In recent years, the transition to fully electric vehicles has emerged as one of the most effective strategies to combat climate change and reduce environmental pollution. Among the various energy storage technologies, lithium-ion batteries are the most widely used in electric vehicles due to their high energy density and reliability. This thesis aims to explore how the performance of electric vehicles powered by lithium-ion batteries can be enhanced through the integration of sodium-ion batteries. Specifically, the study will investigate the potential benefits of combining lithium-ion and sodium-ion batteries, with a primary focus on reducing the C-rate experienced by the lithium battery.