Investigating microstructural features of the carbon nanotube-aluminum hybrid active plate on diffusion induced stresses in the bilayer electrode with initial stretching

Various types of batteries are produced to support years of service for implantable medical devices. Evaluation of internal stresses in nanoparticle-contained electrodes for lithium-ion batteries (LIBs) is a fundamental step toward enhancing their durability. In this research, diffusion induced stresses (DISs) in the bilayer electrode consisted of the carbon nanotube (CNT)-aluminum (Al) nanocomposite active plate bonded to the current collector are investigated. Modeling the DIS is performed by applying the initial stretching on the CNT-Al active plate. Effective properties of CNT-filled Al nanocomposites are calculated using micromechanics models in which the formation of interfacial carbide between the Al and CNT is considered. The role of important microstructural features including amount, length, diameters, curved structure and dispersion type of CNTs, and the thickness and property of interphase in DISs is examined to provide design insights for LIB electrodes. The blending of straight CNTs with a high aspect ratio significantly reduces the tensile stress in the current collector, both compressive and tensile stresses in the nanocomposite active plate and especially the stress drop at the collector/plate interface. Moreover, the DISs can be alleviated by the formation of a stiff and thick interphase between the Al and nanotubes. The CNT-contained electrode with a stretched active plate exhibits lower internal stresses.