During battery operation, Li flows into and out of electrode particles, causing microstructural changes and deformation-induced degradation. A variety of models have been proposed to interpret these mechanical and microstructural changes, but they lack of proper input materials' properties and direct experimental supports. To address this challenge, we developed �atomically informed� battery mechanics models by integrating density functional theory (DFT) predicted mechanical properties into continuum models to predict diffusion induced deformation and stress evolution and make direct comparisons with experiments. Based on DFT calculations, we found many electrode materials change their elastic properties, fracture energies, interfacial properties, and bonding natures upon lithiation.This talk will focus on computation-aided design of mechanically robust Si composite electrodes, in which the interfacial properties become very critical. Various interfaces, such as Si/Cu, Si/C, and Si/coating interface properties are predicted from density functional theory (DFT) and ab-initio molecular dynamics (AIMD) calculations. For example, it was found that Li tends to segregate at the Si/Cu interface, but not at the Si/amorphous-C interface; and the adhesion at the Si/sp2-bonded carbon interface is intrinsically weak, but can be improved by functioning groups.  These predicted properties serve as inputs for continuum level of modeling in order to compare directly with experiments and give morphology design guidelines.

Integrating state of charge (SOC) dependent material properties into Li-ion battery failure modeling

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.