Effect of the graphite electrode material on the characteristics of molten salt electrolytically produced carbon nanomaterials

The electrochemical erosion of a graphite cathode during the electrolysis of molten lithium chloride salt may be used for the preparation of nano-structured carbon materials. It has been found that the structures and morphologies of these carbon nanomaterials are dependent on those of the graphite cathodes employed. A combination of tubular and spherical carbon nanostructures has been produced from a graphite with a microstructure of predominantly planar micro-sized grains and a minor fraction of more irregular nano-sized grains, whilst only spherical carbon nanostructures have been produced from a graphite with a microstructure of primarily nano-sized grains. Based on the experimental results, a best-fit regression equation is proposed that relates the crystalline domain size of the graphite reactants and the carbon products. The carbon nanomaterials prepared possess a fairly uniform mesoporosity with a sharp peak in pore size distribution at around 4 nm. The results are of crucial importance to the production of carbon nanomaterials by way of the molten salt electrolytic method.

► Carbon nanomaterials are synthesised by LiCl electrolysis with graphite electrodes.
► The degree of crystallinity of graphite reactant and carbon product are related.
► A graphite reactant is identified that enables the preparation of carbon nanotubes.
► The carbon products possess uniform mesoporosity with narrow pore size distribution.