Dielectric and Thermal Properties of PEO/PVDF Blend Doped with Different Concentrations of Li4Ti5O12 Nanoparticles

Hafez, R. S.; Hakeem, N. A.; Ward, Azza A.; Ismail, A. M.; El‐Kader, F. H. Abd

doi:10.1007/s10904-020-01637-z

Cited by 29 publications

(15 citation statements)

References 38 publications

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“…At RT, the value of ε ″( ω ) for 1.0 vol% LTO sample at 100 Hz is 1.31 and decreased to 0.245 at 1 MHz but still higher than that of pure PVDF ( ε ″( ω ) = 0.105 at 100 Hz), as shown in Figure 8B(a). The increase of both ε ′( ω ) and ε ″( ω ) with the rise of LTO volume fraction are well supported by DSC measurements as the decrease in the crystallinity of the PNC increases the number of mobile charge carriers 55 . This means that the synthesized PNCs have a high ε ′( ω ) relatively and very small ε ″( ω ), which are desirable characteristics for capacitor applications and can be used in high energy storage capacitors as a dielectric medium 2 …”

Section: Resultsmentioning

confidence: 53%

“…As confirmed before by DSC and SEM, the degree of crystallinity of the PVDF sample decreases and the porosity increases by the addition of LTO NPs. These structural changes and compositional disorder lead to the formation of localized states within the band gap and increase in the number of mobile charge carriers, which are responsible for the ac conduction by hopping mechanism 55 . The dielectric and ac conductivity parameters show their maximum values for the PVDF/1.0 vol% LTO composition as illustrated in Figures 6B, 8B, and 10B.…”

Section: Resultsmentioning

confidence: 93%

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Structural, thermal, and dielectric properties of porous PVDF/Li₄Ti₅O₁₂ nanocomposite membranes for high‐power lithium‐polymer batteries

Nasrallah

El-Metwally

Ismail

2020

Polymers for Advanced Techs

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Polymer nanocomposites consisting of materials such as ionic polymers and nano‐ceramic fillers are widely used in high‐power lithium‐polymer batteries because of their high ionic conductivity, good mechanical strength, electrothermal stability, and better compatibility with electrodes. Nanocomposite films of polyvinylidene fluoride (PVDF)/lithium titanium oxide Li4Ti5O12 (LTO) with different volume fractions of LTO nanoparticles (NPs) are prepared via casting method. The DSC thermograms revealed a slight decrease in the melting temperature Tm and a noticeable reduction in the degree of crystallinity with increasing the volume fraction of LTO. This decrease is confirmed by the increment in the relative fraction of β‐phase in the PVDF matrix calculated from both XRD and FTIR. SEM images indicated the growth of porous globular structures in the presence of LTO NPs. Besides, the hydrophilicity of PVDF is improved by incorporating LTO NPs. The dielectric constant ε′(ω), loss ε″(ω), ac conductivity σac(ω), complex impedance Z*(ω), and Nyquist plots of PVDF/LTO nanocomposites are investigated in the temperature range from 303 to 413 K and frequency range from 100 Hz to 1 MHz. The σac(ω) and frequency exponent s are found to obey the correlated barrier hopping model. Values of the frequency exponent s and the charge carriers binding energy Wm for the studied nanocomposite films decrease with rising temperature and LTO addition. Furthermore, dielectric constant ε′(ω), loss ε″(ω), and ac electrical conductivity σac(ω) of films are found to be strongly frequency and temperature dependent. The localized states density N(EF) at the Fermi level increase with increasing temperature and LTO NPs volume fraction, resulting in the Wm decrease and the enhancement of the ac electrical conductivity σac(ω). The impedance spectrum and Nyquist plots provide an insight into the influence of LTO vol% in the resistive and capacitive characteristics of PVDF/LTO films. These results recommend the choice of LTO NPs as dopants to enhance the electrical properties of the PVDF matrix to be used in high‐power lithium‐ion batteries and electronic devices.

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Section: Resultsmentioning

confidence: 53%

Section: Resultsmentioning

confidence: 93%

Structural, thermal, and dielectric properties of porous PVDF/Li₄Ti₅O₁₂ nanocomposite membranes for high‐power lithium‐polymer batteries

Nasrallah

El-Metwally

Ismail

2020

Polymers for Advanced Techs

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“…In fig.10a& 10b, M ′ approaches 0, confirming the existence of noticeable electrode and/or ionic polarization in the ambient temperature at lower frequencies. A long-tail found at low frequencies is due to the high capacitance related to the electrodes [50]. From fig.10c &10d, the M ′′ spectrum shows an asymmetric spike roughly centered in the region of dispersion.…”

mentioning

confidence: 87%

Impact of polymer blending on ionic conduction mechanism and dielectric properties of sodium based PEO-PVdF solid polymer electrolyte systems

