New Nanomaterial With 3D Conductivity May Enhance Battery Storage

An international team of scientists has developed what may be the first one-step process for making seamless carbon-based nanomaterials that possess superior thermal, electrical and mechanical properties in three dimensions.

The research holds potential for increased energy storage in high efficiency batteries and supercapacitors, increasing the efficiency of energy conversion in solar cells for lightweight thermal coatings and more.

In early testing, a 3D fibre-like supercapacitor made with the uninterrupted fibres of carbon nanotubes and graphene matched or bettered - by a factor of four - the reported record-high capacities for this type of device.

Used as a counter electrode in a dye-sensitized solar cell, the material enabled the cell to convert power with up to 6.8 percent efficiency and more than doubled the performance of an identical cell that instead used an expensive platinum wire counter electrode.

"Two-step processes our lab and others developed earlier lack a seamless interface and, therefore, lack the conductance sought," said Liming Dai, Kent Hale Smith Professor of macromolecular science and engineering at Case Western Reserve University.

"In our one-step process, the interface is made with carbon-to-carbon bonding so it looks as if it's one single graphene sheet," Dai said. "That makes it an excellent thermal and electrical conductor in all planes."

The properties can be customised.

With the one-step process, the material can be made very long, or into a tube with a wider or narrower diameter.

The material can be used for charge storage in capacitors and batteries or the large surface could enable storage of hydrogen.

The scientists are continuing to explore the properties that can be derived from these single 3D graphene layer fibers and are developing a process for making multilayer fibers.

The study was published in the jourqnal Science Advances.