Rich-grain-boundary of Ni3Se2 nanowire arrays as multifunctional electrode for electrochemical energy storage and conversion applications†
Controllable nanoarchitecture arrays of the transition metal selenide, supported on conductive substrates, are promising materials for high-performance electrochemical energy storage and conversion applications. Herein, Ni3Se2 nanowire arrays with a rich-grain-boundary are rationally grown on a nickel foam (NF) substrate by the solvothermal method. Under optimized conditions, the Ni3Se2 nanowire arrays prominently display high areal capacitance of 635 μA h cm−2 at a current density of 3 mA cm−2 and excellent rate capability. As an asymmetric supercapacitor, the Ni3Se2 electrode (cathode) shows a high energy density of 42.6 W h kg−1 at a power density of 284.8 W kg−1. When used as a two-dimensional (2D) electrode for water splitting reaction, the Ni3Se2 electrode exhibits high catalytic activity to achieve 100 mA cm−2 at an overpotential of 320 mV in the oxygen evolution reaction and a low overpotential of 95 mV at a current density of 50 mA cm−2 in the hydrogen evolution reaction in a 1.0 M KOH solution. The Ni3Se2 nanowire array electrode is shown to be a high-performance alkaline water electrolyzer with current density of 10 mA cm−2 at a cell voltage of 1.62 V. The results demonstrate Ni3Se2 as a promising 2D highly active electrode for electrochemical energy storage and conversion applications.