Effect of AgNbO3 Morphology on Dielectric and Energy Storage Properties of Polyvinylidene Fluoride-Based Nanocomposites

Introducing high dielectric constant ceramics into polymers can improve the dielectric constant and energy storage performance of composites without reducing the breakdown resistance of polymers. The remnant polarization of the antiferroelectric material is very small, and it has a high saturation polarization, which is beneficial to improving the energy storage density. In this study, three different microstructures of AgNbO₃ particles, C-AN, S-AN, and H-AN, were prepared by the co-precipitation method, traditional solid phase method, and hydrothermal method, respectively. Among them, C-NPS is a nanometer powder and S-AN and H-AN are micron powders. The surface of the particles was modified with silane coupling agent KH560 to improve the compatibility of the inorganic–organic interface. Composite materials were prepared by the casting method. The results show that the C-AN nanoparticle has a large specific surface area, small particle size, and uniform size distribution and its dispersion in the PVDF (polyvinylidene fluoride) matrix is the best. The high saturation polarization of the antiferroelectric AgNbO₃ filler under a high electric field can induce the composite to produce a high P_max (maximum polarization) value and reduce P_r (remanent polarization), thereby ultimately increasing the energy storage density of the nanocomposite. The energy storage density of the 0.3 wt % C-AN/PVDF composite is 6.03 J/cm³ under the electric field of 300 kV/mm.