1D interconnected porous binary transition metal phosphide nanowires for high performance hybrid supercapacitors

The one-dimensional (1D) nanostructured battery-type electrode materials are considered as a promising candidate to develop high energy hybrid supercapacitors (HSCs) owing to their reversible and abundant redox activity. Herein, we report 1D nickel cobalt phosphide (NCP) wire-like nanoarchitecture, which is prepared by hydrothermal method and subsequent phosphorization treatment. The 1D interconnected porous NCP nanowires are featured with the rich exposed redox active sites and fast charge transport pathway for high-capacity battery-type electrodes. The bimetallic NCP electrode exhibits a larger specific capacitance of 1395 F g⁻¹ than those of monometallic nickel phosphide (920 F g⁻¹) and cobalt phosphide (568 F g⁻¹) electrodes at 1 A g⁻¹. The HSCs are constructed using bimetallic 1D NCP nanowires and the activated carbon as positive and negative electrodes, respectively. The resulting HSCs deliver the improved energy density of 53.31 W h kg⁻¹ and power density of 46.53 kW kg⁻¹ along with the capacitance retention of 83.04% over 20 000 cycles.