The effects of double-shell organic interfaces on the dielectric and energy storage properties of the P(VDF-CTFE)/BT@HBP@PDA-Ag nanocomposite films

Abstract

In order to improve the interfacial compatibility of PVDF-based nanocomposites, the BaTiO3 (BT) nanoparticles are coated successively using double-shell layers of hyperbranched polyamide polyamide (HBP) and polydopamine (PDA). Subsequently, the BT particles with an organic double-shell structure is compound to a dielectric poly (vinylidene fluoride-chlorotrifluoroethylene) (P(VDF-CTFE)), and the flexible 0–3P(VDF-CTFE)/BT@HBP@PDA-Ag nanocomposites films with ∼20 μm in thickness are obtained using spin-casting method. The results of FTIR, TEM and SEM indicate that the good interfacial compatibility of the composites favors the dispersion of coated BT particles in the P(VDF-CTFE) matrix. Consequently, the P(VDF-CTFE)/BT@HBP@PDA-Ag nanocomposites film shows a large dielectric permittivity (εr ∼ 40) with depressed dielectric loss tangent at a low frequency of 0.1 Hz. In addition, a high electrical displacement of 5.6 μC/cm2 and a large discharged energy density of 7.0 J/cm3 are obtained in this nanocomposite film due to the together contributions of ionic polarization of BT and the penetration effect of electrons. Considering its relative low dielectric loss, the double-shell coating on the inorganic particles in the polymer/ceramic composite film provides an effective way of interfacial fabricating for the high dielectric and energy storage performance. Keywords: P(VDF-CTFE), BaTiO3, One-core-double-shell, Dielectric, Energy storage