Interface-Engineered Polypyrrole/WS2 Heterostructures for High-Voltage Symmetric Supercapacitors

Abstract

Aqueous electrolytes in supercapacitors are constrained by a narrow operating voltage window, limiting energy density and practical applicability thereof. To overcome this, organic electrolytes offer a promising approach to achieve higher operating voltages while maintaining excellent energy and power densities. The current study focuses on the employability of LiClO4 in a propylene carbonate:ethylene carbonate:ethyl acetate electrolyte with interface-engineered tungsten disulfide (WS2) nanoparticles (NPs) embedded in polypyrrole (PPy) via a facile in-situ route with varying WS2 NP loadings (5 and 10 wt %) to elucidate their influence on the electrochemical performance and widen the potential window in a symmetric liquid-configured prototype device. The structure and morphology of the heterostructures were systematically examined through various analytical tools. The PPy/WS2 heterostructure electrode containing WS2 NPs with a loading of 5 wt % exhibits the optimal performance, delivering a specific capacitance of 231.7 F g–1 at a sweep rate of 5 mV s–1. The symmetric device achieved a high operating voltage of 2.4 V, corresponding to 32 Wh kg–1 energy density and 1221.7 W kg–1 power density at 1 A g–1, along with 79% sustainability for 10,000 charge–discharge cycles. Furthermore, the successful operation of an LED panel and a small DC fan highlights the practical applicability of the assembled prototype.