当前位置: X-MOL 学术Int. J. Solids Struct. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Capturing the stress evolution in electrode materials that undergo phase transformations during electrochemical cycling
International Journal of Solids and Structures ( IF 3.6 ) Pub Date : 2021-03-24 , DOI: 10.1016/j.ijsolstr.2021.03.019
Bo Wang , Julien Réthoré , Katerina E. Aifantis

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.



中文翻译:

捕获在电化学循环过程中经历相变的电极材料中的应力演化

本工作揭示了在离子插入过程中经历相变的球形颗粒中产生的应力。为了考虑到电化学循环过程中发生的物理过程,使用的模型是变形较小的模型,并考虑了相变,化学机械耦合和浓度依赖性材料特性的影响。两相锂化通过Cahn–Hilliard方程建模。发现DIS是由Li浓度梯度引起的不均匀的体积膨胀引起的,并且流体静应力促进了锂离子在弹性变形下的扩散,同时阻碍了在塑料外壳中的扩散。当弹性模量减小时,扩散引起的应力的大小减小,但在弹性变形下应变增加,而塑料壳体则相反。此外,如果假定电极在塑性变形期间经历了应变软化,则与假定应变硬化时相比,可以预测到较小的应力和较高的塑性应变。这项工作的新颖之处在于,所提出的模型突出了化学机械耦合效应,浓度依赖性材料特性和塑性变形对扩散诱发应力的重要性。这些发现为设计下一代机械稳定的相变电极材料提供了前瞻性的见识。如果假定电极在塑性变形过程中发生了应变软化,则与假设应变硬化时相比,可以预测到较小的应力和较高的塑性应变。这项工作的新颖之处在于,所提出的模型突出了化学机械耦合效应,浓度依赖性材料特性和塑性变形对扩散诱发应力的重要性。这些发现为设计下一代机械稳定的相变电极材料提供了前瞻性的见识。如果假定电极在塑性变形过程中发生了应变软化,则与假设应变硬化时相比,可以预测到较小的应力和较高的塑性应变。这项工作的新颖之处在于,所提出的模型突出了化学机械耦合效应,浓度依赖性材料特性和塑性变形对扩散诱发应力的重要性。这些发现为设计下一代机械稳定的相变电极材料提供了前瞻性的见识。浓度依赖性的材料特性和扩散引起的应力下的塑性变形。这些发现为设计下一代机械稳定的相变电极材料提供了前瞻性的见识。浓度依赖性的材料特性和扩散引起的应力下的塑性变形。这些发现为设计下一代机械稳定的相变电极材料提供了前瞻性的见识。

更新日期:2021-04-18
down
wechat
bug