Dielectric Switching and Ferroelectric Studies of α, γ PVDF Phases for Energy Storage Properties

This article presents the current–voltage (I–V) characteristics, ferroelectric (P–E) and energy density properties of polyvinylidene fluoride (PVDF) film samples synthesized by melt-press and solution-cast techniques. Our earlier work reported the α and γ -PVDF phase stabilization in PVDF film samples processed by melt-pressing and solution-casting respectively. In the present work, the I–V loops of pure PVDF film samples were recorded with variable delay time from 0.0005 to 1 s in order to understand the switching behavior response of molecular dipoles in different PVDF molecular conformations. The hysteresis behavior of I–V loops revealed the dominance of dipolar switching current in both the α and γ-PVDF phases. The slim P–E hysteresis loops with low remnant polarization Pr values ≈0.26 and 0.21 μC/cm2 at an applied electric field of 100 kV/cm for α and γ -PVDF phases respectively were traced. The dielectric energy storage efficiency η as calculated from P–E loop data was found to be ≈37.7% and 38.6%, respectively, for α and γ -phases of PVDF. The low leakage current and slim P–E hysteresis behavior in both the α and γ -phases of PVDF are favorable or desired for their application in dielectric energy storage capacitors.