Li-Ion Diffusion Correlations in LiAlGeO4: Quasielastic Neutron Scattering and Ab Initio Simulation

Sajan Kumar; Mayanak K. Gupta; Ranjan Mittal; Niina H. Jalarvo; Sanghamitra Mukhopadhyay; Rakesh Shukla; Srungarpu N. Achary; Alexander I. Kolesnikov; Avesh K. Tyagi; Samrath L. Chaplot

doi:10.1021/acsaem.2c02663

Li-Ion Diffusion Correlations in LiAlGeO₄: Quasielastic Neutron Scattering and Ab Initio Simulation

Sajan Kumar, Mayanak K. Gupta, Ranjan Mittal, Niina H. Jalarvo, Sanghamitra Mukhopadhyay, Rakesh Shukla, Srungarpu N. Achary, Alexander I. Kolesnikov, Avesh K. Tyagi, Samrath L. Chaplot

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

We investigated the impact of Li stoichiometry and host flexibility on Li⁺diffusion processes in LiAlGeO₄at the microscopic level using quasielastic neutron scattering (QENS) and ab initio molecular dynamics (AIMD) simulations. Using sufficiently long AIMD trajectories, we could simulate the observed QENS signal and identify the localized dynamics of Li in crystalline LiAlGeO₄. Such information is vital to identify the bottleneck of diffusion processes and design materials for battery application. Our AIMD simulations in LiAlGeO₄reveal that the Li⁺conductivity can be significantly improved by manipulating the Li stoichiometry and/or host flexibility via amorphization. We determined that excess Li stoichiometry enhances the Coulomb repulsion of neighboring Li sites and softens the host structure to enable faster Li⁺diffusion along the hexagonal c-axis. In the amorphous structure, random orientations of AlO₄and GeO₄polyhedral units create a wide distribution of intersite distances and significantly soften the host structure, greatly enhancing the Li⁺diffusion.

Original language	English
Pages (from-to)	14119-14126
Number of pages	8
Journal	ACS Applied Energy Materials
Volume	5
Issue number	11
DOIs	https://doi.org/10.1021/acsaem.2c02663
State	Published - Nov 28 2022

Funding

The use of the ANUPAM supercomputing facility at BARC is acknowledged. S.L.C. thanks the Indian National Science Academy for the financial support of the INSA Senior Scientist position. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory (ORNL).

Funders	Funder number
Indian National Science Academy

Keywords

ab initio molecular dynamics simulation
amorphous
diffusion
localized dynamics
quasielastic neutron scattering
vacancy

Access to Document

10.1021/acsaem.2c02663

Cite this

@article{ae35ef3010ab4eecb7555eff8e127123,

title = "Li-Ion Diffusion Correlations in LiAlGeO4: Quasielastic Neutron Scattering and Ab Initio Simulation",

abstract = "We investigated the impact of Li stoichiometry and host flexibility on Li+diffusion processes in LiAlGeO4at the microscopic level using quasielastic neutron scattering (QENS) and ab initio molecular dynamics (AIMD) simulations. Using sufficiently long AIMD trajectories, we could simulate the observed QENS signal and identify the localized dynamics of Li in crystalline LiAlGeO4. Such information is vital to identify the bottleneck of diffusion processes and design materials for battery application. Our AIMD simulations in LiAlGeO4reveal that the Li+conductivity can be significantly improved by manipulating the Li stoichiometry and/or host flexibility via amorphization. We determined that excess Li stoichiometry enhances the Coulomb repulsion of neighboring Li sites and softens the host structure to enable faster Li+diffusion along the hexagonal c-axis. In the amorphous structure, random orientations of AlO4and GeO4polyhedral units create a wide distribution of intersite distances and significantly soften the host structure, greatly enhancing the Li+diffusion.",

keywords = "ab initio molecular dynamics simulation, amorphous, diffusion, localized dynamics, quasielastic neutron scattering, vacancy",

author = "Sajan Kumar and Gupta, {Mayanak K.} and Ranjan Mittal and Jalarvo, {Niina H.} and Sanghamitra Mukhopadhyay and Rakesh Shukla and Achary, {Srungarpu N.} and Kolesnikov, {Alexander I.} and Tyagi, {Avesh K.} and Chaplot, {Samrath L.}",

year = "2022",

month = nov,

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doi = "10.1021/acsaem.2c02663",

language = "English",

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T2 - Quasielastic Neutron Scattering and Ab Initio Simulation

AU - Kumar, Sajan

AU - Gupta, Mayanak K.

AU - Mittal, Ranjan

AU - Jalarvo, Niina H.

AU - Mukhopadhyay, Sanghamitra

AU - Shukla, Rakesh

AU - Achary, Srungarpu N.

AU - Kolesnikov, Alexander I.

AU - Tyagi, Avesh K.

AU - Chaplot, Samrath L.

PY - 2022/11/28

Y1 - 2022/11/28

N2 - We investigated the impact of Li stoichiometry and host flexibility on Li+diffusion processes in LiAlGeO4at the microscopic level using quasielastic neutron scattering (QENS) and ab initio molecular dynamics (AIMD) simulations. Using sufficiently long AIMD trajectories, we could simulate the observed QENS signal and identify the localized dynamics of Li in crystalline LiAlGeO4. Such information is vital to identify the bottleneck of diffusion processes and design materials for battery application. Our AIMD simulations in LiAlGeO4reveal that the Li+conductivity can be significantly improved by manipulating the Li stoichiometry and/or host flexibility via amorphization. We determined that excess Li stoichiometry enhances the Coulomb repulsion of neighboring Li sites and softens the host structure to enable faster Li+diffusion along the hexagonal c-axis. In the amorphous structure, random orientations of AlO4and GeO4polyhedral units create a wide distribution of intersite distances and significantly soften the host structure, greatly enhancing the Li+diffusion.

AB - We investigated the impact of Li stoichiometry and host flexibility on Li+diffusion processes in LiAlGeO4at the microscopic level using quasielastic neutron scattering (QENS) and ab initio molecular dynamics (AIMD) simulations. Using sufficiently long AIMD trajectories, we could simulate the observed QENS signal and identify the localized dynamics of Li in crystalline LiAlGeO4. Such information is vital to identify the bottleneck of diffusion processes and design materials for battery application. Our AIMD simulations in LiAlGeO4reveal that the Li+conductivity can be significantly improved by manipulating the Li stoichiometry and/or host flexibility via amorphization. We determined that excess Li stoichiometry enhances the Coulomb repulsion of neighboring Li sites and softens the host structure to enable faster Li+diffusion along the hexagonal c-axis. In the amorphous structure, random orientations of AlO4and GeO4polyhedral units create a wide distribution of intersite distances and significantly soften the host structure, greatly enhancing the Li+diffusion.

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