Effect of core-shell structured interface on dielectric and energy storage properties of nano Ag decorated BaTiO₃@PDA/P(VDF-HFP) composite films

To improve the interfacial compatibility as well as enhance the dielectric properties of polyvinylidene fluoride (PVDF) based inorganic composite, the BaTiO₃ nanoparticles were coated using Ag decorated inorganic layer polydopamine (PDA). Subsequently the BaTiO₃@PDA-Ag particle was introduced the dielectric polyvinylidene fluoride-hexafluoropropylene (P(VDF-HFP)) matrix and BaTiO₃@PDA-Ag/P(VDF-HFP) composite films were prepared using a solution casting mothed. FTIR and XPS were employed to detect the structures and monographs of the BaTiO₃@PDA-Ag/P(VDF-HFP) composites, and the wide range frequency dielectric spectrometer and ferroelectric property testing system were used to compare the dielectric and polarizing properties of the BaTiO₃@PDA-Ag/P(VDF-HFP) composite films under various electric fields. In the BaTiO₃@PDA-Ag/P(VDF-HFP) composite film with 20wt% BaTiO₃@PDA-Ag particles, a high dielectric constant of 25 and low loss of 0.1, a large electric displacement of 6.2 μC·cm^-2 under 175 M·Vm^-1, and a considerable high discharging energy density of 6.9 J·cm^-3 under 200 M·Vm^-1 are obtained. Considering its favorable interface and considerable electric performances, the core-shell structure of the BaTiO₃@PDA-Ag/P(VDF-HFP) composite provides a reference to the future research of this sorts of composites for energy storage devices.