Thermal and diffusion‐induced stresses in crystalline solids

1995 ◽  
Vol 77 (1) ◽  
pp. 127-134 ◽  
Author(s):  
I. V. Belova ◽  
G. E. Murch
Keyword(s):  
Crystalline Solids ◽  
Induced Stresses ◽  
And Diffusion

scholarly journals Phase Field Modeling of Coupled Phase Separation and Diffusion-Induced Stress in Lithium Iron Phosphate Particles Reconstructed From Synchrotron Nano X-ray Tomography

2019 ◽  
Vol 16 (4) ◽  
Author(s):  
Linmin Wu ◽  
Vincent De Andrade ◽  
Xianghui Xiao ◽  
Jing Zhang
Keyword(s):  
Phase Separation ◽  
Phase Field ◽  
Lithium Iron Phosphate ◽  
Iron Phosphate ◽  
Ion Concentration ◽  
Concentration Difference ◽  
X Ray ◽  
Aspect Ratios ◽  
Induced Stresses ◽  
And Diffusion

In this study, the phase separation phenomenon and diffusion-induced stresses in lithium iron phosphate (LiFePO4) particles under a potentiostatic discharging process have been simulated using the phase field method. The realistic particles reconstructed from synchrotron nano X-ray tomography along with idealized spherical and ellipsoid shaped particles were studied. The results show that stress and diffusion process in particles are strongly influenced by particle shapes, especially at the initial lithiation stage. Stresses in the realistic particles are higher than that in the idealized spherical ones by at least 30%. The diffusion-induced hydrostatic stress has a strong relationship with lithium ion concentration. The hydrostatic stresses and first principal stresses tend to shift from lower values to higher values as the particle takes in more lithium ions. Additionally, the diffusion-induced stresses are related to the maximum concentration difference in the particle. High concentration difference will cause high stresses. In ellipsoid particles, the stress levels increase with the aspect ratios. The model provides a design tool to optimize the performance of cathode materials with phase separation phenomena.

Effect of Irreversible Electrochemical Reaction on Diffusion and Diffusion-Induced Stresses in Spherical Composition–Gradient Electrodes

2019 ◽  
Vol 75 (1) ◽  
pp. 55-63
Author(s):  
Kai Zhang ◽  
Bailin Zheng
Keyword(s):  
Electrochemical Reaction ◽  
Composition Gradient ◽  
Electrochemical Performances ◽  
Transition Form ◽  
Capacity Fading ◽  
Induced Stresses ◽  
The Difference ◽  
And Diffusion ◽  
Positive Effect ◽  
Heterogeneous Factor

AbstractComposition–gradient electrodes have been proved to have excellent electrochemical performances. The effect of irreversible electrochemical reaction on diffusion and diffusion-induced stresses in such electrodes is investigated. The diffusion equation and mechanical equation considering the electrochemical reaction and the heterogeneous factors are derived, and the distributions of lithium (Li) concentration and stresses in a spherical electrode are obtained under potentiostatic charging. The results indicate that the electrochemical reaction will slow down the diffusion process and enhance the stresses of the electrode. However, the heterogeneous factors of the electrochemical reaction could provide a positive effect on the stresses, which means that the heterogeneous factor is conducive to avoid capacity fading of the battery. The results suggest that the composition–gradient electrodes could be designed to have a decreasing transition form of forward reaction rate and an increasing transition form of the difference of atomic volume between reactants and the reaction product.

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