Tailoring the interface magnetron sputtered silver/tungsten disulfide for battery-supercapacitor hybrids: Electrochemical assessment of redox activity

Abstract

The emergence of two-dimensional transition metal dichalcogenides as a promising material has attracted significant interest in its potential applications. Also, there is a dire need to explore binder-free routes to fabricate electrodes for enhanced energy storage performance. In this study, tungsten disulfide (WS2) films of varying thicknesses were magnetron sputtered onto nickel foam with silver serving as an interface layer for use in a variety of energy storage applications. Using atomic force microscopy, Raman spectroscopy, X-ray diffraction, and the surface and structural characteristics are explored. The Ag/WS2 electrodes were initially evaluated electrochemically in a standard three-electrode cell configuration to identify the best performing sample. By combining the most superior electrode with activated carbon (AC), a hybrid supercapacitor device (Ag/WS2//AC) was assembled. A maximum energy density of 56.5 Wh kg−1 and 4000 W kg−1 power density was displayed by the hybrid device, with remarkable long-term cyclic stability. Calculating the ‘k’ regression coefficients and separating the capacitive-diffusive current contribution were accomplished using Dunn's model. The superior outcomes of Ag/WS2 may enable their integration into advance energy storage devices of the future.