Highly efficient and stable layered AgZnS@WS2 nanocomposite electrode as superior charge transfer and active redox sites for energy harvesting device

Abstract

Transition metal dichalcogenides (TMDs) are considered to be excellent candidates in energy storage applications because of their 2D structure and astonishing electrochemical features. Still, the poor stability of these materials limits their way to becoming perfect supercapattery electrode materials. Therefore, researchers are synthesizing their hybrids with other electrode materials to minimize these drawbacks. Herein, the tungsten disulfide (WS2) nanosheets were combined with hydrothermally synthesized silver zinc sulfide (AgZnS) nanostructures to design a hybrid electrode material for high-performance energy storage devices with superior charge transfer and abundant active redox sites. The highly porous structure of AgZnS@WS2 was analyzed by BET which confirmed the enhancement in ion diffusion and the reversible redox mechanism. The composite was analyzed using SEM, XRD, RAMAN, and XPS to study its morphological, structural, and compositional properties. The effect of different electrolytes was studied to estimate the electrochemical characteristics. The AgZnS electrode, upon characterization in 1 M KOH, revealed the maximum specific capacity (Qs) of 1209.06 Cg−1 at 1.8 Ag−1. While the AgZnS@WS2 hybrid electrode exhibited the Qs of 2516.58 Cg−1 at the same current density (js) benefitting from the features of both materials. The AgZnS@WS2 hybrid electrode employed in a supercapattery revealed a maximum Qs of 388.8 Cg−1 at 1.2 Ag−1. The device delivered a maximum energy density of 86.4 Wh kg−1 and a notable power density of 4987.6 W kg−1. The superb 95 % cycle stability and strong electrochemical performance of AgZnS@WS2 are the results of the highly conductive structure and synergistic effect of hybrid material for high surface area with quick ion diffusion. The astonishing features of hybrid material are suitable and encouraging for its industrial applications as supercapattery electrode material.