Electrochemically switched ion exchange (ESIX) is an effective technology for extracting high-value-added ions from dilute solutions. This study focuses on Li

+

extraction by employing a comprehensive model to analyze interaction between fluidic dynamics

electric field and ion transport. The model combines Butler-Volmer equation modified by electroactive site concentration

Nernst-Planck equation and Navier-Stokes equation. It is found that the chamber width affects solution phase resistance

thereby altering the potential distribution and influencing the current distribution within the membrane. A narrow chamber increases current density in the solid phase of the membrane

enhancing Li

+

extraction. The solution flow-field not only enhances convective transport but also increases the current density in the solid phase

promoting Li

+

extraction. There is a synergistic effect between fluid-flow-field and electric-field for ion separation

which is only significant when the chamber width is greater than 2 mm. The synergistic mechanism differs from that in the capacitive deionization system. Therefore

the performance decline caused by a wide chamber can be compensated for by increasing the fluid-flow rate

utilizing the synergistic effect between the fluid-flow-field and electric-field to optimize the lithium extraction efficiency in the ESIX system.