H2O2-assisted microwave synthesis of NiO/CNT nanocomposite material for supercapacitor applications

NiO nanoflakes anchored on carbon nanotubes (CNTs) were fabricated through a H2O2-assisted microwave irradiation method. The formation of the NiO/CNT nanocomposites were characterised by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), micro Raman spectroscopy and X-ray photoelectron spectroscopy. Surface morphology studies of the prepared materials were carried out using scanning and transmission electron microscopy (SEM and TEM). The electrochemical performance of the NiO and NiO/CNTs were analysed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. GCD studies of the NiO/CNTs reveal a maximum specific capacitance of 258 F/g at 1 A/g current density in 2 M KOH aqueous electrolyte was achieved for 1:1 ratio of NiO/CNTs composite. Further, a specific capacitance of 258 F/g at 1 A/g current density obtained for 1:1 ratio of NiO/CNTs is almost 2.15 times higher than that of prepared NiO (120 F/g) which indicates an excellent synergistic effect in NiO/CNTs nanocomposite. Furthermore, the NiO/CNTs nanocomposite electrode showed outstanding cycling stability retention of 86% of the initial capacitance after 2500 cycles. Graphical abstract