We report enhancement of the dielectric permittivity of poly(vinylidene fluoride) (PVDF) generated by depositing magnetic iron oxide (Fe3O4) nanoparticles on the surface of barium titanate (BT) to fabricate BT–Fe3O4/PVDF composites. This process introduced an external magnetic field and the influences of external magnetic field on dielectric properties of composites were investigated systematically. The composites subjected to magnetic field treatment for 30 min at 60 °C exhibited the largest dielectric permittivity (385 at 100 Hz) when the BT–Fe3O4 concentration is approximately 33 vol.%. The BT–Fe3O4 suppressed the formation of a conducting path in the composite and induced low dielectric loss (0.3) and low conductivity (4.12 × 10−9 S/cm) in the composite. Series-parallel model suggested that the enhanced dielectric permittivity of BT–Fe3O4/PVDF composites should arise from the ultrahigh permittivity of BT–Fe3O4 hybrid particles. However, the experimental results of the BT–Fe3O4/PVDF composites treated by magnetic field agree with percolation theory, which indicates that the enhanced dielectric properties of the BT–Fe3O4/PVDF composites originate from the interfacial polarization induced by the external magnetic field. This work provides a simple and effective way for preparing nanocomposites with enhanced dielectric properties for use in the electronics industry.

High dielectric permittivity and low dielectric loss of CCTO–Fe3O4/PI composites were obtained at low filler loading induced by magnetic field.

Composites that possess ultra-high breakdown strength together with high dielectric constant have always been the pursuit of energy storage polymer-based dielectric. However, the constrained relationship between them makes uniform filled...

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At present, dielectric capacitors have revealed large potential in the field of dielectric energy storage thanks to their advantages such as easy processing, flexibility, and long service life. Currently, a variety of methods have been proposed to prepare composite dielectrics with excellent comprehensive performance, which have the characteristics of great insulation strength, good flexibility, excellent efficiency, and large energy storage density. In this research, three composite dielectrics such as BT/PESU, BN/PESU, and TiO2/PESU are prepared by the solution casting method. Herein, we report that the incorporation of low contents of inorganic fillers into a linear polymer leads to concurrent enhancements in both permittivity and breakdown strength. The composite material is conducive to the lightweight nature and miniaturization of dielectric capacitors and at the same time promotes the development of electrical energy storage and conversion devices. The linear dielectric material polyethersulfone (PESU) is selected as the matrix, and it is planned to retain the characteristics of excellent insulation strength and small tanδ of PESU. In addition, by introducing inorganic filler phases with different particle sizes and dielectric constants, the microstructure of the composite material can be adjusted and the macroscopic properties of the composite material can be improved. At last, through comparison, a polymer-based dielectric composite with excellent breakdown strength and energy storage performance was successfully achieved. Fortunately, the discharge energy density of the 1 wt % TiO2/PESU dielectric composite reaches 7 J/cm3 at 570 kV/mm, and its charge–discharge efficiency reaches 87%. This work paves a broad road for the research and development of energy storage materials in the field of dielectric capacitors with high energy storage density, high efficiency, and excellent breakdown strength.

With the increasingly high requirements for wearable and flexible devices, traditional inorganic capacitors cannot meet the flexible demand of next-generation electronic devices. In this work, the energy storage property of all-inorganic flexible films has been systematically studied. PbZrO3 (PZO) and Al2O3 (AO) are selected as the antiferroelectric layer and insulating layer, respectively. The heterostructured films are prepared on the fluorphlogopite (F-Mica) substrate by chemical solution deposition. The microstructure, polarization behavior, and energy storage performances are investigated. The results demonstrate that the AO/PZO/AO/PZO/AO (APAPA) multilayered thin film possesses a greatly improved energy storage density (W rec) of 28.1 J/cm3 with an excellent energy storage efficiency (η) of 80.1%, which is ascribed to the enhanced breakdown strength and large difference in polarization. Furthermore, the capacitive films exhibit good stability under a wide working temperature range of 25–140 °C and an electric fatigue endurance of 107 cycles. Besides, the energy storage performances are almost unchanged after 104 bending cycles, demonstrating an excellent mechanical bending endurance. This work sheds light on the preparation technology and improvement of the dielectric energy storage performance for all-inorganic flexible multilayered thin films.

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In this paper, t mol% Nb2O5 doped x(Ba0.7Ca0.3)TiO3-(1-x)Ba(Zr0.2Ti0.8)O3[xBCT-(1-x)BZT-t mol% Nb2O5] lead-free piezoelectric ceramics were prepared successfully using a solid-state reaction technique. Firstly, the phase transition ofxBCT-(1-x)BZT ceramics were investigate, and it was found that 0.47BCT-0.53BZT sample shows a rhombohedral (R)-tetragonal (T) phase transition at room temperature near Morphotropic Phase Boundary and presents better ferroelectric and piezoelectric properties compared with the other component ceramics. On this basis, the crystal structure, surface morphologies and electrical properties of the Nb2O5 doped 0.47BCT-0.53BZT ceramic were studied in detail. It was found the grain size increases monotonously and the microstructure become more denser and homogeneous when Nb-doping concentration increases above t=0.3, and a maximum strain value of 0.132%