BaTiO3-assisted rGO-based flexible thin films for energy storage applications

Flexible dielectric materials are widely explored and used for energy storage applications. In this paper, we present a research work on the development of new flexible dielectric films by combining poly(vinyl alcohol) (PVA) used as flexible polymer matrix and reduced grapheme oxide (rGO) and barium titanate (BaT) added in different ratios to tailor their capacitance. The properties of resultant nanocomposite films have been tailored based on the properties of their constituents; flexibility of the PVA, high thermal stability better dielectric properties due to both fillers i.e., rGO and BaT. The synthesized nanocomposite films prepared by different ratio of these three components were characterized for their structural, chemical, morphological, thermal, and dielectric properties. Their dielectric studies carried using impedance analyzer at room temperature revealed that nanocomposite with rGO:barium titanate:poly(vinyl alcohol) = 0.3:2.5:10 shows excellent real part of permittivity of 66 at 20 Hz which decreased to 10.9 at very high frequency of 2 MHz and low energy loss of 0.8 at 20 Hz which was reduced to 0.06 at 2 MHz. Also energy storage capacity of nanocomposites was calculated, and it was found that rGO:barium titanate:poly(vinyl alcohol) = 0.3:1:10 showed best energy storing properties with total energy density, recoverable energy density, and energy loss of 2.1 × 10⁻⁴ kJ/m³, 1.5 × 10⁻⁴ kJ/m³, and 5.2 × 10⁻⁵ kJ/m³. Its efficiency was 71%. The presented synthesized flexible dielectric films with tailorable dielectric performances are very desirable for flexible capacitor sensing application due to their excellent flexibility, efficient thermal, and dielectric properties.