A Nix:Vy–Se nanoparticle decorated hierarchical porous Zn–Co–P nanowire array electrode for high energy density asymmetric supercapacitors

Abstract

The design of realistic bi-metallic hybrid electrodes with high performance and rich defects for high energy density supercapacitors is greatly desired. Herein, we report a novel bi-metallic heterogeneous electrode, Ni_x:V_y–Se/Zn–Co–P NWAs, made by a simple and practical process. The Zn–Co–P NWs, as the base materials, are synthesized through a two-step process: hydrothermal reaction and phosphorization via chemical vapor deposition (CVD). The high electrochemical performance Ni_x:V_y–Se nanoparticles are uniformly deposited via a simple electrodeposition technique to form a Ni_x:V_y–Se/Zn–Co–P NWA heterogeneous porous electrode structure. Owing to the high conductivity of the bimetallic selenide nanoparticles and phosphide-based material, the optimal Ni_x:V_y–Se/Zn–Co–P NWA electrode displays enhanced specific and areal capacity. Most significantly, an asymmetric supercapacitor (ASC) assembled with Ni_x:V_y–Se/Zn–Co–P NWAs (positive electrode) and an Fe₂O₃@CNFs/N-rGO aerogel (negative electrode) exhibits a wider operating potential range of 1.7 V, a superb energy storage capacity of 123.6 W h kg⁻¹ at 1050.2 W kg⁻¹, and excellent cycling properties with a retention capacity of 95.8% after 10 000 cycles.