The effects of electrode particle morphology on electrochemical-mechanical performance for lithium-ion battery

Abstract

To improve the performance of lithium-ion batteries, electrode particles have been designed in various morphologies, with the cylindrical structure being one of the more common electrode particle shapes. However, compared to conventional spherical particles, the advantages of cylindrical particles have not been fully understood. This study develops an electrochemical-mechanical coupled model for the two morphologies of electrode particles—cylindrical and spherical—to analyze and compare their diffusion-induced stresses and electrochemical performance. The results show that the stress levels in cylindrical electrode particles are safer than spherical electrode particles as the particle size decreases. Under potentiostatic operation or the same charge/discharge rates, cylindrical particles demonstrate inferior charge state of charge (SOC) compared to spherical particles at larger sizes, but the disparity diminishes progressively as particle dimensions decrease. Under the same charging/discharging current magnitudes, cylindrical electrode particles have a higher charge SOC, and that increases with a higher aspect ratio. Consequently, the design of slender cylindrical electrode particles offers a promising strategy to simultaneously improve both electrochemical performance and mechanical stability in lithium-ion batteries.