WO3 integrated with carbon and rGO networks: Correlating morphology, structural strain, and charge-storage mechanisms

This study presents a systematic comparison of twelve WO 3 -carbon and WO 3 -rGO nanocomposites synthesized through controlled co-precipitation and autoclave-assisted crystallization to unravel the structural and electrochemical mechanisms governing charge storage behaviour. XRD coupled with Debye-Scherrer (DS), Williamson-Hall (W-H), and Size-Strain (SS) analyses reveals that crystallite broadening in these systems is dominated by anisotropic microstrain, strongly influenced by carbon-matrix chemistry and synthesis route. FESEM demonstrates distinct morphological regimes, ranging from flower-like WO 3 assemblies to sheet-like rGO-supported frameworks, while FTIR and UV-Vis confirm bonding evolution and band-gap modulation across the series. Electrochemical measurements highlight pronounced differences in charge-storage performance. Among all samples, CWO-1P exhibits the highest initial capacitance, delivering 78.56 Fg −1 (8.02 mF cm −2 ) at 20 mV s −1 and 15.12 Fg −1 at 0.5 Ag −1 due to its optimally dispersed WO 3 nanodomains and carbon-assisted pseudocapacitive activity. RWO-1A exhibits comparatively favourable CV-based cycling retention (92%) among the investigated samples under the present 100-cycle conditions. Nyquist analysis further confirms improved charge-transfer kinetics in rGO-rich architectures. The combined insights establish a clear structure-strain-capacitance correlation and identify the optimal compositions for electrochemically active supercapacitors. The combined structural and electrochemical results reveal that morphology, crystallographic strain, conductive-matrix interactions, and phase characteristics collectively influence the charge-storage behaviour of the WO 3 -based composites. Rather than identifying a single dominant structural parameter, the study highlights the coupled effects of microstructural and interfacial characteristics on capacitive and pseudocapacitive performance. This work provides a rational framework for engineering WO 3 -based electrodes with tuneable capacitive and pseudocapacitive characteristics for next-generation energy-storage technologies.