Each type of sulphur plays a crucial role in improving the properties of S-doped graphene. As the aromatic sulphide is electron rich, the dipole moment is enhanced upon applying electric field. As a result, the dielectric constant of the electrolyte increases. Hence the charge transfer between electrode and electrolyte is favoured and the capacitive performance of S-doped graphene is more pronounced . It has been reported in another literature that the specific capacitance of DMSO derived S-doped graphene is 261 F g -1 at 1 A g -1 in 20% KOH solution which is higher than the S-doped graphene synthesized from thioacetamide (198 F g -1 ) .