TY - JOUR
T1 - Capturing the stress evolution in electrode materials that undergo phase transformations during electrochemical cycling
AU - Wang, Bo
AU - Réthoré, Julien
AU - Aifantis, Katerina E.
N1 - Funding Information:
The authors are grateful to the National Science Foundation for supporting this work through the CMMI grant (CMMI-1762602).
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/8/1
Y1 - 2021/8/1
N2 - The present work sheds light on the stresses generated in a spherical particle subjected to phase transformations during ion-insertion. In order to account for the physical process that occurs during electrochemical cycling, the models used are those of small deformation and account for the effects of phase transformation, chemo-mechanical coupling and concentration-dependent material properties. The two-phase lithiation is modeled by the Cahn–Hilliard equation. It is found that the DISs arise from the inhomogeneous volume expansions resulting from Li concentration gradients and the hydrostatic stress facilitates the diffusion of Li-ions under elastic deformation while it hinders diffusion in the plastic case. When the elastic modulus is reduced the magnitude of the diffusion-induced stress decreases but the strain increases under elastic deformation whereas the opposite occurs for the plastic case. Furthermore, if the electrode is assumed to undergo strain softening during plastic deformation, smaller stresses and higher plastic strains are predicted than when strain hardening is assumed. The novelty of this work is that the proposed models highlight the importance of chemo-mechanical coupling effects, concentration-dependent material properties and plastic deformation on diffusion-induced stresses. These findings render prospective insights for designing next-generation mechanically stable phase transforming electrode materials.
AB - The present work sheds light on the stresses generated in a spherical particle subjected to phase transformations during ion-insertion. In order to account for the physical process that occurs during electrochemical cycling, the models used are those of small deformation and account for the effects of phase transformation, chemo-mechanical coupling and concentration-dependent material properties. The two-phase lithiation is modeled by the Cahn–Hilliard equation. It is found that the DISs arise from the inhomogeneous volume expansions resulting from Li concentration gradients and the hydrostatic stress facilitates the diffusion of Li-ions under elastic deformation while it hinders diffusion in the plastic case. When the elastic modulus is reduced the magnitude of the diffusion-induced stress decreases but the strain increases under elastic deformation whereas the opposite occurs for the plastic case. Furthermore, if the electrode is assumed to undergo strain softening during plastic deformation, smaller stresses and higher plastic strains are predicted than when strain hardening is assumed. The novelty of this work is that the proposed models highlight the importance of chemo-mechanical coupling effects, concentration-dependent material properties and plastic deformation on diffusion-induced stresses. These findings render prospective insights for designing next-generation mechanically stable phase transforming electrode materials.
KW - Chemo-mechanical coupling
KW - Concentration-dependent elastic modulus
KW - Electrodes
KW - Phase transformation
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U2 - 10.1016/j.ijsolstr.2021.03.019
DO - 10.1016/j.ijsolstr.2021.03.019
M3 - Article
AN - SCOPUS:85104354870
VL - 224
JO - International Journal of Solids and Structures
JF - International Journal of Solids and Structures
SN - 0020-7683
M1 - 111032
ER -