Complex impedance, dielectric properties and electrical conduction mechanism of La0.5Ba0.5FeO3−δ perovskite oxides

Nasri, S.; Hafsia, A. L. Ben; Tabellout, M.; Megdiche, M.

doi:10.1039/c6ra10589k

Cited by 63 publications

(19 citation statements)

References 32 publications

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“…The unit cell parameter of the LB phase is constant 3.907(1) Å and does not depend on the overall composition. It is larger than the lattice parameter for pure La 0.5 Ba 0.5 CoO 3−δ (3.893 Å [11]), similar to La 0.5 Ba 0.5 MnO 3 (3.9077 Å [31]), and smaller than La 0.5 Ba 0.5 FeO 3−δ (3.9384 Å [32]). The unit cell parameter of the BZ phase increases from 4.162(1) to 4.183(2) Å with increasing Y content.…”

Section: Synthesismentioning

confidence: 93%

High-Performance La0.5Ba0.5Co1/3Mn1/3Fe1/3O3−δ-BaZr1−zYzO3−δ Cathode Composites via an Exsolution Mechanism for Protonic Ceramic Fuel Cells

et al. 2018

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A novel exsolution process was used to fabricate complex all-oxide nanocomposite cathodes for Protonic Ceramic Fuel Cells (PCFCs).The nanocomposite cathodes with La 0.5 Ba 0.−δ nominal composition were prepared from a single-phase precursor via an oxidation-driven exsolution mechanism. The exsolution process results in a highly nanostructured and intimately interconnected percolating network of the two final phases, one proton conducting (BaZr 1−z Y z O 3−δ ) and one mixed oxygen ion and electron conducting (La 0.5 Ba 0.5 Co 1/3 Mn 1/3 Fe 1/3 O 3−δ ), yielding excellent cathode performance. The cathode powder is synthesized as a single-phase cubic precursor by a modified Pechini route followed by annealing at 700 • C in N 2 . The precursor phase is exsolved into two cubic perovskite phases by further heat treatment in air. The phase composition and chemical composition of the two phases were confirmed by Rietveld refinement. The electrical conductivity of the composites was measured and the electrochemical performance was determined by impedance spectroscopy of symmetrical cells using BaZr 0.9 Y 0.1 O 2.95 as electrolyte. Our results establish the potential of this exsolution method where a large number of different cations can be used to design composite cathodes. The La 0.5 Ba 0.5 Co 1/3 Mn 1/3 Fe 1/3 O 3−δ -BaZr 0.9 Y 0.1 O 2.95 composite cathode shows the best performance of 0.44 Ω·cm 2 at 600 • C in 3% moist synthetic air.

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Section: Synthesismentioning

confidence: 93%

High-Performance La0.5Ba0.5Co1/3Mn1/3Fe1/3O3−δ-BaZr1−zYzO3−δ Cathode Composites via an Exsolution Mechanism for Protonic Ceramic Fuel Cells

et al. 2018

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“…Where is the angular frequency, ε o is the dielectric permittivity of the free space and ε " represents the dielectric loss. = 2 ℎ = ℎ (11 ) and are the ac and dc conductivities, A and n are the frequency independent Arrhenius constant and the power law exponent with value 0 < < 1. ω h is hopping frequency, and at this particular frequency, ac conductivity becomes double of dc conductivity [69][70][71]. Although, JPL provides sufficient information about the hopping mechanism, it agrees sound only at higher frequencies and fails at lower frequencies due to electrode polarization effect.…”

Section: The Real Part Of Complex Conductivitymentioning

confidence: 99%

Effect of salt concentration on dielectric properties of Li-ion conducting blend polymer electrolytes

Arya

Sharma

2018

J Mater Sci: Mater Electron

154

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In the present article, we have studied the effect of the salt concentration (LiPF 6 ) on transport properties and ion dynamics of blend solid polymer electrolyte (PEO-PAN) prepared by solution cast technique. Fourier transform infrared (FTIR) spectroscopy confirms the presence of microscopic interactions such as polymer-ion and ion-ion interaction evidenced by a change in peak area of anion stretching mode. The fraction of free anions and ion pairs obtained from the analysis of FTIR implies that both influence the ionic conductivity with different salt concentration.The complex dielectric permittivity, dielectric loss, complex conductivity have been analyzed and fitted in the entire frequency range (1 Hz-1 MHz) at room temperature. The addition of salt augments the dielectric constant and shift of relaxation peak in loss tangent plot toward high frequency indicates a decrease of relaxation time. We have implemented the Sigma representation (σ'' vs. σ') for solid lithium ion conducting films which provide better insight toward understating of the dispersion region in Cole-Cole plot (ε'' vs. ε') in lower frequency window. The dielectric strength, relaxation time and hopping frequency are in correlation with the conductivity which reveals the authenticity of results. Finally, the ion transport mechanism was proposed for getting the better understanding of the ion migration in the polymer matrix.

