Combined influence of concentration-dependent properties, local deformation and boundary confinement on the migration of Li-ions in low-expansion electrode particle during lithiation

Abstract

In this article, a low expansion electrode particle is investigated for mechanical stresses during lithiation with intrinsic and extrinsic factors included. The stress states are estimated with local deformation, concentration dependent properties, and external constraints. It is observed that lithiation of an unconstrained electrode particle lead to reduced concentration gradient of Li-ions with increase in stress magnitude for a case where the particle show concentration dependent stiffening response. Whereas, the constrained expansion of the same electrode particle result in reduced and elevated concentration gradient at near-field and far-field locations, respectively. Influence of charging rate is also reported wherein limiting stress (threshold limit) is observed with increasing charging rate. Further, at elevated charging rates, a drastic reduction in concentration gradient is observed at the surface of the electrode particle.