One-step synthesis and energy-storage application of Ni–Se–S/nickel foam nanoarrays with high areal specific capacitance

Abstract

Multi-element compound nanomaterials with unique physicochemical properties have the promising prospect in the field of supercapacitors. However, multi-anionic compounds are rarely investigated compared to multi-cationic compounds. Therefore, a serial of Ni–Se–S nanorods rooted in nickel foams are successfully synthesized by the one-step solvothermal method rather than the ion exchange approach. Structural characterizations indicate that these Ni–Se–S ternary nanorods with different chemical composition form the ordered nanoarray structure. Electrochemical experimental results indicate that Ni3(Se0.3S0.7)2/nickel foam nanoarrays have the optimal properties, i.e.: high areal specific capacitance of 13.50 F cm−2, better rate capability than the controlled Ni–Se–S compounds, and good cycle stability.These excellent properties result from the ordered array structure, heterozygous chalcogen atoms, significant synergistic effect, and high conductivity. More importantly, novel battery–capacitor hybrid supercapacitors are assembled based on Ni3(Se0.3S0.7)2/nickel foam nanoarrays and active carbon. This hybrid device has a high areal energy density of 0.50 mWh cm−2, 81.96% capacitance retention rate after 10,000 cycles, and potential commercial value. All of these outstanding results demonstrate that Ni3(Se0.3S0.7)2/nickel foam nanoarrays are very promising for advanced energy-storage devices.