Electrostatic-field-triggered stress in the lithiation of carbon-coated silicon

Abstract

The traditional viewpoint “the more the lithiation reaction, the bigger the growth stress” is proved to be improper through the simulation of lithiation reaction of carbon-coated silicon particle in the presence of electrostatic field. In the simulation, a positive correlation between growth stresses and charge density is observed and coincides with the experiment results in Pharr's work. Simulation results also indicate that the growth stresses consist of lithiation-reaction-induced stress (LRIS) and field-triggered stress (FTS). FTS is always neglected but can be comparable to, or even bigger than the LRIS in the initial stage of lithiation reaction. The physical mechanism for the formation of FTS is uncovered based on the standpoint of energy conservation and transformation. The FTS needs to be considered seriously because it can bring much more serious damage to the lattice structure of silicon especially in the development of lithium ion battery featuring rapid charging.