Polarization and space charge performance in PVDF with MPB composition BCZT doped composite films

Abstract

The morphotropic phase boundary composition 47(Ba 0.7 Ca 0.3 )TiO 3 -0.53Ba(Zr 0.2 Ti 0.8 )O 3 (calcium barium zirconate titanate, BCZT) were doped in poly(vinylidene fluoride) matrix by solution casting method. The effect of BCZT particles on polarization characteristics of composite films were investigated through dielectric spectra, hysteresis, and thermally stimulated discharge current measurements. It reveals that relative dielectric constant, remnant polarization, and energy storage density gradually increase and reach the maximum value with 39 at 100 Hz, 1.17 lC/cm 2 , and 3.69 J/cm 3 at the concentration of 20 vol % BCZT. The Gaussian method was employed to decompose thermally stimulated discharge current composite peaks and an approximate model was used to analyze the activation energy levels of these films. The results indicated that the introduction of BCZT is effective for the charge carrier traps and activation energy distribution in the relaxation process of composite films. The decreased molecular movements, and increased interfaces formed between the BCZT grains and the poly(vinylidene fluoride) matrix may be responsible for these performances. And a new relaxation peak appeared at about 370 K in composites when BCZT concentration exceeded 20 vol %, which was considered to be caused by the ferroelectric-paraelectric phase transition of BCZT.

Modulation in polymer properties in PVDF/BCZT composites with ceramic content and their energy density capabilities

“…A medium diffraction peak around 36.23 was a β-PVDF peak. [7,14,15] The results confirmed the formation of γ-phase with traces of β-phase in a pure PVDF film sample. In the XRD pattern of PVDF/ BCZT composite film with 50 wt% BCZT content displayed all the peaks corresponding to the pure BCZT phase.…”

“…Finally, the dried film on the glass substrate has been peeled off and used for further analysis and testing as it is. [7,32,35] The thickness of pure PVDF and PVDF/BCZT composite films were measured and found to in the range 0.1 to 0.3 mm.…”

“…The dielectric permittivity of any medium depends on its electroactive content and could be related to the degree of polarization which includes all polarizations (electronic, ionic, orientational, and interfacial). [7,28,32] In PVDF/BCZT composite film, the resultant dielectric permittivity is due to (a) electroactive phase fraction of PVDF, (b) ferroelectric BCZT ceramic and, (c) interfacial interactions between the PVDF phases and BCZT ceramic particles. The value of relative permittivity (ε r ) for composite films increased with an increase in ceramic BCZT content in it ( Figure 4A).…”

“…[4][5][6] Hence, PVDF-based material forms are always attractive for applications in flexible energy storage devices. [7][8][9][10][11] The PVDF is a semi-crystalline polymer which can be stabilized in its different polymorphs α, β, γ, δ, and ε. Among all, β and γ-phases of PVDF show good ferro/piezoelectric properties.…”

“…[28,29] The significantly enhanced dielectric constant and energy storage density has been found in PVDF-BCZT composites which makes them the most suitable candidate for applications in energy storage devices. [7][8][9][10][11]30] In the present work, PVDF-BCZT composite films with different wt% of BCZT content has been fabricated by the solution-cast technique. The FTIR, XRD, dielectric, and ferroelectric studies explored the phase stabilization and, dielectric properties and energy storage capabilities of PVDF/BCZT composite films.…”