PVDF-Based Nanocomposites\nwith Increased Crystallinity\nand Polar Phases toward High Energy Storage Performance

Poly(vinylidene fluoride) (PVDF)-based nanocomposites,\ndespite\ntheir extensive exploration for dielectric energy storage applications,\nare constrained by a low intrinsic dielectric constant (ε<sub>r</sub>). Traditional approaches to enhance ε<sub>r</sub> by\nincorporating high ε<sub>r</sub> ceramic fillers often compromise\nthe electric breakdown strength (<i>E</i><sub>b</sub>),\nthereby limiting the overall energy storage performance. This study\naims to address this dilemma by introducing a novel approach using\nhighly dispersed modified-BaTiO<sub>3</sub> (BTPM) nanofillers at\nlow loadings. We elucidate the impact of these nanofillers on the\ncrystallization behavior of PVDF-based nanocomposites and their subsequent\ninfluence on the dielectric energy storage performance. The findings\nreveal a remarkable enhancement in dielectric properties with only\n1.72 vol % BTPM filler loading, simultaneously achieving a 1.48-fold\nincrease in ε<sub>r</sub> and a 1.23-fold improvement in <i>E</i><sub>b</sub>. This innovation overcomes the limitation\nof the dilemma and significantly improves the discharge energy density\n(<i>U</i><sub>e</sub>) to 16.27 J/cm<sup>3</sup> and the\ncharge–discharge efficiency (η) to 78%. These advancements\nare primarily attributed to the increased crystallinity and optimized\nratio of polar to nonpolar phases (<i>F</i><sub>polar</sub>/<i>F</i><sub>non</sub>), induced by the highly dispersed\nBTPM nanofillers. This study not only advances the development in\nhigh-performance dielectric energy storage PVDF-based nanocomposites\nbut also opens new avenues for future research, focusing on the synergistic\nenhancement of dielectric properties with minimal filler loading.