V2O5–PEDOT hybrid nanobelts, synthesized via sonochemical polymerization, exhibit enlarged interlayer spacing, faster ion diffusion, and enhanced conductivity. The hybrids achieve a 2.3× increase in volumetric charge storage, high coloration/bleaching efficiencies, and distinct CIELAB profiles. This work highlights the dual functionality of V2O5–PEDOT as electrochromic electrodes with superior energy storage, advancing multifunctional smart device applications.

Abstract

Electrochromic active electrodes can exhibit significant specific charge-storage capacity; however, their total stored energy is often limited by the limited thickness of the active coating. This restraint can be addressed by using layered materials capable of storing substantial amount of charge within their interlayer spaces. Various compositions of V₂O₅–PEDOT hybrid nanobelts were synthesized via an efficient sonochemical method, resulting in redox polymerization of EDOT monomers and subsequent PEDOT formation within V₂O₅ interlayers. PEDOT incorporation expanded the V₂O₅ interlayer spacing, enabling a higher diffusion coefficient, improved conductivity, faster intercalation kinetics, and enhanced charge storage. Electrodes fabricated from these hybrids demonstrated up to a 2.3-fold increase in volumetric charge storage capacity. Electrochromic devices (ECDs) constructed with these materials achieved a notable CIELAB color difference of 41.75, a peak coloration efficiency of 80 cm² C⁻¹, and a peak bleaching efficiency of 114 cm² C⁻¹. Excessive PEDOT, however, was found to reduce crystallinity, compromising charge storage and electrochromic performance.