Hierarchical ruthenium oxide-anchored tungsten disulfide/polypyrrole ternary nanocomposites for supercapacitor electrodes: Transition toward surface-controlled charge storage

A compositionally controlled ternary polypyrrole‑tungsten disulfide‑ruthenium oxide (PPy-WS 2 -RuO 2 ) nanocomposite was synthesized using a facile in situ oxidative polymerization route for supercapacitor applications. The WS 2 content was fixed at 10 wt%, while RuO 2 loading was systematically varied (3–15 wt%) to investigate its influence on electrochemical behavior. Structural, morphological, and spectroscopic analyses indicated the formation of a ternary composite architecture, with the coexistence of PPy, WS 2 , and RuO 2 phases within the composite matrix. Electrochemical measurements in 1 M H 2 SO 4 revealed that performance varied significantly with RuO 2 loading. The optimized PWR 9 electrode exhibited a specific capacitance of 407.6 F g −1 at 0.5 A g −1 (GCD) and 239.3 F g −1 at 10 mV s −1 (CV). Kinetic investigations using b-value determination, Dunn's method, and Trasatti analysis indicated a progressive shift toward surface-controlled charge storage following WS 2 and RuO 2 incorporation. Reduced charge-transfer resistance for ternary composites was confirmed via electrochemical impedance spectroscopy. The PWR 9 electrode retained 78.3% capacitance after 5000 cycles at 5 A g −1 . In a symmetric configuration, the PWR 9 device delivered an energy density of 30 Wh kg −1 at a power density of 800 W kg −1 , with 87.7% retention after 5000 cycles. These results demonstrate that the rational design of a hierarchical ternary architecture triggers a transition from the diffusion-limited kinetics of pristine polypyrrole to a dominant surface-controlled pseudocapacitive mechanism in the optimized nanohybrid.