Optimized Dielectric and Ferroelectric Properties of P(VDF-HFP)/Co₃O₄ Nanocomposites for Flexible Thin Film Capacitor Applications

Poly (vinylidene fluoride) (PVDF) and its copolymers are widely familiar for their exceptional electroactive characteristics, including dielectric constant, piezoelectricity, and ferroelectricity, making them ideal for use in energy transfer applications, generation, and storage, as well as for use in sensors, actuators, and capacitors. This study focused on the synthesis of P(VDF-HFP)/Co<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> polymer nanocomposite films, incorporating 2D Co<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> nano mesh as fillers in the matrix of polymer. The structural, morphological, dielectric, ferroelectric, and thermal characteristics of these composites were thoroughly investigated. High-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) confirmed that the Co<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> particles exhibit a rectangular shape, and SEM further demonstrated a homogeneous distribution of Co<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> within the polymer matrix, which significantly influenced the composite's properties. The DTG analysis indicated the shift in maximum degradation temperature, resulting in enhanced thermal stability and reduced residual mass due to catalytic effect on polymer decomposition. Dielectric studies revealed a considerable enhancement in dielectric constant from 8.96 for pure P(VDFHFP) to 22.02 for the 7.0 wt. % Co<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> composite, along with a reduction in dielectric losses because of interfacial polarization and enhanced dipole mobility. The Cole-Cole plots confirmed nonDebye relaxation behavior, showing that higher Co<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> concentrations resulted in an increase in relaxation peak frequencies and shorter relaxation times. Weibull analysis reveals the moderate Co<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> concentration enhances breakdown strength and stability. The ferroelectric properties demonstrated a maximum saturated polarization of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2.04 \mu \mathrm{C} / \text{cm}^{2}$</tex> at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.4 \text{wt}. \%$</tex>. These findings suggest that P(VDF-HFP)/Co<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> nanocomposites have significant potential for advanced dielectric applications, thin film capacitors, and energy storage systems.