Effect of hot pressing temperature on dielectric and energy storage properties of Ba_0.6Sr_0.4TiO₃/poly(vinylidene fluoride) composites

0-3 Ba_0.6Sr_0.4TiO₃ (BST)/poly(vinylidene fluoride) (PVDF) composites were prepared via tape casting and then followed by hot pressing (HP) method. The effect of HP temperature on the microstructure, dielectric properties and energy storage density of the composites were investigated. With the increase of HP temperatures, the dielectric constant increases, whereas the dielectric loss decreases first and then increases. The energy storage density increases first and then decreases. And the composites exhibit a high dielectric tunability (> 85.6 %) and flexibility. Furthermore, the composites display optimal dielectric properties when the HP temperature is 120 °C, the values of dielectric constant and loss are 42.19 and 0.034, respectively. Particularly, compared with the composites formed under HP at room temperature (RT) (1.23 J/cm³) and the pure PVDF matrix (2.8 J/cm³). The values of energy storage density of composites with HP at 120 °C (4.1 J/cm³) has been improved 3.33 times and 1.47 times, respectively. The composites with tunable microstructure and dielectric properties show good potential in supercapacitor and energy storage devices.