Mechano-Electrochemical Analysis in Cylindrical Composition-Gradient Electrodes with Varying Young's Modulus of Lithium-Ion Battery

Abstract

Composition-gradient electrode material (CGEM) is one of the most promising materials in lithium-ion battery, and this paper studies its performance from the stress analysis. The finite deformation theory and the stress-induced diffusion hypothesis are adopted to establish the constitutive equations, and the nonlinear influence of finite deformation is considered. The aim is to investigate diffusion-induced stresses (DISs) generated in a cylindrical composition-gradient electrode with the slope of −0.5 for Young's modulus E(R). Compared with stress distributions in a homogeneous electrode, CGEM is able to make the stress fields smaller and flatter and improve the state of charging (SOC). Then we change the elastic modulus of electrode materials from 10GPa to 150GPa gradually, and those advantages still exist. Finally, diffusion-induced buckling of cylindrical electrodes is analyzed and CGEMs make the cylindrical electrode more difficult to buckle. Therefore, many electrode materials can be made into CGEMs to prevent the electrode from cracking. The results can provide a theoretical guidance for the design of CGEMs.