Magnetic Field Induction ZnFe₂O₄@Carbon for Construction of a PVDF‐HFP‐Based 3D Dielectric Network

Functional fillers in the polymerization system cannot be arranged in an orderly manner when exposed to natural conditions. The application of magnetic fields in the material preparation process has been shown to greatly enhance the distribution of functional fillers, leading to the organized alignment of functional fillers and the production of polymer matrix composites with remarkable characteristics. In this experiment, rod‐like ZnFe 2 O 4 was synthesized by reverse microemulsion method, and amorphous carbon was coated on the surface of ZnFe 2 O 4 by freeze‐drying method to obtain ZnFe 2 O 4 @Carbon core‐shell particles. The composite films were prepared by dispersing ZnFe 2 O 4 with different volume contents into P(VDF‐HFP) matrix. The external parallel magnetic field was used to manipulate the ZnFe 2 O 4 @C/P(VDF‐HFP) composite film during the hot‐pressing process, resulting in an oriented ZnFe 2 O 4 @C/P(VDF‐HFP) composite film. The experiment revealed that when ZnFe 2 O 4 @C is aligned with the film orientation, the dielectric constant of the composite film is 50(50 Hz), which is 130 % higher than that of the unoriented composite film and 290 % higher than that of pure P(VDF‐HFP). When the filling amount is 40 Vol.%, the energy storage density of ZnFe 2 O 4 @C/P(VDF‐HFP) composite film is 1.18 times higher than that of unoriented composite material and 1.32 times higher than that of pure P(VDF‐HFP).