A Chemo-Elastoplastic Analysis of Anisotropic Swelling in an SnO2 Nanowire Under Lithiation

Abstract

A parametric study is carried out to shed iight on the elastoplastic behavior of a nanowire under lithiation. The Li-ion diffusivity is assumed to be significantly higher at near-saturation than at diiute concentration. It leads to the prediction of an Li-ion diffusion jam and consequently a topologicaliy steep step moving along the wire. The analysis shows that the different plastic flow rates due to the different constraint conditions along the longitudinal and radial directions result in apparent anisotropic volume expansion. Either lower yield strength, smaller strain hardening ratio, or higher charging rate would cause greater swelling anisotropy. The numerical results are compared with the expérimentai observation of an SnO2 nanowire (Huang et al,