X-ray study of lithium disilicate glass: High pressure densification and polyamorphism

Buchner, Silvio; Pereira, Altaïr Soria; Lima, J.C. de; Balzaretti, Naira Maria

doi:10.1016/j.jnoncrysol.2014.01.003

Cited by 25 publications

(37 citation statements)

References 18 publications

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“…The distances of Si-O, O-O, and Si-Si are in good agreement with those of shocked SiO 2 glasses obtained from an X-ray diffraction, 44 and densified Li 2 O-2SiO 2 glasses at high pressures. 45,46 The first peak at a radius of 1.95 Å in the partial Li-O RDF shown in Fig. 4d corresponds to a shoulder in the calculated total RDF shown in Fig.…”

Section: Resultsmentioning

confidence: 92%

Fast Li-Ion Transport in Amorphous Li₂Si₂O₅: An Ab Initio Molecular Dynamics Simulation

Lei

Wang

Huang

2016

J. Electrochem. Soc.

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The present study reports an ab-initio molecular dynamics (AIMD) simulation of ionic diffusion in the amorphous Li 2 Si 2 O 5 in a temperature range of 573-823 K. The results show that the amorphous Li 2 Si 2 O 5 is primarily a Li + conductor with negligible O 2− and Si 4+ contributions. The obtained activation energy of 0.47 eV for Li + diffusion is higher than Na + in the analogue amorphous Na 2 Si 2 O 5 , but close to other types of Li + conductors. The predicted Li + conductivity is on the order of 10 −2 S·cm −1 at 623-823 K. Our simulations also reveal that Li + in the amorphous Li 2 Si 2 O 5 diffuses via a hopping mechanism between the nearest sites in the channels formed by two adjacent SiO 4 layers. © The Author Solid-state lithium-ion batteries (SSLIBs) are envisioned to be the next-generation high-power and high-capacity energy storage devices with far less safety and temperature stability issues experienced by the conventional liquid-based counterparts.1-18 As a key component of SSLIBs, the electrolyte should possess a high Li + conductivity (σ) at room temperature and low activation energy (E a ) for use over a broad range of operating temperatures. In the meanwhile, properties such as electrochemical stability over a wide working voltage window and chemical stability against electrodes (layered cathode and Li metal anode) should also be preferred. So far, a broad range of materials have been investigated as potential solid Li 6-8 and sulfide-based compounds with higher ionic conductivities such as the thio-LISICON group (Li 7 P 3 S 11 , σ = 3.2-17 × 10 −3 Scm −1 at 25 Therefore, the aim of the present study is to investigate the ionic transport property, in particularly Li + conductivity, in the amorphous Li 2 Si 2 O 5 that is a close analogue to the known Na + -conductoramorphous Na 2 Si 2 O 5 via a theoretical ab-initio molecular dynamics (AIMD) approach. We selected 573-823 K as the temperature range for the simulation because we have experimentally observed reasonably high conductivity from the amorphous Li 2 Si 2 O 5 in this temperature range. With the help of this AIMD simulation, we will be able to gain the insights into the nature of the observed conductivity. We believe that the outcome of this work is not only important to the understanding of ionic conduction mechanism in solid-state amorphous Li 2 Si 2 O 5 , but also to the identification of new solid-state electrolytes for future solid-state Li-ion batteries. 2 ) valence electrons with a plane wave cutoff energy of 500 eV. The atomic positions were optimized to the level of the maximum ionic force ≤0.02 eV Å −1 . A Verlet algorithm was integrated with Newton's equations of motion at a time step of 2 fs for a total simulation time of 50 ps, i.e., 25,000 steps performed on an NVT ensemble. The frequency of the temperature oscillations was controlled by the Nosé mass during the simulations. A supercell of 2 × 1 × 2 unit cell containing 144 atoms was chosen for a k-point sampling at the -point.Initial configurations.-The simulations started...

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Section: Resultsmentioning

confidence: 92%

Fast Li-Ion Transport in Amorphous Li₂Si₂O₅: An Ab Initio Molecular Dynamics Simulation

Lei

Wang

Huang

2016

J. Electrochem. Soc.

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“…The process of permanent densification in glasses is mostly connected with the decrease of the interatomic bond angle and the gradual increase of the average atomic coordination, which was named a polyamorphism of glass structure and was intensively investigated for silica glass by Raman scattering experiments, XRD, and molecular dynamic simulation [27][28][29][30][31][32]. Lower strain rate and at the same time longer time of loading (see the inserted graphs in Fig.…”

Section: Resultsmentioning

confidence: 99%

Densification contribution as a function of strain rate under indentation of terbium-doped aluminophosphate glass

et al. 2015

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In this work, the strain rate effect on the deformation processes under Berkovich indentation of Tbdoped aluminophosphate glass has been investigated. It is shown that both densification and shear flow, adopted as main mechanisms of plastic deformation for oxide glasses, are strain rate sensitive. Moreover, the shear flow is assumed to be responsible for the strain rate sensitivity of densification. The densification contribution to the total plastic deformation is found to be greater for lower strain rate, and the same tendency is observed for the plastic flow. This, in turn, leads to the influence of the strain rate on the hardness values, manifesting as a softening of the glassy matrix with the decrease of strain rate caused by more intensive development of the densification and shear flow. The decrease of hardness with load increase is attributed to the involving and increasing contribution of the shear flow and fracture to the total deformation process.

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“…High pressure (7.7 GPa) densification of lithium disilicate glasses previously resulted changes in glass structure similar to that in the metasilicate phase. This type of polyamorphism if present would have a major role in the crystallization process [35]. Densification was also carried out at 800 • C under a 50 MPa pressure to avoid breaking the SPS graphite mold under high pressure and temperature.…”

Section: Xxxe9mentioning

confidence: 99%

The effect of spark plasma sintering on lithium disilicate glass-ceramics

et al. 2015

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X-ray study of lithium disilicate glass: High pressure densification and polyamorphism

Cited by 25 publications

References 18 publications

Fast Li-Ion Transport in Amorphous Li₂Si₂O₅: An Ab Initio Molecular Dynamics Simulation

Fast Li-Ion Transport in Amorphous Li₂Si₂O₅: An Ab Initio Molecular Dynamics Simulation

Densification contribution as a function of strain rate under indentation of terbium-doped aluminophosphate glass

The effect of spark plasma sintering on lithium disilicate glass-ceramics

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X-ray study of lithium disilicate glass: High pressure densification and polyamorphism

Cited by 25 publications

References 18 publications

Fast Li-Ion Transport in Amorphous Li2Si2O5: An Ab Initio Molecular Dynamics Simulation

Fast Li-Ion Transport in Amorphous Li2Si2O5: An Ab Initio Molecular Dynamics Simulation

Densification contribution as a function of strain rate under indentation of terbium-doped aluminophosphate glass

The effect of spark plasma sintering on lithium disilicate glass-ceramics

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Product

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Fast Li-Ion Transport in Amorphous Li₂Si₂O₅: An Ab Initio Molecular Dynamics Simulation

Fast Li-Ion Transport in Amorphous Li₂Si₂O₅: An Ab Initio Molecular Dynamics Simulation