Boosting the Performance of Solid-State Symmetric Supercapacitors Using Polypyrrole-Wrapped WSe2 Nanoparticles

Abstract The polypyrrole (PPy)/tungsten diselenide (WSe2) nanoparticle (NP) composite electrode was successfully engineered through an in situ polymerization strategy, incorporating ultrasonication-assisted liquid-exfoliated WSe2 NPs with controlled loading. The formation and morphology of the nanocomposites were characterized using various experimental techniques. Transmission electron microscopy confirmed the wrapping of PPy over WSe2 NPs, while X-ray photoelectron spectroscopy verified the strong interfacial interaction between PPy and WSe2 NPs. The influence of WSe2 content on the electrochemical performance was systematically evaluated. Among the prepared electrodes, the sample containing 5 % w/v WSe2 demonstrated optimal behavior, delivering a high specific capacitance of 614.6 F g−1 at 5 mV s−1, along with exceptional cycling stability, retaining 99.97% of its capacitance after 3000 continuous cyclic voltammetry cycles. The solid-state symmetric supercapacitor fabricated with PPy/WSe2 electrodes and the PVA/LiClO4 gel electrolyte operated stably within a wide potential window of 1.6 V. The device exhibited a maximum energy density of 18.2 Wh kg−1 at a power density of 400 W kg−1, indicating a favorable balance between energy storage and power output. The enhanced performance is attributed to the synergistic interaction between conducting PPy and electroactive WSe2 NPs, which facilitates efficient charge transport and structural stability. These results establish PPy/WSe2 NP hybrid composites as promising electrode materials for high-performance next-generation supercapacitor applications.