Unveiling the synergistic enhancement of electrochemical and dielectric properties in SnWO4-based heterostructures with TiO2 and MoO3 prepared by the green synthesis method

Abstract

This work investigates the structural, electrochemical, and dielectric characteristics of SnWO₄@TiO₂ and SnWO₄@MoO₃ heterostructures to evaluate the effect of TiO₂ and MoO₃ incorporation on SnWO₄-based composites for supercapacitor applications. XRD analysis confirmed the formation of crystalline heterostructures, with SnWO₄@MoO₃ exhibiting a smaller average crystallite size (26.7 nm) than SnWO₄@TiO₂ (33.3 nm), lower crystallinity (54.61% vs. 76.48%), and increased d-spacing (3.19 nm vs. 3.17 nm). BET measurements revealed a higher surface area (37.12 m²/g) and larger pore radius (13.74 nm) for SnWO₄@MoO₃, favoring ionic transport. Electrochemical testing showed that SnWO₄@MoO₃ delivered a higher specific capacitance (606 F/g at 0.8 A/g) and energy density (43.77 Wh/kg) compared to SnWO₄@TiO₂ (292 F/g, 21.12 Wh/kg). Enhanced dielectric constant, lower charge transfer resistance (2.49 Ω), and higher ion diffusion coefficient (6.43 × 10⁻⁴ cm²/s) further demonstrated improved charge storage kinetics. These synergistic improvements make SnWO₄@MoO₃ a promising candidate for high-performance energy storage devices.