Three-Dimensional\nPolypyrrole-Decorated CuCo₂S₄ Nanowires Anchored\non Nickel Foam: A Promising Electrode\nfor High-Performance Supercapacitors

Abstract

The\nexploitation of high-performance supercapacitors\nis crucial\nto promote energy storage technologies. Benefiting from the three-dimensional\nconductive micronanostructures and high specific capacity of the PPy@CuCo₂S₄@NF (polypyrrole/copper cobalt sulfide/nickel\nfoam) composite electrode, this electrode exhibits a high specific\ncapacity of 1403.21 C g^–1 at 1 A g^–1 and a capacitance retention of 85.79% after 10,000 cycles at 10\nA g^–1. The assembled PPy@CuCo₂S₄@NF//AC aqueous hybrid supercapacitor (AHSC) reveals a wide operating\npotential window of 1.5 V and achieves a high specific capacity of\n322.52 C g^–1 at 1 A g^–1 and a\ncapacitance retention of 86.84% after 15,000 cycles at 10 A g^–1. The AHSC also exhibits a high power density of 733.69\nW kg^–1 at an energy density of 67.19 W h kg^–1, surpassing those of previously reported spinel-based\nsupercapacitors. Ex situ X-ray diffraction and X-ray photoelectron\nspectroscopy results show that the CuCo₂S₄ spinel\nstructure changes to CuS₂ and CoS₂ cube structures,\nand the oxidation states of Cu and Co increase during charging and\ndischarging processes. Density functional theory calculations suggest\na superior conductivity for CuCo₂S₄ compared\nto that for CuCo₂O₄, demonstrating that CuCo₂S₄ has superior electrochemical performance. These\nfindings attest to the considerable potential of the spinel materials\nfor advanced energy storage applications.