Scientists ‘fry’ graphene oxide for battery material

Scientists are trying to develop material for batteries by ‘frying’ graphene oxide as a spray. In this way it is relatively easy to make ‘3d graphene’ spheres, which can be used as material for electrodes.

The scientists use sound waves to convert a suspension of graphene oxide flakes into microdroplets. They then spray these drops into an organic solution with a temperature of 160°C, a method they compare with deep-frying.

When frying, the water evaporates and the flakes clump together. “We believe the rapid evaporation causes the graphene layers to have a radially outward arrangement,” said Sang-Hoon Park of Korea’s Yonsei University in Seoul. The balls look like microscopic pompoms. The advantage of this design is that there is a large graphene surface, whereby nanochannels can provide a greater charge transfer.

The researchers used the graphene spheres to make electrodes measuring 1 by 1 cm. Its capacitance was comparable to that of 3d graphene electrodes obtained by other means. The advantage of the researchers’ method, however, is that it is simple and can be easily scaled up for industrial applications, Chemical & Engineering News quotes a Korean scientist as saying.

It has been known for some time that graphene can be used for electrodes thanks to its electrical properties. Graphene consists of a single layer of carbon atoms in an arrangement that resembles chicken wire. 3D graphene structures would have better properties for use as electrode material due to their larger surface area. The larger surface area means more space for electrons at the interface, a better exchange of electrons and a larger battery capacity.