力学所Seminar 779
题目：Understanging and mitigating diffusion-induced-stresses and fracture in lithium ion battery electrodes
报告人：郑仰泽 教授(美国肯塔基大学)
时间：2013年6月25日（周二)9:30
地点：延长校区应用数学和力学研究所
主办部门：理学院力学所

摘要： Most lithium ion battery electrodes experience large volume changes caused by concentration changes within the host particles during charging and discharging. Electrode failure, in the form of fracture or decrepitation, can occur as a result of repeated volume changes. In this presentation, I will provide an overview of our recent work on modeling the evolution of concentration, stress, and strain energy within a spherically- or cylindrically-shaped electrode element under various charging-discharging conditions. We show that a dimensionless parameter, the electrochemical Biot number, may be used to characterize stress and strain energy evolution in an electrode. In particular, the electrochemical Biot number determines the maximum stress and strain energy. Based on analytic solutions, we propose tensile stress and strain energy based criteria for the initiation and propagation of cracks in insertion electrodes. These criteria may help guide the development of new materials for lithium ion batteries with enhanced durability and performance. We will also discuss other effects, such as moving phase boundaries, surface and interface energies, and concentration-dependent elastic modulus, on stress and strain energy evolution in insertion electrodes, as well as stress-induced whisker growth in lithium ion battery electrodes, crack pattern formation in silicon thin film electrodes, and a coupled chemical-mechanical degradation model for lithium ion battery electrodes. Finally, we will discuss our recent concept of using liquid metals as self-healing negative electrodes for lithium ion batteries.