Mallaiah

Jeedi²,

Swarnalatha

et al. 2021

Journal of Physics and Chemistry of Solids

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Solid polymer blend electrolyte systems have been prepared with Poly (ethylene oxide) (PEO), Poly (Vinylidene fluoride) (PVDF) and complexed with Sodium Nitrate (NaNO 3 ) salt by using solution cast technique. The complexion of salt with polymer blend has been confirmed by X-Ray diffraction, Fourier Transmission Infrared Spectroscopy and scanning electron microscopic studies. AC and DC conductivity studies of these polymer blends were carried out by changing the weight percentages of PEO and PVDF with a constant weight percentage of NaNO 3 . The electric modulus (M ' ) and the dielectric properties for all the polymer blend systems have been investigated with impedance spectroscopic analysis as a function of frequency ranging from 100-30MHz. The ionic conductivity of the blend polymer electrolyte systems followed Arrhenius behaviour and the maximum ionic conductivity was observed for PEO:PVdF:NaNO 3 (80:20:5) at room temperature which is attributed to the formation of the amorphous phase.

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“…The value of the dielectric constant is higher at low frequencies, which is because of the orientation of the ions, polar groups and space charge polarization near the electrodes. In contrast, the dielectric constant is lower at high frequencies due to dielectric relaxation [49][50][51][52]. There are no relaxation maxima in both Ɛ ′ and Ɛ ′′ , indicating that the rise in ionic conductivity is primarily because of increased mobile ions.…”

Section: Dielectric Studiesmentioning

confidence: 97%

Effect of TiO2 Nano-filler on Electrical Properties of Na+ Ion Conducting PEO/PVDF Based Blended Polymer Electrolyte

Ganta¹,

Jeedi²,

Kumar

et al. 2021

Preprint

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Nanocomposite Polymer Electrolyte (NCPE) films based on a blend of two polymers poly (ethylene oxide) (PEO) and poly (vinylidene fluoride) (PVDF) complexed with sodium perchlorate (NaClO4) salt and Nano-filler Titanium dioxide (TiO2) (i.e., (80wt%PEO/20wt%PVDF) + 7.5wt%NaClO4+ xwt%TiO2 where x = 3, 6, 9, 12, 15, and 18) were prepared and characterized as potential candidates for battery applications. Electrochemical Impedance Spectroscopy (EIS) has been employed between the frequencies 10 Hz and 4 MHz to investigate electrical, dielectric and electric modulus properties of the prepared NCPE films. Effect of TiO2 Nano-filler concentration on the structural, ionic conductivity, and dielectric relaxation has been studied. The AC conductivity of the NCPE films at high frequencies obeys Jonscher’s power law. The values of DC ionic conductivity calculated by fitting the AC conductivity spectra to the best fit of Joncher’s power law are consistent with the values of DC ionic conductivity calculated from the bulk resistance (Rb) of the NCPE films. The ionic conductivity that depends on temperature follows the Arrhenius rule between the temperatures 298 K and 328 K. The maximum ionic conductivity at ambient temperature 8.75x10-5 S/cm was obtained for (80wt%PEO/20wt%PVDF) +7.5wt%NaClO4 +15wt%TiO2 NCPE film and it is attributed to the decrease in crystallinity. Using Wagner’s polarization technique ionic transport numbers of various NCPE films were measured.

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Dielectric and Thermal Properties of PEO/PVDF Blend Doped with Different Concentrations of Li4Ti5O12 Nanoparticles

Cited by 29 publications

References 38 publications

Structural, thermal, and dielectric properties of porous PVDF/Li₄Ti₅O₁₂ nanocomposite membranes for high‐power lithium‐polymer batteries

Structural, thermal, and dielectric properties of porous PVDF/Li₄Ti₅O₁₂ nanocomposite membranes for high‐power lithium‐polymer batteries

Impact of polymer blending on ionic conduction mechanism and dielectric properties of sodium based PEO-PVdF solid polymer electrolyte systems

Effect of TiO2 Nano-filler on Electrical Properties of Na+ Ion Conducting PEO/PVDF Based Blended Polymer Electrolyte

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Dielectric and Thermal Properties of PEO/PVDF Blend Doped with Different Concentrations of Li4Ti5O12 Nanoparticles

Cited by 29 publications

References 38 publications

Structural, thermal, and dielectric properties of porous PVDF/Li4Ti5O12 nanocomposite membranes for high‐power lithium‐polymer batteries

Structural, thermal, and dielectric properties of porous PVDF/Li4Ti5O12 nanocomposite membranes for high‐power lithium‐polymer batteries

Impact of polymer blending on ionic conduction mechanism and dielectric properties of sodium based PEO-PVdF solid polymer electrolyte systems

Effect of TiO2 Nano-filler on Electrical Properties of Na+ Ion Conducting PEO/PVDF&nbsp;Based Blended Polymer Electrolyte

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Structural, thermal, and dielectric properties of porous PVDF/Li₄Ti₅O₁₂ nanocomposite membranes for high‐power lithium‐polymer batteries

Structural, thermal, and dielectric properties of porous PVDF/Li₄Ti₅O₁₂ nanocomposite membranes for high‐power lithium‐polymer batteries

Effect of TiO2 Nano-filler on Electrical Properties of Na+ Ion Conducting PEO/PVDF Based Blended Polymer Electrolyte