Simultaneous Electrochemical Exfoliation and Functionalisation of Graphene
The many characteristics of graphene make it very interesting to a wide range of industries. Currently, the lack of scalable routes to produce graphene in large enough quantities and further processing of graphene are areas that need further development.
Many industries require ultra-thin layers of graphene to confer many benefits. For example, the excellent conductance of graphene could be vital for next generation ultra-fast electronics. However, such applications require the ability to produce layers so thin that it is necessary to disperse them in a solvent. Graphene is known to have poor stability in most common solvents and can re-aggregate in such solutions. The technology described here enables the production of functionalized graphene with increased dispersibility than non-functionalized graphene through a single reaction.
A representation of simultaneous exfoliation and functionalisation of graphene. The top route shows the functionalised graphene produced via this technology, the bottom route shows traditional graphene exfoliation.
This novel technique involves the simultaneous electrochemical exfoliation and functionalisation of graphene in a single stage process, preventing re-aggregation. This technology utilises a single applied potential allowing for functionalisation with diazonium compounds whilst simultaneously exfoliating with Cs+ or tetraalkylammonium cations. Diazonium compounds were chosen to functionalise graphene due to their versatility and ability to be further functionalised easily.
- This technique produces graphene that is functionalised at the edge sites, preventing damage of the basal plane, retaining the physiochemical properties of pristine graphene.
- The functionalised graphene produced was found to be more dispersible and able to form stable dispersions of graphene in water and isopropanol mixture, with concentrations of two orders of magnitude higher than unfunctionalised graphene.
- The functionalised graphene exhibited more than 3x specific capacitance than unfunctionalised graphene, demonstrating a promising material to use in supercapacitors.
- The diazonium salt can be easily altered to suit the final uses of the graphene flakes, opening the possibility of many potential end applications.
- Dispersal of graphene onto surfaces can confer many benefits, such as increasing thermal conductivity, reducing friction, acting as a protective barrier, the production of thin films that have many applications including anti-bacterial sheets and electronic devices.
- Functionalised graphene has been shown to have higher capacitance than unfunctionalised graphene, therefore it is a promising material to use in supercapacitors.
- The technique could be adapted to produce composites for many applications.
- The technology could be applied to solar energy harvesting applications, suspended in liquids designed to filter and absorb energy from the sun.
A patent application has been filed.
1. Andinet Ejigu, Ian Kinloch, and Robert Dryfe. ACS Appl. Mater. Interfaces, 2017, 9 (1), pp 710–721. DOI: 10.1021/acsami.6b12868
Seeking collaboration partners to develop the technique further.
Dr Siobhan Daniels
IP Development and Partnering Manager – Graphene
T: +44 (0)161 306 8813