Improving Dielectric Properties of PVDF Composites by Employing Surface Modified Strong Polarized BaTiO₃ Particles Derived by Molten Salt Method

Abstract

BaTiO3/polyvinylidene fluoride (BT/PVDF) is the extensive reported composite material for application in modern electric devices. However, there still exists some obstacles prohibiting the further improvement of dielectric performance, such as poor interfacial compatibility and low dielectric constant. Therefore, in depth study of the size dependent polarization and surface modification of BT particle is of technological importance in developing high performance BT/PVDF composites. Here, a facile molten-salt synthetic method has been applied to prepare different grain sized BT particles through tailoring the calcination temperature. The size dependent spontaneous polarizationof BT particle was thoroughly investigated by theoretical calculation based on powder X-ray diffraction Rietveld refinement data. The results revealed that 600 nm sized BT particles possess the strong polarization, ascribing to the ferroelectric size effect. Furthermore, the surface of optimal BT particles has been modified by water-soluble polyvinylprrolidone (PVP) agent, and the coated particles exhibited fine core-shell structure and homogeneous dispersion in the PVDF matrix. The dielectric constant of the resulted composites increased significantly, especially, the prepared composite with 40 vol % BT loading exhibited the largest dielectric constant (65, 25 °C, 1 kHz) compared with the literature values of BT/PVDF at the same concentration of filler. Moreover, the energy storage density of the composites with tailored structure was largely enhanced at the low electric field, showing promising application as dielectric material in energy storage device. Our work suggested that introduction of strong polarized ferroelectric particles with optimal size and construction of core-shell structured coated fillers by PVP in the PVDF matrix are efficacious in improving dielectric performance of composites. The demonstrated approach can also be applied to the design and preparation of other polymers-based nanocomposites filled with ferroelectric particles to achieve desirable dielectric properties.

Fabrication of bulk piezoelectric and dielectric BaTiO3 ceramics using paste extrusion 3D printing technique

“…The obtained maximum ε r is comparable and relatively higher than values by various synthesis methods (eg, sol‐gel, hydrothermal, pechini, mechanochemical, precipitation, and oxalate coprecipitation) reported in Refs . All of dielectric loss measured at 10 3 Hz result in lower than 0.033 as shown in Figure B, which is desired value for application because of low energy loss …”

A facile one step conversion of the sub-micrometer to uniform nanopowder in tetragonal BaTiO3 via a surface active etching salt

“…The dielectric result confirmed that the 77.5 ± 2.5 nm of BaTiO 3 powder product was still in stabilized ferroelectric phase at room temperature, which agrees well with the XRD and DSC results. On the other hand, a lower tan δ of the bulk specimen is required for dielectric device applications because of the low heat produced [51]. According to the dielectric data, the measured dielectric permittivity of the specimen was found to be~53 for 100 Hz, and it decreased slightly to~51 and~50 by increasing the frequency from 1 to 10 kHz.…”

Low‐frequency dielectric performance of polyimide composites containing amorphous polymer‐derived SiCN ceramics

“…High‐dielectric‐constant (high‐ε) polymer‐matrix composites are attractive materials owing to their important applications in the solid‐state energy storage field, (eg, the embedded capacitors) . With the aim to achieve high energy storage densities, a great effort has been made to enhance the dielectric constant (ε) of the composites . There are two types of high‐ε composites, depending on the improvement methodology used.…”