Amplified Dielectric Properties of PVDF-HFP/SrTiO3 Nanocomposites for a Flexible Film Capacitor.

Abstract

A simple solution casting technique was used to fabricate perovskite strontium titanate (SrTiO3)-loaded poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) nanocomposite films for efficient energy storage applications. Various microscopic and spectroscopic methods were used to study the characteristics of the polymer nanocomposite films, like Fourier transform infrared spectroscopy (FTIR), X-ray diffraction technique (XRD), field emission scanning electron microscopy (FESEM), ultraviolet-visible spectroscopy, thermogravimetric analysis, and mechanical tensile test (stress vs strain). The FTIR, XRD, and FESEM analyses confirmed the incorporation and proper dispersion of SrTiO3 nanoparticles in the PVDF-HFP polymer matrix. An improvement in the optical, thermal, and mechanical behavior of the nanocomposite film was observed compared to the pure polymer. The values of dielectric constant, loss tangent, and AC conductivity of pure PVDF-HFP polymer and PVDF-HFP/SrTiO3 nanocomposites (2, 6, and 10 wt % SrTiO3 loadings) were analyzed in a temperature and frequency span of 30-150 °C and 1-100 kHz, respectively. To better understand the electrical properties of the materials, Nyquist plots were generated, and their related circuit designs were fitted. The 2 wt % SrTiO3 loaded nanocomposite exhibited the highest dielectric enhancement and AC conductivity compared to higher filler-loaded nanocomposites. This exceptional dielectric enhancement at very small filler loading is beneficial for commercialization and economically viable for real-time applications.