Electrochemical Characterisation of Poly(aniline-co-N-methylaniline) and Poly(aniline-co-N-ethylaniline) Films on Pencil Graphite Electrode for Supercapacitor Applications

In this work, poly(aniline-co-N-methylaniline) (co-PNMA) and poly(aniline-co-N-ethylaniline) (co-PNEA) have been electrochemically synthesised on pencil graphite electrode (PGE) surface to use as an electrode material for supercapacitors. The films have been formed from aqueous solution of monomers and sulfuric acid as electrolyte. The copolymer films have been characterised by cyclic voltammetry (CV), Mott-Schottky (MS) analysis, and scanning electron microscopy (SEM). The electrochemical storage properties of uncoated electrode and copolymer coated electrodes (PGE/co-PNMA and PGE/co-PNEA) have been investigated via CV, electrochemical impedance spectroscopy (EIS), and repeating chronopotentiometry (RCP) methods in 0.100 M H2SO4 solution. Experimental results indicate that PGE/co-PNMA exhibits higher specific capacitance than PGE/co-PNEA. Highest specific capacitance values of the PGE/co-PNMA and PGE/co-PNEA have been obtained as 213.85 mF g(-1) (17.7 mF cm(-2)) and 48.60 mF g(-1) (4.36 mF cm(-2)) at 50 mV s(-1), respectively when compared with that of uncoated PGE which is 1.63 mF g(-1) (0.14 mF cm(-2)). Charge-discharge characteristics of the electrodes have shown that both of the electrodes can be used as supercapacitor electrode active materials for low voltage (<10 V) applications.