Hierarchical ternary Ni–Co–Se nanowires for high-performance supercapacitor device design

Abstract

Large-scale uniform Ni–Co–Se bimetallic ternary nanowires have been successfully synthesized through a successive cation exchange. First, NiSe nanowires in situ grown on nickel foam (NF) were prepared by a facile solvothermal route. Next, a series of ternary materials possessing different proportions of Ni and Co were fabricated by a Co-exchange method using the Ni@NiSe material as a template, which effectively achieved morphological inheritance from the parent material. To explore the electrochemical performance, all synthetic materials were assembled into asymmetric supercapacitor devices. Among asymmetric supercapacitor devices, the Ni@Ni_0.8Co_0.2Se//active carbon (AC) device exhibited a high specific capacitance of 86 F g⁻¹ at a current density of 1 A g⁻¹ and excellent cycling stability with virtually no decrease in capacitance after 2000 continuous charge–discharge cycles. This device still delivered an energy density of 17 Wh kg⁻¹ even at a high power density of 1526.8 W kg⁻¹. These superior electrochemical properties of Ni@Ni_0.8Co_0.2Se as an electrode material for supercapacitor devices confirmed the synergistic effect between Co and Ni ions, suggesting their potential application in the field of energy storage.