Poly(o-toluidine)/multiwalled carbon nanotube-based nanocomposites: An efficient electrode material for supercapacitors

We report high-performance symmetric supercapacitors from poly(o-toluidine) (POT)/multiwalled carbon nanotubes (MWCNTs) composite. POT/MWCNTs composites with varying MWCNTs concentration are produced via in situ polymerization. Performance of supercapacitor is analyzed with sulfuric acid (H 2 SO 4 ) as electrolyte and POT/MWCNTs nanocomposite as symmetrical electrodes. Nanocomposite offers synergistic combination of electrostatic double-layer charge storage of MWCNTs and pseudocapacitance of POT, demonstrating enhanced electrochemistry. The possible interactions between MWCNTs and POT are analyzed via Raman and FTIR spectroscopies. SEM results confirm coating of POT over nanotubes’ surface and possible tunneling paths between adjacent MWCNTs and POT. The specific capacitance is calculated from both cyclic voltammetry ( C sp = 459 F g −1 ) and galvanostatic charging–discharging ( C d = 339 F g −1 ). Interestingly, C d increases from 339 (initial value) to 350 F g −1 after 20 cycles, attributable to improved interfacial kinetics. Further, cell offers specific energy and power densities of 19.6 Wh kg −1 and 271 kW kg −1 , respectively, with excellent cyclability (~ 12.4% capacitance decay over 2000 cycles) and Coulombic efficiency (~ 98 to 101%). Graphic abstract