The Coupling of Strain and Lithium Diffusion: A Theoretical Model Based on First-Principles Calculations

Abstract

© 2015 The Electrochemical Society. Most electrodes undergo volume changes in lithium-ion batteries, and it turns out that the volume changes also significantly affect lithium diffusion kinetics based on first-principles calculations. To study the mechano-electro-chemical coupling, a theoretical model of spherical electrode has been developed and the effect of strain ondiffusion coefficient is explicitly considered. The results show that strain-enhanced diffusion greatly alleviates diffusion-induced stresses, and the lithiation and delithiation are extremely asymmetric in lithium concentration distribution and stresses due to asymmetrical changes of diffusion coefficient with time and positions along the radial direction.