Diffusion-Induced Stress within Core-Shell Structures and Implications for Robust Electrode Design and Materials Selection

The life of lithium-ion batteries is related to the mechanical expansion and contraction of active materials along with solvent decomposition at the active material surfaces-lithium-ion batteries would not work if a protective shell did not cover the electroactive core of the positive and negative electrode materials. Exposure of the active core leads to cell degradation. Under what conditions are the protective (outer shell) materials compromised? In addition to reviewing literature that is relevant to answering this question, we derive governing equations and provide numerical and analytic results in this work to render a qualitative response to this question, and we identify open questions that limit the quantitative application of modeling results to these systems.