Influences of carbon nanotubes in Tin nanocomposite active plate on the diffusion induced stresses and curvature in bilayer lithium-ion battery electrodes

Abstract

Structure integrity of electrodes can be broken by the diffusion induced stresses (DISs) leading to a significant degradation of storage capacity and cycling stability of lithium-ion batteries. In this paper, the effects of adding carbon nanotubes (CNTs) into the Tin (Sn)-based nanocomposite active plate bonded to the current collector on the DISs and curvature of bilayer electrodes are numerically investigated. A physics-based hierarchical modeling approach based on the Mori-Tanaka micromechanical method is developed to estimate the effective properties of CNT-Sn nanocomposite active plate. The predictions of the micromechanics method are in good agreement with the experimental data. It is shown that the CNTs embedded into the active plate have the significant contribution to the mechanical performances of lithium-ion battery electrodes. Adding the CNTs into the nanocomposite active plate can alleviate the overall stress and curvature of the bilayer electrodes. The influences of volume fraction, length, diameter, non-straight shape and agglomeration of CNTs as well as the geometric parameters of the bilayer electrode on the built-in stresses and flexural deformation are extensively discussed. The overall stresses and curvature of the bilayer electrodes can be further decreased by aligning the CNTs into the nanocomposite active plate. The present work can provide a novel angle of view for designing and evaluating the bilayer electrodes containing CNT-metal nanocomposite active plates.