Mechanical reliability of alloy-based electrode materials for rechargeable Li-ion batteries

Lithium alloys with metallic or semi-metallic elements are attractive candidate materials for the next-generation high-capacity rechargeable Li-ion battery anodes, due to their large specific and volumetric capacities. The key challenge in the application of these materials has been the very large volume changes, and the associated stress buildup and failure during insertion and extraction of lithium. While such stress buildup bears resemblance to the process of thermo-stress development, a phenomenon relatively well-understood, the physics involved in these alloy-based electrodes is much more complex in nature, more challenging to address, and richer in the variety of influencing factors. The reasons not only lie in the fact that the mechanical deformations are much larger, but also arise from the fact that the processes entail interactions among mass diffusion, chemical reactions, non-linear plastic flow and material property evolutions. In this paper, we present a review of some of the fundamental issues and the latest research related to the mechanical reliability of such alloy-based anode materials, with a focus on Li/Si, a material with the highest known theoretical energy storage capacity. The review primarily concerns continuum-level analyses, with relevant experimental data and atomistic-level results as input.