High dielectric constant and low dielectric loss of Y/Mn co-doped BST@ZrO2/PVDF composite films for wearable capacitor applications

In order to develop infinite capacitive materials with high dielectric constant and low dielectric loss, influences of Y/Mn co-doping and ZrO2 coating on the dielectric properties of barium strontium tinanate/polyvinylidene fluoride (BST/PVDF) composite films were systematically investigated with fixing Y concentration as 0.3 at.% and varying Mn concentration from 1 at.% to 4 at.%. The experimental results show that the dielectric constant of BST@ZrO2/PVDF composite increases by 50% relative to BST/PVDF and the dielectric loss is evidently depressed. In comparison with BST@ZrO2/PVDF sample, furthermore, the dielectric constant of Y/Mn co-doped BST@ZrO2/PVDF samples increases by about 60% and the dielectric loss further reduces at 1 kHz. The promoted dielectric performances of composite originate from the space charge separation formed by Y/Mn co-doping and the limitation of electronic mobility by coated ZrO2. Y/Mn co-doped BST@ZrO2/PVDF composite film with 3% Mn has a dielectric constant of 37.9, a dielectric loss of 0.0117, superior dielectric temperature stability (3.1% from -5 degrees C to 45 degrees C at 1 kHz), and a discharged energy density of 5.67 J/cm(3) at 600 kV/cm. The simultaneous optimization of dielectric constant and dielectric loss of BST/PVDF composite is realized in this experiment. The superior dielectric temperature stability suggests the application potential of Y/Mn co-doped BST@ZrO2/PVDF as wearable capacitors.