Strain effects on lithium ion diffusion in various crystal structures

Abstract

Electrodes of lithium-ion batteries (LIBs) work in a complex force environment with volume changes during charging and discharging, which greatly affect the electrochemical performance of LIBs. To investigate the effect of volumetric strain on Li diffusion under mechano-electro-chemical coupling, the activation energies of Li diffusion for four types of face-centered cubic structures, Li₃M, Li₂MN, Li₂MNY₆ and Li₃MY₆, and four conventional types of structures, olivine, spinel, LISICON and layered structures, were analyzed with the effect of strain under different conditions. The results show that tensile strain favors lithium diffusion, that is the effect of in-plane strain on lithium diffusion is greater than that of uniaxial strain. Furthermore, the transition metal valence change induced by strain also has a significant effect on lithium diffusion.