Thermal Effects on the Dielectric Features of PVDF/GO/MoS 2 Hybrid Films

This study examines the temperature and frequency dependency of the dielectric characteristics of ternary polyvinylidene fluoride (PVDF) nanocomposites containing graphene oxide (GO) and molybdenum disulfide (MoS 2 ) nanofillers. Flexible films of PVDF/GO/x wt% MoS 2 (x = 0, 0.25, 0.5, 1) were synthesized using a solution casting method. Structural and morphological investigations validated the successful incorporation of both fillers. Dielectric spectroscopy over an extensive frequency and temperature spectrum revealed that the real permittivity (ε′) markedly increased at low frequencies and high temperatures, attaining approximately 163 at 100 Hz and 353 K for the PVDF/GO composite, a substantial improvement from around 53 for pure PVDF at 303 K. The addition of 0.25 wt% MoS 2 diminished the dielectric loss ( ε ″) by almost 70% in comparison to the binary PVDF/GO composite at 1 kHz and 353 K. The PVDF/GO/0.25 wt% MoS 2 sample attained the maximum energy density of 18.8 J cm −3 at 353 K and low frequency. The AC conductivity adhered to Jonscher’s power law, and impedance analysis demonstrated that GO diminished bulk resistance (from 82 × 10 6 Ω to 38 × 10 6 Ω), whereas MoS 2 elevated interfacial resistivity. The findings underscore the synergistic function of GO in augmenting interfacial polarization and MoS 2 in mitigating dielectric loss, resulting in a composite that achieves an ideal equilibrium of elevated permittivity and minimal loss. This customized performance establishes PVDF/GO/MoS 2 hybrid films as viable dielectrics for high-temperature flexible energy storage applications, such as capacitors for wearable electronics and low-loss parts in next-generation flexible electronics.