Facile binder-free hydrothermal synthesis of NiCo₂O₄ using different reagents: a study as efficient supercapacitor...

In the present study, mesoporous NiCo₂O₄ nanomaterials were successfully synthesized on nickel foam using an eco-friendly, facile, cost-effective and reagent-assisted hydrothermal method. The physico-chemical properties were analyzed by XRD, RAMAN, FTIR and FE-SEM characterization and results confirmed the formation of NiCo₂O₄ nanoparticles. By employing cetyltrimethyl ammonium bromide (CTAB) and NH₄F as auxiliary reagents, two different samples were synthesized and the resulting NiCo₂O₄ nanoneedle arrays achieved, efficient charge transport, excellent specific capacitance (357 F/g at 1 A/g current density for NCO-N and 403 F/g at 1 A/g for NCO-C), good energy and power density and strong rate capability. Electrodes were synthesized by applying these materials on nickel foam (1 × 1 cm²) and underwent electrochemical characterizations. An asymmetric supercapacitor was fabricated using NCO-C as positive electrode and Typha Angustifolia activated carbon (TAC) as negative electrode in 2 M KOH electrolyte. The device exhibited high energy density of 33.22 Wh/kg and power density of 400 W/kg at 0.2 A/g. A good capacitance retention of 92.83% after 5000 charge-discharge cycles at 0.2 A/g current density was achieved.