Three dimensional hierarchical flower-like CoCuS/Co1-xCuxS electrodes for electrochemical supercapacitors

Abstract

Recently, the 2021 United nations climate change conference (COP26) have again stressed on the need of carbon neutral economy. To cope up with the power hunger of industrial and/ technological world of hybrid electric vehicles and portable electronic devices it is imperative to search the environment friendly novel materials with property tailoring abilities. In this connection, we have deposited Co1-xCuxS/CoCuS (0.025 ≤ x ≤ 0.1) thin-films via chemical route as an alternative material for supercapacitor application. To asses the suitability of as-deposited thin films, we have characterized thin films using variety of characterization techniques. X-ray photoelectron spectroscopy was used to examine and confirm the chemical states of Co, Cu, and S. Surface morphology of as-deposited CoCuS film (x = 0.075, sample-C3) showed a crumpled flower-like microstructure. Uniform distribution of hillocks and valleys was observed using atomic force microscopy. The topographical outcomes obtained from electrostatic force microscopy and Kelvin probe force microscopy confirmed that the sample-C3 (x = 0.075) is suitable for energy storage applications. Sample-C3 demonstrated excellent supercapacitive performance with a high specific capacitance of 907.55 F g−1 at 5 mV s−1, remarkable rate capability, and ~ 90% of capacitive retention after 5000 cycles in a 1 M KOH electrolyte. Better supercapacitive behavior and cycling stability of the CoCuS samples may offer a perspective for various mixed metal sulfide thin films with hierarchical architectures as an viable alternative for the efficient energy storage devices.