Free-standing Ni3(VO4)2 nanosheet arrays on aminated r-GO sheets for supercapacitor applications

Abstract

Ni₃(VO₄)₂ nanosheet arrays are grown on aminated r-GO sheets through a facile hydrothermal route. The growth of Ni₃(VO₄)₂ nanosheet arrays on aminated r-GO sheets (NiV@r-GO nanocomposites) is confirmed by XRD, FESEM, TEM, XPS, and Raman spectroscopy. The length, height and thickness of the Ni₃(VO₄)₂ nanosheet arrays are ∼100, ∼20 and ∼10 nm, respectively. The density of the Ni₃(VO₄)₂ nanosheet arrays on the r-GO sheets is directly related to the concentration of precursor used. The generation of mesoporosity during synthesis originates from the high surface area in the NiV@r-GO nanocomposites. The high surface area causes the mesoporous NiV@r-GO nanocomposite based electrode to exhibit a specific capacity of 170 C g⁻¹ at 0.5 A g⁻¹, which is approximately three times higher than that of aminated r-GO sheets. The capacity retention of the NiV@r-GO nanocomposite is 97.2% at 0.5 A g⁻¹ current density after 1400 cycles. Other than the faradic redox reaction, the superior electrochemical performance of NiV@r-GO nanocomposites over the aminated r-GO sheet based electrode is related to the three-dimensional (3D) morphology as an effect of the Ni₃(VO₄)₂ nanosheet array, which results in a higher surface area, more active sites and greater electrolyte penetration in the electrode.