Brief description of research and scholarly activity
The Carbon Based Nano-Materials research group forms part of the SARChI in Carbon Technology and Materials research group which is sponsored by National research foundation (NRF) of South Africa that looks into carbon related materials at bulk and nano-structures for their application in renewable energy.
The Nano-carbon group focuses on the investigation of chemical vapor deposition (CVD) grown graphene films and 3D graphene foam (GF) based nano-composites for energy storage and sensing applications.
Firstly, the group is involved in optimizing the growth of graphene thin film to form single layer, bilayer and few layers through CVD growth. Secondly, transition metal oxides (tMOs) and hydroxides (tMHs) synthesized using different methods (solvothermal, chemical bath deposition, pulsed laser deposition etc.) and 3D graphene foam -tMOs and tMHs nano-composites are characterized as electrode materials for energy storage and sensing applications.
Bernal-stacked bilayer graphene, where half of the carbon atoms in the second layer sit on top of the empty centers of hexagons in the first layer, is an interesting material because of its tunable bandgap of up to 250 mV by an external electric field. This unique property is attractive for fundamental research as well as applications where the ability to adjust the band gap is desired, such as tunnel field-effect transistors and tunable laser diodes. CVD technique is the synthesis method of choice for this special bilayer on Cu foil. The key point for bilayer graphene growth by CVD is to overcome the self-limiting nature of single layer graphene on Cu.
Electrochemical devices (batteries and capacitors) are the most promising energy storage systems. Electric double layer capacitors (EDLCs), also known as supercapacitors or ultracapacitors, have received a great attention because they can achieve a higher energy density than conventional capacitors and a better power density than batteries. A wide variety of different electrode materials and electrolytes are currently being investigated to improve on efficiency and practicality of EDLCs. Using graphene produced by chemical vapor deposition (CVD), as reference material, graphene-based activated carbon material is produced by different procedures; from solvothermal to simple reflux. Our recent works have shown that the materials produced are good candidates for EDLC, with high micropore volume and good conductivity. Pseudocapacitive and Faradaic materials, which involve charge transfer between the electrode and electrolyte, are also explored in our group.