Researchers at the Rensselaer Polytechnic Institute (RPI), New York, USA, have come up with a way to transform high-quality 2D sheets of graphene into macroscopic 3D structures that could be used for applications such as thermal management for high-power electronics, structural composites, flexible and stretchable electrodes for energy storage, sensors, and membranes.
Once of the core tasks in bringing graphene to the 3D world is maintaining its attractive thermal and electrical properties, seen in 2D, and achieving the mechanical strength observed in its three-dimensional form – both tasks the RPI team managed to accomplish.
“The discovery of the highly thermally-conductive and mechanically-strong fibres using different-size graphene sheets is unprecedented for conventional fibre technology,” said one of the researchers and project lead author Jie Lian.
The fibre was made with a scalable wet spinning process, according to Lian, and he believes the strategy of using different-sized sheet structures can be applied to construct macroscopic structures (papers, fibres, tubes and fabrics) for other materials with 2D sheet structures.
Macroscopic graphene oxide, assembled from a dispersion in aqueous media by a simple wet spinning process, has been achieved in the past, but retained neither the material’s mechanical strength, nor its thermal properties.
The new method, characterised by improved graphene sheet alignment, compactness and removal of defects and functional groups in order to enhance the physical properties, was designed in response to other techniques failing to retain graphene’s thermal qualities due to sub-optimal microstructures and defects in the fibres themselves.
Encouraged by the results and unafraid of the work ahead, the researchers are already considering to tackle goals more lofty than “mere” better understanding of the fibres’ interior structure.
“We are also interested in exploring the large-scale manufacturing of graphene fibres by wet spinning process or combining with additive manufacturing for large-scale components,” said Lian. “This should lead us to using graphene fibres in functional textiles for thermal energy storage, thermal management and structural components.”
The research was recently published in the leading journal Science.