Improved Dielectric Properties and Energy Storage Densities of BaTiO3 Doped PVDF Composites by Heat Treatment and Surface Modification of BaTiO3

The dielectric properties of barium titanate/polyvinylidene fluoride (BT/PVDF) composites are investigated. The doped BT particles are prepared by using simple heat treatment. It is found that 1000 ℃ is the optimal temperature for the doped BT particles to improve the dielectric properties of BT/PVDF composites. Besides, we also find that the breakdown strength of the BT/PVDF composites can be significantly enhanced when the surface of the doped BT particles are pre-modified with phthalic acid or KH550. In particular, the BT/PVDF composites doped with KH550 modified BT particles have the maximum energy storage density of 4.08 J/cm3, which is 81.33 % higher than that of BT/PVDF composites doped with BT particles and without any treatment. Therefore, we can conclude that heat treatment and surface modification of doped BT particles could become new approaches to enhance the energy storage performance of the BT/PVDF composites, which has a good application prospect in the field of dielectric energy storage materials.

Large energy-storage density and positive electrocaloric effect in xBiFeO3–(1 − x)BaTiO3 relaxor ferroelectric ceramics

Large energy storage density and big electrocaloric strength in the BiFeO3–BaTiO3 system.

Enhanced Energy Storage Density and Excellent Thermal Stability Under Low Electric Fields of KF-added BNT–ST-AN Relaxor Ferroelectric Ceramics Prepared by the Solid-state Combustion Technique

Homogeneous 0.722(Bi0.5Na0.5TiO3)-0.228(SrTiO3)-0.05(AgNbO3) (BNT-ST-AN) ceramics with various amounts of potassium fluoride (KF) added were prepared by the solid-state combustion technique. The ceramics presented a single perovskite phase with coexisting rhombohedral (R), cubic (C) and orthorhombic (O) phases. The amount of the R phase decreased while the percentage of the C+O phase increased when KF addition increased from 0.0 to 3.0 mol%. The smallest grain size, the highest density and maximum dielectric constant (em) were achieved with a KF addition of 1.5 mol%. Following this design composition of the ceramics, the highest recoverable energy-storage density (Wrec ~1.60 J/cm3) and η above 85.8% at a low electric field (100 kV/cm) were obtained from BNT-ST-AN with KF addition at 1.5 mol% because this composition contained a morphotropic phase boundary (MPB) region and had the smallest grain size, which gave the lowest remnant polarization (Pr) and a large maximum polarization (Pm). Additionally, BNT-ST-AN with KF addition at 0.15 mol% exhibits stability over a wide range of temperatures (25–150°C) at a low electric field (100 kV/cm), which shows great potential in pulse-power system applications.