Preparation of pitch-based carbon materials using a template and an orthogonal array design for super capacitors

Abstract

Coal tar pitches (CTPs) are used as a supercapacitor precursor because they are of low cost and produce high carbon yields. In this reported work, a simple and feasible method for the fabrication of pitch-based carbon electrode materials with high capacitance was established using nanosized oxides as a template and the potassium hydroxide (KOH) activation method. The preparation conditions were optimised using an orthogonal array design. The electrochemical performance of the electrode materials was examined by constructing a single electrode capacitor in 6 mol l-1 KOH electrolyte; specific surface area was determined by N2 adsorption-desorption analysis and textural characterisation was conducted by transmission electron microscopy. Results showed that the synthetic carbon material possessed the highest iodine adsorption value of 2238 mg g-1 under optimum conditions (Al2O3 used as the template, an activation temperature of 700°C and a CTP/template mass ratio of 1:1), a high capacitance of 258 F g-1 at a current density of 0.5 A g-1 and good cycle stability.