(103d) Lithium Ion Batteries for Energy Storage Applications: Modeling Diffusion-Induced Stresses in Nanostructured Electrode : Modeling Diffusion-Induced Stresses in Nanostructured Electrode

Developing lithium ion batteries with high power and energy density for wide range of applications is currently under intense research worldwide. Mechanical degradation of the battery electrodes due to lithium ion diffusion during charging and discharging operations is a major hurdle in development of durable lithium ion battery. When lithium is inserted into either the positive or negative electrode, a large volume change on the order of a few to several hundred percent can occur. This volume change due to diffusion induced stresses (DISs) leads to mechanical degradation of the electrode material. Our work is aimed at developing nanostructured electrodes with enhanced durability. Upon decreasing size of the electrode particles, the ratio of surface area to volume increases tremendously. Thus, surface energy and surface stress may play an important role in mitigating DISs in nanostructured electrodes. In this work, we establish relationships between the surface energy, surface stress, and the magnitude of DISs in nanowires. We show that DISs, especially the tensile stresses, can decrease significantly due to the surface effects. Our model also establishes a relationship between stress and the nanowire radius. We show that, with decreasing size, the electrode material will be less prone to mechanical degradation, leading to an increase in the life of lithium ion batteries