Dielectric properties and energy storage behavior of PVDF-based nanocomposites filled with BaTiO3 nanotubes and nanofibers: A comparative study

Poly vinylidene fluoride (PVDF)-based nanocomposite films comprising varying amounts of surface-modified BaTiO 3 nanotubes (BT NT s ) and nanofibers (BT NF s ) were prepared using tape casting process and subsequent re-melting at 200 °C. The obtained nanocomposite films were studied in terms of microstructure, dielectric properties and energy storage performance. The microstructural investigations showed the relatively uniform dispersion of the BT NT s and BT NF s nanofillers inside the PVDF matrix. At the frequency of 100 Hz, the relative dielectric constant (ɛ r ) of nanocomposites containing 14.3 vol% BT NT s and BT NF s , exhibited significant enhancements of approximately 356 % and 242 %, respectively. The significant reduction in dielectric loss at 1000 Hz, along with the nearly identical values observed, suggested a reduced effectiveness of interfacial polarization at this frequency. The nanocomposites containing BT NT s showed lower dielectric breakdown strength and slightly higher dielectric loss factor in comparison to the nanocomposites filled with BT NF s . A maximum recoverable energy storage density of 4.6 J/cm 3 was achieved for the nanocomposite containing 2.7 vol% BT NT s , which is slightly higher than that observed for nanocomposite with 2.7 vol% BT NF s (4.2 J/cm 3 ). These values correspond to improvements of approximately 53.7 % and 41.2 %, respectively, compared to the pristine PVDF film (2.9 J/cm 3 ).