PVDF-Based Nanocomposites with Increased Crystallinity and Polar Phases toward High Energy Storage Performance

Poly(vinylidene fluoride) (PVDF)-based nanocomposites, despite their extensive exploration for dielectric energy storage applications, are constrained by a low intrinsic dielectric constant (εr). Traditional approaches to enhance εr by incorporating high εr ceramic fillers often compromise the electric breakdown strength (Eb), thereby limiting the overall energy storage performance. This study aims to address this dilemma by introducing a novel approach using highly dispersed modified-BaTiO3 (BTPM) nanofillers at low loadings. We elucidate the impact of these nanofillers on the crystallization behavior of PVDF-based nanocomposites and their subsequent influence on the dielectric energy storage performance. The findings reveal a remarkable enhancement in dielectric properties with only 1.72 vol % BTPM filler loading, simultaneously achieving a 1.48-fold increase in εr and a 1.23-fold improvement in Eb. This innovation overcomes the limitation of the dilemma and significantly improves the discharge energy density (Ue) to 16.27 J/cm3 and the charge–discharge efficiency (η) to 78%. These advancements are primarily attributed to the increased crystallinity and optimized ratio of polar to nonpolar phases (Fpolar/Fnon), induced by the highly dispersed BTPM nanofillers. This study not only advances the development in high-performance dielectric energy storage PVDF-based nanocomposites but also opens new avenues for future research, focusing on the synergistic enhancement of dielectric properties with minimal filler loading.