Enhancement of cation mobility in some sulphate phases due to a paddle-wheel mechanism

Lundén, Arnold

doi:10.1016/s0167-2738(88)80026-2

Cited by 67 publications

(32 citation statements)

References 34 publications

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“…Similar cation-anion coupling has been observed in other high-temperature sulfate phases that exhibit fast ion conduction, such as LiNaSO 4 and LiAgSO 4 46 , and in the high-temperature modification of sodium ortho-phosphate, Na 3 PO 4 47,48 . In the opposite sense, limited rotational motion of SO 4 2− anions in Na 2 SO 4 at elevated temperatures has been correlated with low Na-ion conductivity 45 .…”

supporting

confidence: 71%

“…It is therefore reasonable to hypothesize that the paddlewheel effect could be exploited to design new SEs with high ionic conductivity 59,60 . Unfortunately, exploiting these rotational degrees of freedom can present a challenge, as the paddlewheel mechanism is typically observed in high-temperature polymorphs having expanded volumes [39][40][41][42][43][45][46][47][48][49][50][51][52][53][54]61 . These polymorphs can be difficult to stabilize at ambient temperatures, as is desired for the operation of a battery 51,62 .…”

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confidence: 99%

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Low-temperature paddlewheel effect in glassy solid electrolytes

2020

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Glasses are promising electrolytes for use in solid-state batteries. Nevertheless, due to their amorphous structure, the mechanisms that underlie their ionic conductivity remain poorly understood. Here, ab initio molecular dynamics is used to characterize migration processes in the prototype glass, 75Li 2 S-25P 2 S 5 . Lithium migration occurs via a mechanism that combines concerted motion of lithium ions with large, quasi-permanent reorientations of PS 4 3− anions. This latter effect, known as the 'paddlewheel' mechanism, is typically observed in hightemperature crystalline polymorphs. In contrast to the behavior of crystalline materials, in the glass paddlewheel dynamics contribute to Lithium-ion mobility at room temperature. Paddlewheel contributions are confirmed by characterizing spatial, temporal, vibrational, and energetic correlations with Lithium motion. Furthermore, the dynamics in the glass differ from those in the stable crystalline analogue, γ-Li 3 PS 4 , where anion reorientations are negligible and ion mobility is reduced. These data imply that glasses containing complex anions, and in which covalent network formation is minimized, may exhibit paddlewheel dynamics at low temperature. Consequently, these systems may be fertile ground in the search for new solid electrolytes.

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confidence: 71%

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confidence: 99%

Low-temperature paddlewheel effect in glassy solid electrolytes

2020

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“…Some authors try to explain the high temperature conductivity with a percolation‐type mechanism . Other authors claim that the paddle‐wheel mechanism within so called rotator phases is responsible for the increased ion conductivity in certain high temperature ion conductors, for example, for CsH 2 PO 4 . Moreover, big molecular rotors are used as mechanical elements for molecular machines …”

Section: Figurementioning

confidence: 99%

“…[13,14] For the conduction mechanism of high-temperature ionic conductors, two different mechanisms are discussed in literature. [17][18][19] Moreover,b ig molecular rotorsa re used as mechanical elements for molecular machines. [15,16] Other authors claim that the paddle-wheel mechanism within so called rotator phasesi sr esponsible for the increasedi on conductivity in certain high temperature ion conductors,f or example, for CsH 2 PO 4 .…”

mentioning

confidence: 99%

“…[15,16] Other authors claim that the paddle-wheel mechanism within so called rotator phasesi sr esponsible for the increasedi on conductivity in certain high temperature ion conductors,f or example, for CsH 2 PO 4 . [17][18][19] Moreover,b ig molecular rotorsa re used as mechanical elements for molecular machines. [20][21][22] In this article, we investigate the phase transition of b-bistetramethylammonium hydrogencyclotriphosphate to ap hase, which features molecular dynamics at elevated temperatures by meansofdifferential scanning calorimetry (DSC),impedance spectroscopy,v ariable temperature powder X-ray diffraction, and variable temperature solid state nuclear magnetic resonance( NMR).…”

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Investigation of Bistetramethylammonium Hydrogencyclotriphosphate—A Molecular Rotor?

Mangstl

Weber

Jardón-Álvarez

et al. 2018

Chemistry A European J

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The crystalline phase β-[N(CH ) ] HP O undergoes a reversible phase transition to γ-[N(CH ) ] HP O , which was studied by dynamic scanning calorimetry and X-ray diffraction. The rotational dynamics of the anion [P O ] were evident from variable temperature P magic angle spinning (MAS) NMR spectroscopy. The rotational dynamics could be simulated with a 3-site jump model, which yields spectra in good agreement with experiment. An activation energy of 0.6 eV could be estimated from line shape analysis. Impedance spectra reflect a bulk proton conductivity of γ-[N(CH ) ] HP O of 6.9×10 S cm at 240 °C and an activation energy of approximately 1.0 eV. Thus this salt features bulk protonic motion, while local rotational anionic motion happens with activation energies of the same order, as suggested by the paddle-wheel mechanism.

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Conducting Solids: In the Search for Multivalent Cation Transport

Хартон¹

2009

Solid State Electrochemistry I

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The interfacial and transport phenomena related to multivalent cation migration in solids are of major interest in our understanding of many fundamental mechanisms and for numerous potential applications. The exact identification and quantitative analysis of these phenomena are, however, among the most complex tasks in solidstate electrochemistry. In those systems which comprise several types of ion that may be mobile, a precise separation of the contributions provided by different ionic species is only possible by combining several complementary electrochemical, spectroscopic, and microscopic techniques. These experiments require also careful examination of their reproducibility, an assessment of the relative roles of all factors that influence ionic transport, a thorough characterization of the materials, the elimination of various parasitic effects, and the correct accounting of possible parallel and alternative mechanisms. For multivalent cation conductors, typical experimental problems include the presence of minor amounts of impurities (e.g., protons or alkaline metal cations), interfacial transport (via extended defects, grain boundaries or surfaces), electronic conduction and/or phase decomposition processes induced by the applied electrical field, cation demixing under chemical potential gradients, possible volatilization of components, phase separation at the interfaces, and other complex electrode phenomena. In particular, due to the electrostatic and stereological factors discussed in previous chapters, the mobility of multivalent cations is always lower compared to that of monovalent species. Consequently, even microscopic amounts of ionic impurities, barely distinguishable by standard analytical methods, may have non-negligible effects on the transport properties. In the case of electrochemical measurements involving direct currents, high electrical and polarization resistances may lead to excessively high voltages, the generation of electronic charge carriers, and/or decomposition. These factors are in part responsible for the contradictory conclusions, various different opinions, doubts and questions reported with regards to migration-and intercalation-related phenomena when the cation Solid State Electrochemistry I: Fundamentals, Materials and their Applications. Edited by Vladislav V. Kharton

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Enhancement of cation mobility in some sulphate phases due to a paddle-wheel mechanism

Cited by 67 publications

References 34 publications

Low-temperature paddlewheel effect in glassy solid electrolytes

Low-temperature paddlewheel effect in glassy solid electrolytes

Investigation of Bistetramethylammonium Hydrogencyclotriphosphate—A Molecular Rotor?

Conducting Solids: In the Search for Multivalent Cation Transport

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