Engineering bismuth tungstate–polymer core–shell nanostructures for advanced pseudocapacitive energy storage

Abstract

The realization of supercapacitor systems with concurrently high energy density and power density through polymer-based composite electrodes continues to represent a major obstacle in next-generation energy storage research. Herein; a core–shell nanocomposite based on poly(1 H-pyrrole) and bismuth tungsten oxide (P1HP/BWO) is rationally designed and synthesized through a two-step approach involving combustion–reflux formation of the inorganic phase followed by in situ polymerization. Structural analysis using XRD reveals the formation of well-defined crystalline domains with crystallite size of ~ 21 nm, while X-ray photoelectron spectroscopy confirms the chemical states and successful integration of the oxide within the polymer matrix. Fourier-transform infrared spectroscopy further verifies the interfacial interactions between P1HP and BWO. Morphological investigations, including morphological scanning that demonstrate the formation of a distinctive core–shell architecture composed of semi-spherical assemblies, where BWO uniformly encapsulates P1HP cores. These structures are composed of aggregated nanoscale subunits with average dimensions of ~ 150 nm, contributing to an increased electroactive surface area and enhanced ion accessibility. Electrochemical evaluation performed in a three-electrode configuration reveals that the P1HP/BWO nanocomposite exhibits promising capacitive performance, delivering an energy density of 1.1 W h kg^–1 and a power density of 720 W kg^–1. The electrode has excellent cycling stability, retaining 99.1% of its initial performance after 1000 charge–discharge cycles. The synergistic combination of conductive polymer and metal oxide, coupled with the engineered core–shell morphology, facilitates efficient charge transport and ion diffusion. These findings highlight the potential of P1HP/BWO nanocomposites as scalable and efficient electrode materials for next-generation energy storage systems.