Silver-adsorbed Ti0.87O2 nanosheets and UV irradiation synergistically improve the energy storage performance of polyvinylidene fluoride-based nanocomposites

Abstract

Polyvinylidene fluoride (PVDF) films, known for their high mechanical strength, dielectric constant, and ease of processing, have gained attention as energy storage devices. However, the increasing conduction losses in PVDF under high electric fields, mainly due to electrode-limited and bulk-limited conduction, significantly hinder energy density and efficiency improvements. A composite film composed of Ti_0.87O₂ nanosheets (TiNSs) modified with Ag nanoparticles (TiNSs@Ag NSs) and PVDF has been prepared. TiNSs@Ag nanosheets serve as physical barriers and deep traps, dissipating charge energy and inhibiting bulk-limited conduction loss. Ultraviolet (UV) irradiation was also introduced to induce polar oxygen-containing groups on polymer dielectrics to trap charges from metal electrodes, creating a built-in field that reduces electrode-limited conduction loss. This work unifies the contributions of these two factors to conduction loss, thereby fundamentally suppressing both conduction and energy losses in polymer dielectrics under high electric fields. Accordingly, the UV-irradiated PVDF composite film incorporating TiNSs@Ag nanosheets exhibits a discharged energy density of 23 J cm⁻³ and an efficiency of 67% at 650 MV m⁻¹. This work provides an effective strategy for designing polymer-based nanocomposites with significantly enhanced energy storage performance.