Modified Stoney formula for in-situ lithiation stress measurement in thin-film Si electrode

LIU Peilin; LU Yuyang; ZHENG Dongchang; HE Linghui; NI Yong

doi:10.3969/j.issn.0253-2778.2020.12.009

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Open Access JUSTC Research Article

Modified Stoney formula for in-situ lithiation stress measurement in thin-film Si electrode

CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027, China

Funds: The work is supported by the National Natural Science Foundation of China (11672285), the Strategic Priority Research Program of the Chinese Academy of Sciences ( XDB22040502 ), China Postdoctoral Science Foundation (2018M642532), the Fundamental Research Funds for the Central Universities ( WK2090050046), the Collaborative Innovation Center of Suzhou Nano Science and Technology, and the Fundamental Research Funds for the Central Universities. Conflict of interest The authors declare no conflict of interest.

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https://doi.org/10.3969/j.issn.0253-2778.2020.12.009

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Author Bio:
Liu Peilin is a master student under the supervision of Prof. Ni Yong at University of Science and Technology of China (USTC). She received her bachelor’ s degree in Engineering Mechanics from North China University of Water Conservancy and Hydropower in 2014. Her research mainly focuses on the in- situ measurement of lithiation stress in thin-film Si electrode.
Corresponding author: Ni Yong is a Professor of Mechanics at University of Science and Technology of China ( USTC). He received his B. S. degree in Theoretical and Applied Mechanics in 2000 and Ph. D. degree in Solid Mechanics in 2004, both from USTC. From 2005 to 2009, he worked in Hong Kong University, National Institute of Standard and Technology, and Rutgers University as a visiting scholar and Research Associate, respectively. He joined the USTC faculty as a Professor of Mechanics in 2009. His research mainly focuses on mechanics of microstructured materials.
Publish Date: 30 December 2020

Abstract Full text PDF

Abstract

Abstract

The multi-beam optical stress sensor method combined with Stoney equation is an effective approach to measure in-situ average stress in thin film electrodes upon lithiation / delithiation. However, the classic Stoney formula is applicable only at low stress states. A modified Stoney formula for stress measurement in thin-film Si electrodes was applied to account for the combined effects of the Li concentration-dependent material properties and large substrate curvature change. The numerical results based on three-dimensional non-linear finite element model for the full coupling of large deformation and Li diffusion confirm the accuracy of the modified Stoney equation. Further, a critical condition for the curvature bifurcation was discussed, which should be avoid when using the modified Stoney equation.

Abstract

The multi-beam optical stress sensor method combined with Stoney equation is an effective approach to measure in-situ average stress in thin film electrodes upon lithiation / delithiation. However, the classic Stoney formula is applicable only at low stress states. A modified Stoney formula for stress measurement in thin-film Si electrodes was applied to account for the combined effects of the Li concentration-dependent material properties and large substrate curvature change. The numerical results based on three-dimensional non-linear finite element model for the full coupling of large deformation and Li diffusion confirm the accuracy of the modified Stoney equation. Further, a critical condition for the curvature bifurcation was discussed, which should be avoid when using the modified Stoney equation.