Ni3Se2 nanosheets in-situ grown on 3D NiSe nanowire arrays with enhanced electrochemical performances for supercapacitor and efficient oxygen evolution

A typical core-branch NiSe@Ni3Se2/NF nanostructure directly grown on Ni foam as an asymmetric supercapacitor (ASC) electrode and electrocatalyst is prepared employing a facile two-step in-situ growth procedures. The as-synthesized nanoarchitecture is composed of relatively thin Ni3Se2 nanosheets shell and NiSe nanowire arrays core (NiSe NWAs). Thanks to the favorable electric conductivity, high theoretical capacitance and the distinct micro-morphologies of the Ni-based selenide, it can present excellent capacitive performances. More importantly, an ASC constructed utilizing the as-fabricated NiSe@Ni3Se2/NF hybrids as positive electrode and active carbon (AC) as negative electrode can exhibit a large energy density of 45.5 Wh kg−1 at 1.600 kW kg−1. Moreover, it can also show outstanding ultra-long durability with a capacitance retention of ~96.1% after 12,000 cycles. In addition, the as-obtained NiSe@Ni3Se2 catalyst can present favorable electrocatalytic performances for oxygen evolution reaction (OER) with a small overpotential of 281 mV at 10 mA cm−2. Thus, this strategy not only provides an efficient channel to design high-performance electrode materials and electrocatalyst, but also promotes the practical applications of the newly emerged metal selenides nanoarchitectures in energy storage and conversion systems. © 2020 Elsevier Inc.