Innovation That Matters

This image, taken with high resolution microscopy, shows how, in the upper part of the biphenylene network, carbon atoms link together as squares, hexagons and octagons. The lower part is an image of this | Photo source University Marburg & Aalto University

A novel form of carbon for use in lithium batteries


Researchers have created a new form of carbon which is similar to graphene, but has unique properties

Spotted: Carbon, the building block of life, exists in various forms. These include diamond and graphite, as well as graphene, which is just one atom thick and has a number of unusual properties. Now, researchers at Finland’s Aalto University and the University of Marburg in Germany, have developed an entirely new form of carbon. Dubbed biphenylene, the new material is similar to graphene but has unique electrical properties that could have important applications.

In graphene, each carbon atom is linked to three neighbours, forming hexagons arranged in a honeycomb network. The new material is also one atom thick, like graphene, but is made up of squares, hexagons, and octagons forming an ordered lattice. The researchers used high-resolution scanning probe microscopy to confirm the structure of biphenylene.

The new material is made by assembling carbon-containing molecules on a gold surface. The molecules first form chains, and a second reaction connects these chains together to form the squares and octagons. The chains are also chiral, which means that they exist in two mirroring types. Only chains of the same type aggregate and connect on the gold surface. This is what leads to the assemblage of biphenylene instead of graphene. 

Graphene has incredible strength, flexibility and lightness, and acts as an excellent conductor of heat and electricity. Biphenylene, in contrast, can also behave like a metal. The researchers propose that strips of biphenylene just 21 atoms wide could work as conducting wires in carbon-based electronic devices. “The new idea is to use molecular precursors that are tweaked to yield biphenylene instead of graphene”, explains Linghao Yan, who carried out the high-resolution microscopy experiments at Aalto University.

We have already seen a range of innovative uses for graphene. These have included a graphene-based superbattery that could charge quickly and release large bursts of energy, and an ultra-white paint that passively cools buildings to save energy. This new form of carbon could have further uses.

Written By: Lisa Magloff

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