Preparation and properties of polyvinylidene fluoride dielectric nanocomposites for energy storage applications through synergistic addition of ionic liquid‐modified graphene oxide nanosheets and functionalized barium titanate hybrid fillers

Abstract To tackle the challenge of filler agglomeration and low interfacial bonding strength during manufacturing filled polymer dielectric nanocomposites containing graphene oxide (GO) nanosheets, the author proposed an interface design strategy based on the synergistic hybridization of ionic liquid (IL) modification and different dimensional fillers. GO nanosheets were functionalized by IL, and then polyvinylidene fluoride (PVDF) dielectric nanocomposites (GO‐ g ‐IL/PVDF) were prepared and evaluated. Based on this, hydroxylated barium titanate BT‐OH@GO‐ g ‐IL/PVDF ternary nanocomposites were further prepared. A comprehensive analysis of the morphology, mechanical, thermal, electrical, and dielectric properties of the PVDF dielectric nanocomposites was systematically conducted. The results showed that IL was successfully grafted on GO, benefiting an increase in the filler dispersion and interfacial bonding strength. GO‐ g ‐IL also promoted β ‐crystal formation of PVDF and increment of crystallinity. DSC test further revealed that the inclusion of BT‐OH@GO‐ g ‐IL as dielectric nanofillers promoted the formation of multiple crystal types in PVDF and accelerated the crystallization process. The incorporation of GO‐ g ‐IL facilitated the formation of localized conductive networks within the PVDF matrix, leading to enhanced electronic displacement polarization and an improved dielectric constant. The dielectric constants of the GO‐ g ‐IL/PVDF composites containing 2% and 8% of GO‐ g ‐IL were measured to be 24.28 and 78.46, which were found to be 2.6 and 8.4 times higher than that of pure PVDF. However, the dielectric loss also increased sharply at high nanofiller loading. The dielectric constant and loss of the BT‐OH@GO‐ g ‐IL/PVDF nanocomposites were found to be 40.32 and 0.38, with a content of 2% for GO‐ g ‐IL and 20% for BT‐OH. Highlights A facile interface design strategy based on ionic liquid (IL) integrating GO nanosheets and hydroxylated barium titanate (BT‐OH) to form BT‐OH@GO‐ g ‐IL compounding nanofiller has been proposed. PVDF dielectric nanocomposites containing BT‐OH@GO‐ g ‐IL compounding nanofiller were systematically investigated and compared. The effects of interfacial interactions between BT‐OH@GO‐ g ‐IL and PVDF contribute to the uniform dispersion and comprehensive property improvements of PVDF dielectric nanocomposites. This work provides a novel strategy for the fabrication of PVDF dielectric nanocomposites, inspiring the research and development of PVDF in the energy storage applications areas in the future.