One-step hydrothermal growth of reduced graphene oxide/nickel hexacyanoferrate nanocomposite on Ni foam for binder-free supercapacitor electrode

Abstract

The in-situ growth of nickel hexacyanoferrate/reduced graphene oxide nanocomposite (Ni-HCF/rGO) on Ni foam was successfully achieved with a facile one-step hydrothermal method. Ni foam was not only used as the current collector but also the nickel source. By simply heating Ni foam in the aqueous solution containing graphene oxide (GO), potassium ferricyanide and P-toluenesulfonic acid (TSA), Ni-HCF/rGO nanocube arrays were synthesized on Ni foam. X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron miscroscopy (SEM) and Raman spectroscopy were used to characterize the Ni-HCF/rGO. As the supercapacitor electrode, Ni-HCF/rGO/Ni foam exhibits high capacity, long cycling life and good rate capability in 2.0 M KOH aqueous solution. An asymmetrical supercapacitor device (ASC) was assembled with Ni-HCF/rGO/Ni foam and activated carbon (AC) as the positive and negative electrodes, respectively. The fabricated ASC presents a maximum energy density of 4.38 W h m−2 at power density of 34 W m−2, suggesting its potential in practical applications.