes and single-walled carbon nanotubes.

A scanning electron microscope image shows the ultracapacitor's composite film containing graphene flakes and single-walled carbon nanotubes.

George Washington University researchers reported Tuesday that they have created an ultracapacitor that is both high performance and inexpensive to produce because it relies on a mix of two promising emerging materials: graphene and carbon nanotubes.

Like batteries, ultracapacitors are capable of storing a lot of energy in a small space. But they charge and discharge energy much faster than batteries. Once the technology is mature, ultracapacitors could be used in electric cars (Tesla CEO Elon Musk has said so himself) and even handheld devices.

Ultracapacitors are made of two plates separated by a thin layer of material. One plate is charged positively while the other is charged negatively, and the material in the middle is responsible for keeping them separated.

Graphene and carbon nanotubes, which are made of sheets of carbon atoms, are capable of transmitting electrons at super high speeds. As a result, lots of research teams have studied them for use as the divider in ultracapacitors. But after discovering an affordable way to produce large batches of mixed graphene and carbon nanotubes, the George Washington team decided to test them together. They made an ink out of the mix (pictured above) and rolled it onto paper.

The resulting divider performed three times better than carbon nanotubes on their own. Other materials have achieved the same performance, but the George Washington team’s mix is relatively cheaper.

 

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