Broadband Conductivity Spectroscopy for Studying the Dynamics of Mobile Ions in Materials with Disordered Structures

Funke, K.

doi:10.1002/9783527636839.ch6

Cited by 4 publications

(2 citation statements)

References 69 publications

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“…Rather, this could find its origin in the increased entropy of the material, which has a fundamental effect on the ion dynamics. From a certain level of disorder, migration involves several ions at the same time: the movement of one ion automatically results in that of one or more others in response. , The activation of this concerted ion migration mechanism is therefore sought to increase ionic conductivity . One explanation for obtaining this type of mechanism is the occupation, by the mobile ion, of both a high-energy site and a more stable low energy site.…”

Section: Discussionmentioning

confidence: 99%

Li_4.3AlS_3.3Cl_0.7: A Sulfide–Chloride Lithium Ion Conductor with Highly Disordered Structure and Increased Conductivity

et al. 2021

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Mixed anion materials and anion doping are very promising strategies to improve solid-state electrolyte properties by enabling an optimized balance between good electrochemical stability and high ionic conductivity. In this work, we present the discovery of a novel lithium aluminum sulfide–chloride phase, obtained by substitution of chloride for sulfur in Li3AlS3 and Li5AlS4 materials. The structure is strongly affected by the presence of chloride anions on the sulfur site, as the substitution was shown to be directly responsible for the stabilization of a higher symmetry phase presenting a large degree of cationic site disorder, as well as disordered octahedral lithium vacancies. The effect of disorder on the lithium conductivity properties was assessed by a combined experimental–theoretical approach. In particular, the conductivity is increased by a factor 103 compared to the pure sulfide phase. Although it remains moderate (10–6 S·cm–1), ab initio molecular dynamics and maximum entropy (applied to neutron diffraction data) methods show that disorder leads to a 3D diffusion pathway, where Li atoms move thanks to a concerted mechanism. An understanding of the structure–property relationships is developed to determine the limiting factor governing lithium ion conductivity. This analysis, added to the strong step forward obtained in the determination of the dimensionality of diffusion, paves the way for accessing even higher conductivity in materials comprising an hcp anion arrangement.

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Section: Discussionmentioning

confidence: 99%

Li_4.3AlS_3.3Cl_0.7: A Sulfide–Chloride Lithium Ion Conductor with Highly Disordered Structure and Increased Conductivity

et al. 2021

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“…From a certain level of disorder, migration involves several particles at the same time: the movement of one ion automatically results in that of one or more others in response. 49,50 The activation of this concerted ion migration mechanism is therefore sought to increase ionic conductivity. 51 One explanation for obtaining this type of mechanism is the occupation, by the mobile ion, of both a high-energy site and a more stable low energy site.…”

Section: Discussionmentioning

confidence: 99%

Li4.3AlS3.3Cl0.7: A Sulfide-Chloride Lithium Ion Conductor with a Highly Disordered Structure

Gamon¹,

Dyer²,

Duff³

et al. 2021

Preprint

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Mixed anion materials and anion doping are very promising strategies to improve solid-state electrolyte properties by enabling an optimized balance between good electrochemical stability and high ionic conductivity. In this work, we present the discovery of a novel lithium aluminum sulfide-chloride phase. The structure is strongly affected by the presence of chloride anions on the sulfur site, as this stabilizes a higher symmetry phase presenting a large degree of cationic site disorder, as well as disordered octahedral lithium vacancies, in comparison with Li-Al-S ternaries. The effect of disorder on the lithium conductivity properties was assessed by a combined experimental-theoretical approach. In particular, the conductivity is increased by a factor 103 compared to the pure sulfide phases. Although it remains moderate (10−6 S·cm-1), Ab Initio Molecular Dynamics and Maximum Entropy (applied to neutron diffraction data) methods show that disorder leads to a 3D diffusion pathway, where Li atoms move thanks to a concerted mechanism. An understanding of the structure-property relationships is developed to determine the limiting factor governing lithium ion conductivity. This analysis, added to the strong step forward obtained in the determination of the dimensionality of diffusion paves the way for accessing even higher conductivity in materials comprising an hcp anion arrangement.

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Toward understanding the second universality—A journey inspired by Arthur Stanley Nowick

et al. 2014

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In 1991, Arthur Stanley Nowick and his co-workers discovered a new universality, now known as nearly constant loss (NCL) or second universality. This mini-review, written in honor of A.S. Nowick, reports on the present authors' more recent endeavors and advances on their way toward understanding the second-universality phenomenon. In pursuit of that goal, new ideas and new data have led us to new questions and new answers. The essence of the new ideas was to consider time-dependent single-particle potentials, caused by Coulomb interactions and experienced by locally mobile ions. The dynamics of such ions were described in terms of a rate equation, and model conductivity spectra showing the NCL effect could be derived from it, with the help of linear response theory. New data corroborated the predictions made by the model. Also, our experimental data suggested a gradual transition, occurring with decreasing temperature, from a slightly activated NCL-type behavior to the non-activated features of the second universality. Two new questions have emerged. (i) Is it possible to quantify the transition mentioned above? (ii) Is there a crossover of the low-temperature, second-universality ionic conductivity from its characteristic linear frequency dependence to a quadratic one at low frequencies? New answers to our two questions can now be given, both of them in the affirmative. In particular, the crossover in the frequency dependence has been identified as an implication of the localization of the non-activated ionic motion.

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Broadband Conductivity Spectroscopy for Studying the Dynamics of Mobile Ions in Materials with Disordered Structures

Cited by 4 publications

References 69 publications

Li_4.3AlS_3.3Cl_0.7: A Sulfide–Chloride Lithium Ion Conductor with Highly Disordered Structure and Increased Conductivity

Li_4.3AlS_3.3Cl_0.7: A Sulfide–Chloride Lithium Ion Conductor with Highly Disordered Structure and Increased Conductivity

Li4.3AlS3.3Cl0.7: A Sulfide-Chloride Lithium Ion Conductor with a Highly Disordered Structure

Toward understanding the second universality—A journey inspired by Arthur Stanley Nowick

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Broadband Conductivity Spectroscopy for Studying the Dynamics of Mobile Ions in Materials with Disordered Structures

Cited by 4 publications

References 69 publications

Li4.3AlS3.3Cl0.7: A Sulfide–Chloride Lithium Ion Conductor with Highly Disordered Structure and Increased Conductivity

Li4.3AlS3.3Cl0.7: A Sulfide–Chloride Lithium Ion Conductor with Highly Disordered Structure and Increased Conductivity

Li4.3AlS3.3Cl0.7: A Sulfide-Chloride Lithium Ion Conductor with a Highly Disordered Structure

Toward understanding the second universality—A journey inspired by Arthur Stanley Nowick

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Product

Resources

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Li_4.3AlS_3.3Cl_0.7: A Sulfide–Chloride Lithium Ion Conductor with Highly Disordered Structure and Increased Conductivity

Li_4.3AlS_3.3Cl_0.7: A Sulfide–Chloride Lithium Ion Conductor with Highly Disordered Structure and Increased Conductivity