Experimental studies on the ionic (protonic) transport in ammonium para-tungstate pentahydrate

Chandra, Suresh; Tolpadi, S. K.; Hashmi, S.A.

doi:10.1088/0953-8984/1/46/004

Cited by 17 publications

(7 citation statements)

References 7 publications

(2 reference statements)

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“…and σ vs composition studies: (I) The ion conducting matrix possibly consists of two types of mobile species (H + /H 3 O + and OH -) and the two types of species follow different thresholds and the resultant of the two gives rise to two maxima. The presence of both cations and anions (H + /H 3 O + or OH -) as mobile species has been demonstrated from the coulometric studies for many proton conducting hydrates (Chandra et al 1986(Chandra et al , 1989Hashmi et al 1992). The mobility and interface percolation thresholds for the two mobile species may be different.…”

Section: Resultsmentioning

confidence: 99%

Ion transport in some solid state proton conducting composites studied from volta cell e.m.f. and complex impedance spectroscopy

Lakshmi

Chandra

2002

Bull Mater Sci

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Proton conducting composites of heteropolyacid hydrates (phosphomolybdic acid H 3 PMo 12 O 40 ⋅ ⋅nH 2 O, PMA; phosphotungstic acid H 3 PW 12 O 40 ⋅ ⋅nH 2 O, PTA) and salt hydrate like NiCl 2 ⋅ ⋅6H 2 O were prepared with insulating Al 2 O 3 as dispersoid. The ionic conductivity peaks at two concentrations of Al 2 O 3 indicating two percolation thresholds for proton conduction. Two separate experiments were carried out to check the existence of such percolation thresholds viz. the volta battery experiment involving the measurement of e.m.f. of an electrochemical cell with composites of different compositions used as electrolyte and the composition vs conductivity measured by the complex impedance spectroscopy. The presence of two maxima has been attributed to two different percolation thresholds for the two possible mobile protonic species H + (H 3 O +) and OHarising from the hydrates.

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Section: Resultsmentioning

confidence: 99%

Ion transport in some solid state proton conducting composites studied from volta cell e.m.f. and complex impedance spectroscopy

Lakshmi

Chandra

2002

Bull Mater Sci

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“…Hence, the conductivity reaches the maximum value when a balance between these two opposing forces occurs: increasing the number of charge-carrier ions and decreasing ionic mobility. The type of conducting species responsible for the ionic conductivity in polymer-ammonium salt systems is H + ion [14][15][16][17]. For the present polymer-salt system, the NH 4 + ions of (NH 4 ) 2 SO 4 will be coordinated to the OH groups in PVA.…”

Section: Conductivity Studiesmentioning

confidence: 99%

Impact of ethylene carbonate on electrical properties of PVA/(NH4)2SO4/H2SO4 proton-conductive membrane

Gouda

Badr

Hassan

et al. 2010

Ionics

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A new proton-conductive membrane (PCM) based on poly (vinyl alcohol) and ammonium sulfate (NH 4 ) 2 SO 4 complexed with sulfuric acid and plasticized with ethylene carbonate (EC) at different weight percent were prepared by casting technique. The structural properties of these electrolyte films were examined by XRD studies. The XRD patterns of all the prepared polymer electrolytes reveal the amorphous nature of the films. ac conductivity and dielectric spectra of the electrolyte were studied with changing EC content from weight 0.00 to 0.75 g. A maximum conductivity of 7.3×10 −5 S cm −1 has been achieved at ambient temperature for PCM containing 0.25 g of ethylene carbonate. The electrical conductivity σ, dielectric constant ε′ and dielectric loss ε″ of PCM in frequency range (100 Hz to 100 KHz), and temperature range (300-400 K) were carried out. Measurement of transference number was carried out to investigate the nature of charge transport in these polymer electrolyte films using Wagner's polarization technique. Transport number data showed that the charge transport in these polymer electrolyte systems was predominantly due to ions. The electrolyte with the highest electrical conductivity was used in the fabrication of a solid-state electrochemical cell with the configuration (Mg/PCM/PbO 2 ). Various cell parameters ldensity, and current density were determined. The fabricated cells gave capacity of 650 μAh and have an internal resistance of 11.6 kΩ.

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“…3 However, NH 4 + has been identified as a mobile ion in other systems, such as in the ammonium paratungstate pentahydrate system. 4 The proton conductivity of many types of electrolytes (including APP-based) is strongly dependent on relative humidity. 1 Metal borohydrides and metal boranes have recently been identified as extremely promising ion conductors for solid-state battery applications.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Pure APP has a low conductivity of 10 –7 S/cm at 250 °C, found to be dominantly electronic, thus indicating that NH 4 + is not responsible for the conductivity as a mobile cation . However, NH 4 + has been identified as a mobile ion in other systems, such as in the ammonium para -tungstate pentahydrate system . The proton conductivity of many types of electrolytes (including APP-based) is strongly dependent on relative humidity …”

Section: Introductionmentioning

confidence: 99%

Reorientational Motions and Ionic Conductivity in (NH₄)₂B₁₀H₁₀ and (NH₄)₂B₁₂H₁₂

et al. 2018

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We investigated molecular dynamics in two ammonium borane systems from the group of promising ion conductors. The investigation was performed by means of 1 H and 11 B NMR spectroscopy and spin−lattice relaxation techniques. We identified two reorientational processes, the rotations of NH 4 units that are present already at low temperatures and rotations of large boron cages, B 10 H 10 or B 12 H 12 , which are thermally activated and become prominent above 250 K. Activation energies for these processes were determined. In addition, solid-state ion conductivity measurements were conducted to determine poor NH 4 + conductivity of both systems.

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Experimental studies on the ionic (protonic) transport in ammonium para-tungstate pentahydrate

Cited by 17 publications

References 7 publications

Ion transport in some solid state proton conducting composites studied from volta cell e.m.f. and complex impedance spectroscopy

Ion transport in some solid state proton conducting composites studied from volta cell e.m.f. and complex impedance spectroscopy

Impact of ethylene carbonate on electrical properties of PVA/(NH4)2SO4/H2SO4 proton-conductive membrane

Reorientational Motions and Ionic Conductivity in (NH₄)₂B₁₀H₁₀ and (NH₄)₂B₁₂H₁₂

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Experimental studies on the ionic (protonic) transport in ammonium para-tungstate pentahydrate

Cited by 17 publications

References 7 publications

Ion transport in some solid state proton conducting composites studied from volta cell e.m.f. and complex impedance spectroscopy

Ion transport in some solid state proton conducting composites studied from volta cell e.m.f. and complex impedance spectroscopy

Impact of ethylene carbonate on electrical properties of PVA/(NH4)2SO4/H2SO4 proton-conductive membrane

Reorientational Motions and Ionic Conductivity in (NH4)2B10H10 and (NH4)2B12H12

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Reorientational Motions and Ionic Conductivity in (NH₄)₂B₁₀H₁₀ and (NH₄)₂B₁₂H₁₂