Zirconia doped barium titanate induced electroactive β polymorph in PVDF-HFP: high energy density and dielectric properties

Abstract

Zirconium-doped barium titanate (BZT-08, Ba(Ti_0.92 Zr_0.08)O₃) particles were synthesized and PVDF-HFP-based composites were prepared by melt mixing to design materials with tunable dielectric and ferroelectric properties. Composites of PVDF-HFP and barium titanate (BT) particles were also prepared to realize the exceptional properties associated with the BZT-08-like stabilization of two ferroelectric phases, i.e. tetragonal and orthorhombic at room temperature. To facilitate the uniform dispersion and interfacial adhesion with the matrix, the particles were modified with (3-aminopropyl) triethoxysilane. The dependence of the dielectric and ferroelectric properties of the as-prepared composites were systematically investigated in this study with respect to a wide range of frequencies. The composites with BZT-08 exhibited the significantly high dielectric permittivity of ca. 26 (at 100 Hz) and a high energy density (2.7 J cm⁻³ measured on 100 μm thick film) at room temperature with respect to the control PVDF-HFP and PVDF-HFP/BT composites. Interestingly, the BZT-08 particles facilitated the electroactive β polymorph in the PVDF-HFP and enhanced polarization in the composites, leading to improved ferroelectric properties in the composites.