Frequency dependent conductivity and microwave relaxations in protonic conductors

Colomban, Philippe; Badot, Jean-Claude

doi:10.1016/0167-2738(93)90334-y

Cited by 25 publications

(14 citation statements)

References 12 publications

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“…A molecular dynamic (MD) simulation of CsDSO 4 has been performed to validate the results from neutron powder diffraction. 14 It is worth noting that this proposed model for long-range proton transfer is in good agreement with the experimental data obtained by other methods such as Raman spectroscopy, 15 microwave relaxation 16 and nuclear magnetic resonance spectroscopy (1D NMR, 17 2D NMR 18 ). Hayashi et al reported that the proton transfer between two SO 4 tetrahedra is fast enough, and that the proton transfer is limited in the second stage.…”

Section: Introductionsupporting

confidence: 73%

Nanometer Scale Proton Conductivity and Dynamics of CsHSO₄ and H₃PW₁₂O₄₀ Composites under Non-Humidified Conditions

2010

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We prepared composites of CsHSO4 and H3PW12O40·6H2O (WPA-6H2O), xCsHSO4·(100 − x)WPA-6H2O (mol %) by mechanical milling (MM). The nanometer scale proton dynamics and the non-humidified proton conductivity were investigated using 1H nuclear magnetic resonance (NMR) and alternating current impedance spectroscopies. The non-humidified proton conductivities at 100 °C for pure CsHSO4 and WPA-6H2O were 4.0 × 10−7 and 1.0 × 10−7 S/cm, respectively. On the other hand, the proton conductivity increased significantly to approximately 3 × 10−3 S/cm for the x = 80 and x = 90 composites. Proton conductivity, 1H spin−lattice relaxation time (T 1) and theoretical calculation results suggested the formation of a reacted region with high proton conductivity around the WPA-6H2O cluster after the MM. T 1 measurements for the 90CsHSO4·10WPA-6H2O (mol %) composite revealed that there were two relaxation components, and that the long T 1 and short T 1 components could be correlated to proton motion inside the WPA-6H2O cluster and inside the reacted region, respectively. From an analysis of the short T 1, we found that the proton jumping rate at 100 °C of CsHSO4 increased approximately 1,600 times after mixing CsHSO4 and WPA-6H2O. The proton conductivity of the reacted region was estimated to be 10 × 10−3 S/cm from a theoretical calculation using the effective medium theory.

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Section: Introductionsupporting

confidence: 73%

Nanometer Scale Proton Conductivity and Dynamics of CsHSO₄ and H₃PW₁₂O₄₀ Composites under Non-Humidified Conditions

2010

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“…The AC electrical conductivity analysis imparts detail information about the time‐dependent movements of charge, which leads to conductivity and dielectric relaxation phenomena …”

Section: Resultsmentioning

confidence: 99%

Raman scattering and alternative current conduction mechanism of the high‐temperature phase transition in [(C₄H₉)₄N]₃Bi₂Cl₉

Trigui

Oueslati

Hlel

et al. 2016

J Raman Spectroscopy

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The tri‐tetrabutylammonium nonachlorobibismuthate(III) was found to crystallize in the monoclinic P21/n space group. Two reversible order–disorder phase transitions are observed at 434/430 K and 477/473 K by differential scanning calorimetry technique. The evolution of Raman wavenumber versus temperature shows a remarkable shifting of the bands associated to alkyl chains, suggesting that the phase transition is governed by the reorientational motion of the organic part [(C4H9)4N]+. The analysis of Nyquist plots has revealed the contribution of two electrical active regions corresponding to the bulk mechanism and the distribution of grain boundaries. The AC conductivity is analyzed by different processes: the non‐overlapping small polaron tunneling model proposed as a closely good model for region I and the correlated barrier hopping attributed to the conduction mechanism for region II. Copyright © 2016 John Wiley & Sons, Ltd.

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“…This has been demonstrated for Na β-alumina using sol-gel prepared powders [103,[237][238][239][240] and other ionic conductors [241]. Indeed, there is a strong coupling in the GHz range between the electric field of the microwave and the relaxation of the conducting ions [103,242,243]. Another alternative technique is the coating of hard and anisotropic grains with a gel which will lubricate the grain motion/re-arrangement during the pressing step in the green state and allows fairly good densification [147,148].…”

Section: Tools/requirements For Minimizing the Temperature Of Full Densificationmentioning

confidence: 97%

Chemical Preparation Routes and Lowering the Sintering Temperature of Ceramics

Colomban

2020

Ceramics

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Chemically and thermally stable ceramics are required for many applications. Many characteristics (electrochemical stability, high thermomechanical properties, etc.) directly or indirectly imply the use of refractory materials. Many devices require the association of different materials with variable melting/decomposition temperatures, which requires their co-firing at a common temperature, far from being the most efficient for materials prepared by conventional routes (materials having the stability lowest temperature determines the maximal firing temperature). We review here the different strategies that can be implemented to lower the sintering temperature by means of chemical preparation routes of oxides, (oxy)carbides, and (oxy)nitrides: wet chemical and sol–gel process, metal-organic precursors, control of heterogeneity and composition, transient liquid phase at the grain boundaries, microwave sintering, etc. Examples are chosen from fibers and ceramic matrix composites (CMCs), (opto-)ferroelectric, electrolytes and electrode materials for energy storage and production devices (beta alumina, ferrites, zirconia, ceria, zirconates, phosphates, and Na superionic conductor (NASICON)) which have specific requirements due to multivalent composition and non-stoichiometry.

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Frequency dependent conductivity and microwave relaxations in protonic conductors

Cited by 25 publications

References 12 publications

Nanometer Scale Proton Conductivity and Dynamics of CsHSO₄ and H₃PW₁₂O₄₀ Composites under Non-Humidified Conditions

Nanometer Scale Proton Conductivity and Dynamics of CsHSO₄ and H₃PW₁₂O₄₀ Composites under Non-Humidified Conditions

Raman scattering and alternative current conduction mechanism of the high‐temperature phase transition in [(C₄H₉)₄N]₃Bi₂Cl₉

Chemical Preparation Routes and Lowering the Sintering Temperature of Ceramics

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Frequency dependent conductivity and microwave relaxations in protonic conductors

Cited by 25 publications

References 12 publications

Nanometer Scale Proton Conductivity and Dynamics of CsHSO4 and H3PW12O40 Composites under Non-Humidified Conditions

Nanometer Scale Proton Conductivity and Dynamics of CsHSO4 and H3PW12O40 Composites under Non-Humidified Conditions

Raman scattering and alternative current conduction mechanism of the high‐temperature phase transition in [(C4H9)4N]3Bi2Cl9

Chemical Preparation Routes and Lowering the Sintering Temperature of Ceramics

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Nanometer Scale Proton Conductivity and Dynamics of CsHSO₄ and H₃PW₁₂O₄₀ Composites under Non-Humidified Conditions

Nanometer Scale Proton Conductivity and Dynamics of CsHSO₄ and H₃PW₁₂O₄₀ Composites under Non-Humidified Conditions

Raman scattering and alternative current conduction mechanism of the high‐temperature phase transition in [(C₄H₉)₄N]₃Bi₂Cl₉