Controllable Synthesis of complex nickel-vanadium selenide three dimensional flower-like structures as an attractive battery-type electrode material for high-performance hybrid supercapacitors

Abstract Binary metal selenide-based electrodes with absorbing structures are gaining wide attention in energy storage technology, ascribing to the excellent electrical conductivity, outstanding charge storage performance and a low band gap of these electrodes. Herein, a novel three dimensional (3D) flower-like Ni-V-Se composite was established by the hydrothermal method and vertically grew on reduced graphene oxide/Ni foam (rGO/NF) with tunable composition and morphologies. With the increase of selenization time, the morphology of composites is gradually incorporated from the nanosheets into nano-flowers and finally aggregates into large nanoparticles. The prepared optimal sample (NiVSe-6h) shows a palmary specific capacity of 1197.6 C g−1 at a current density of 1 A g−1, and stable long-term cycling performance (89.4% retention after 8000 successive charge-discharge cycles at 10 A g−1). The established NiVSe-6h//AC device uses NiVSe-6h and AC as the positive electrode and negative electrode, which obtains a large specific capacity of 225.1 C g−1 at 1 A g−1 and the high energy density of 53.1 Wh kg−1 at power density of 878.5 W kg−1. Meanwhile, the device exhibits notable cycle stability (94.4%) after 6000 charge discharge cycles. These superior electrochemical behaviors of NiVSe-6h composite indicate their possible utilization as electrodes for storage devices and energy conversion.