Surface‐Confined Winding Assembly of SiO₂ on the Surface of BaTiO₃ Leading to Enhanced Performance of Dielectric Nanocomposites

Abstract In response to the demand for miniaturization and lightweighting in the electronics industry, achieving enhanced energy density of dielectrics is crucial. Constructing nanocomposites consist of ceramic fillers and polymer matrix is an effective strategy in this regard. To address the adverse coupling between polarization and breakdown strength of the nanocomposites, a series of BaTiO 3 @SiO 2 nanofillers with customizable SiO 2 shell coverage degrees (90°, 180°, and 360°) is designed and synthesized by surface‐confined winding assembly of SiO 2 on the surface of BaTiO 3 . When a half area of BaTiO 3 core is coated by SiO 2 layer, it is defined as 180°. A larger coverage degree implies better reduction of leakage current injection, and more effective suppression of local electric field concentration. However, it also leads to a more pronounced reduction in the polarization. 180° BaTiO 3 @SiO 2 demonstrates the most effective mitigation of the adverse coupling between polarization and breakdown strength in nanocomposites. The 180° BaTiO 3 @SiO 2 /Poly(vinylidene fluoride) (PVDF) nanocomposite achieves high breakdown strength while maintaining relatively higher polarization intensity, for example, the energy density reaches 20.64 J cm −3 at 650 MV m −1 , which is 2.62 times of pure PVDF. This work reveals the growth mechanism of customizable SiO 2 shell coverage degrees on BaTiO 3 surfaces, providing an effective strategy for high‐performance dielectrics