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“…ω h is hopping frequency and at this particular frequency ac conductivity becomes double of dc conductivity. For some polymers n may be greater than unity also [68][69][70].…”

Section: Ac Conductivity Analysismentioning

confidence: 99%

Structural, electrical properties and dielectric relaxations in Na⁺-ion-conducting solid polymer electrolyte

Arya¹,

Sharma²

2018

J. Phys.: Condens. Matter

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In this paper, we have studied the structural, microstructural, electrical, dielectric properties and ion dynamics of a sodium-ion-conducting solid polymer electrolyte film comprising PEO-NaPF+ x wt. % succinonitrile. The structural and surface morphology properties have been investigated, respectively using x-ray diffraction and field emission scanning electron microscopy. The complex formation was examined using Fourier transform infrared spectroscopy, and the fraction of free anions/ion pairs obtained via deconvolution. The complex dielectric permittivity and loss tangent has been analyzed across the whole frequency window, and enables us to estimate the DC conductivity, dielectric strength, double layer capacitance and relaxation time. The presence of relaxing dipoles was determined by the addition of succinonitrile (wt./wt.) and the peak shift towards high frequency indicates the decrease of relaxation time. Further, relations among various relaxation times ([Formula: see text]) have been elucidated. The complex conductivity has been examined across the whole frequency window; it obeys the Universal Power Law, and displays strong dependency on succinonitrile content. The sigma representation ([Formula: see text]) was introduced in order to explore the ion dynamics by highlighting the dispersion region in the Cole-Cole plot ([Formula: see text]) in the lower frequency window; increase in the semicircle radius indicates a decrease of relaxation time. This observation is accompanied by enhancement in ionic conductivity and faster ion transport. A convincing, logical scheme to justify the experimental data has been proposed.

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Complex impedance, dielectric properties and electrical conduction mechanism of La_0.5Ba_0.5FeO_3−δ perovskite oxides

Abstract: The new perovskite compound La0.5Ba0.5FeO3−δ was prepared by the sol–gel method.

Cited by 63 publications

References 32 publications

High-Performance La0.5Ba0.5Co1/3Mn1/3Fe1/3O3−δ-BaZr1−zYzO3−δ Cathode Composites via an Exsolution Mechanism for Protonic Ceramic Fuel Cells

High-Performance La0.5Ba0.5Co1/3Mn1/3Fe1/3O3−δ-BaZr1−zYzO3−δ Cathode Composites via an Exsolution Mechanism for Protonic Ceramic Fuel Cells

Effect of salt concentration on dielectric properties of Li-ion conducting blend polymer electrolytes

Structural, electrical properties and dielectric relaxations in Na⁺-ion-conducting solid polymer electrolyte

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Complex impedance, dielectric properties and electrical conduction mechanism of La0.5Ba0.5FeO3−δ perovskite oxides

Abstract: The new perovskite compound La0.5Ba0.5FeO3−δ was prepared by the sol–gel method.

Cited by 63 publications

References 32 publications

High-Performance La0.5Ba0.5Co1/3Mn1/3Fe1/3O3−δ-BaZr1−zYzO3−δ Cathode Composites via an Exsolution Mechanism for Protonic Ceramic Fuel Cells

High-Performance La0.5Ba0.5Co1/3Mn1/3Fe1/3O3−δ-BaZr1−zYzO3−δ Cathode Composites via an Exsolution Mechanism for Protonic Ceramic Fuel Cells

Effect of salt concentration on dielectric properties of Li-ion conducting blend polymer electrolytes

Structural, electrical properties and dielectric relaxations in Na+-ion-conducting solid polymer electrolyte

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Complex impedance, dielectric properties and electrical conduction mechanism of La_0.5Ba_0.5FeO_3−δ perovskite oxides

Structural, electrical properties and dielectric relaxations in Na⁺-ion-conducting solid polymer electrolyte