We simulate the mechanical–chemical coupling during delithiation and relaxation of a cathode in a solid-state lithium-ion battery. Contact loss at the interface between the active particle and the solid electrolyte is considered. Uphill diffusion is observed during delithiation and relaxation. This phenomenon is explained by analyzing the total chemical potential and its two components. Contact loss at the interface greatly influences the stress and stress gradient in the active particle. As delithiation continues, the stress and stress gradient grow considerably, and the mechanical part of the total chemical potential becomes dominant over the chemical part of it. In the latter stage of delithiation, the influence of the incomplete interfacial constraint on the stress becomes dominant, while the effect of the concentration gradient becomes negligible. After relaxation, the concentration and stress gradients increase in a particle with contact loss. The influence of the degree of contact loss on the mechanical–chemical coupling is investigated. The overall tensile stress in the active particle increases with decreasing contact loss, causing a sharp decrease in local concentration. We also check the effect of the elastic modulus of the solid electrolyte on the coupling of the active material. A rigid solid electrolyte with a higher elastic modulus more strongly restricts the active particle, leading to a higher tensile stress, a larger stress gradient, and a greater concentration gradient.

我们模拟了固态锂离子电池中阴极脱锂和弛豫过程中的机械-化学耦合。考虑了活性颗粒和固体电解质之间界面处的接触损失。在脱锂和弛豫期间观察到向上扩散。这种现象可以通过分析总化学势及其两个分量来解释。界面处的接触损失极大地影响了活性颗粒中的应力和应力梯度。随着脱锂的继续，应力和应力梯度显着增加，总化学势的机械部分变得比化学部分占主导地位。在脱锂后期，不完全界面约束对应力的影响占主导地位，而浓度梯度的影响则可以忽略不计。松弛后，粒子中的浓度和应力梯度会随着接触损失而增加。研究了接触损耗程度对机械-化学耦合的影响。活性颗粒中的总拉伸应力随着接触损失的减少而增加，导致局部浓度急剧下降。我们还检查了固体电解质的弹性模量对活性材料耦合的影响。具有较高弹性模量的刚性固体电解质对活性粒子的约束更强，导致更高的拉伸应力、更大的应力梯度和更大的浓度梯度。研究了接触损耗程度对机械-化学耦合的影响。活性颗粒中的总拉伸应力随着接触损失的减少而增加，导致局部浓度急剧下降。我们还检查了固体电解质的弹性模量对活性材料耦合的影响。具有较高弹性模量的刚性固体电解质对活性粒子的约束更强，导致更高的拉伸应力、更大的应力梯度和更大的浓度梯度。研究了接触损耗程度对机械-化学耦合的影响。活性颗粒中的总拉伸应力随着接触损失的减少而增加，导致局部浓度急剧下降。我们还检查了固体电解质的弹性模量对活性材料耦合的影响。具有较高弹性模量的刚性固体电解质对活性粒子的约束更强，导致更高的拉伸应力、更大的应力梯度和更大的浓度梯度。