Balakrishanan Saravanakumar

In this study, pristine WO3 nanoparticles and additive-modified WO3 nanoparticles incorporating the polymers poly(vinyl alcohol) (PVA), polyethylene glycol (PEG), poly(vinylpyrrolidone) (PVP), and the organic acid p-toluenesulfonic acid (PTSA) were synthesized via the co-precipitation method. Structural analysis confirmed the formation of crystalline WO3 with crystallite sizes ranging from 42 to 54 nm, while FTIR and Raman spectroscopy revealed strong interactions between the additives and the WO3 lattice. SEM and EDX analyses demonstrated that additive incorporation transformed the morphology from agglomerated particles to porous, well-defined nanostructures with improved elemental distribution. Optical studies showed absorption edges in the range of 324–338 nm, tunable optical band gaps of 2.47–2.69 eV, and Urbach energies of 0.543–0.938 eV, indicating defect-controlled optical behaviour. Photoluminescence spectra exhibited broad emission bands (361–541 nm), which were attributed to defect-mediated charge carrier recombination. Electrochemical investigations revealed significantly improved supercapacitive performance for the additive-modified WO3 electrodes, with the W–PTSA sample exhibiting the highest specific capacitance of 258 F g−1 at a current density of 1.5 A g−1, excellent capacitance retention of 84% after 2500 charge–discharge cycles, and a low charge-transfer resistance of approximately 1.8 Ω. The enhanced electrochemical performance is attributed to improved ion transport, increased electroactive surface area, and favourable interfacial interactions introduced by the additives. These findings demonstrate that additive-assisted WO3 nanostructures are promising electrode materials for high-performance supercapacitor applications.

Electrospun Cr ₂ CT _x /carbon nanofibers were developed and investigated for supercapacitor applications, delivering a high specific capacitance of 338.8 F g ⁻¹ along with outstanding energy and power densities in an asymmetric device.