Does high sulphur coal have the potential to produce high performance - low cost supercapacitors?

The heteroatom (S, N) content of the electrode material influences supercapacitor performance. Coals, which are abundant in nature, have different heteroatom contents. Activated carbon materials were synthesised from two different demineralised coal with low and high sulphur contents using chemical activation method. The samples are characterised in terms of total surface area, pore volume and size distribution, elemental, Fourier Transform Infrared (FTIR) Spectroscopy, X-ray Photo-electron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-Ray Diffraction (XRD) analyses. The total surface areas of the samples are 934 and 1869 m(2)g(-1). While the sulphur contents of the raw coals are 12.35 % and 0.47 %, the sulphur content of the activated carbons produced from these raw materials are 3.5 % and undetectable. Supercapacitor performance is tested by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Galvanostatic Charge-Discharge (GCD) techniques. The analysis shows specific capacitances (C-cell, two-electrode cell) of 124.9 F.g(-1) and 65.1 F.g(-1) at 1 A.g(-1) current density for the activated carbons produced from low and high sulphur contents, respectively. The tests show that demineralised coal with a high natural sulphur content is an ideal raw material for producing high value added activated carbon for supercapacitors.