MOF-Derived Ultrathin NiCo-S Nanosheet Hybrid Array Electrodes Prepared on Nickel Foam for High-Performance Supercapacitors

Abstract

At present, binary bimetallic sulfides are widely studied in supercapacitors due to their high conductivity and excellent specific capacitance (SC). In this article, NiCo-S nanostructured hybrid electrode materials were prepared on nickel foam (NF) by using a binary metal–organic skeleton as the sacrificial template via a two-step hydrothermal method. Comparative analysis was carried out with Ni-S and Co-S in situ on NF to verify the excellent electrochemical performance of bimetallic sulfide as an electrode material for supercapacitors. NiCo-S/NF exhibited an SC of 2081 F∙g−1 at 1 A∙g−1, significantly superior to Ni-S/NF (1520.8 F∙g−1 at 1 A∙g−1) and Co-S/NF (1427 F∙g−1 at 1 A∙g−1). In addition, the material demonstrated better rate performance and cycle stability, with a specific capacity retention rate of 58% at 10 A∙g−1 than at 1 A∙g−1, and 75.7% of capacity was retained after 5000 cycles. The hybrid supercapacitor assembled by NiCo-S//AC exhibited a high energy density of 25.58 Wh∙kg−1 at a power density of 400 W∙kg−1.

Plasma Treatment on Cobalt Sulfide Nanoparticle/Nickel Foam Electrocatalysts for Hydrogen Evolution Reaction

“…Similarly, in the Ni 2p XPS spectrum (Figure c), the two peaks observed at 854 and 871 eV can be assigned to Ni 2+ species, while the other two peaks at 855 and 873 eV likely correspond to Ni 3+ states. The peak observed at 852 eV originates from metallic Ni . Furthermore, the two peaks at 165 and 167 eV in the S 2p XPS spectrum (Figure d) can be attributed to S 2p 3/2 and S 2p 1/2 , respectively, indicating the presence of terminal S 2– on the CoS sites.…”

“…The peak observed at 852 eV originates from metallic Ni. 31 Furthermore, the two peaks at 165 and 167 eV in the S 2p XPS spectrum (Figure 5d) can be attributed to S 2p 3/2 and S 2p 1/2 , respectively, indicating the presence of terminal S 2− on the CoS sites. These XPS results provide valuable information about the oxidation states and chemical composition of NF@CoS, shedding light on the surface chemistry and electronic properties of the materials.…”

Binder-Free Defective Bimetallic Metal-Organic Framework Nanostructures with Lattice Distortion as Hybrid Supercapacitor Electrodes

“…Because of their special structures, MOFs possess an ultrahigh specific surface area and pores, which supply added sites for Faraday reactions . Currently, MOFs are widely employed as precursors for the construction of porous carbon, metal oxides, or metal oxide derivatives by high-temperature calcination . However, high-temperature calcination damages the framework structure of most MOFs, significantly degrading the electrochemical properties of the final materials due to the decreased availability of active sites for Faraday reactions.…”

“…8 Currently, MOFs are widely employed as precursors for the construction of porous carbon, 9 metal oxides, 10 or metal oxide derivatives by hightemperature calcination. 11 However, high-temperature calcination damages the framework structure of most MOFs, significantly degrading the electrochemical properties of the final materials due to the decreased availability of active sites for Faraday reactions. Therefore, utilizing MOFs as electrodes must be probed for supercapacitors while avoiding complicated treatments.…”