This study explores an innovative approach for selective lithium recovery using membrane-based capacitive deionization (MCDI) with electrode materials derived from spent Li-ion batteries. The mixed LiMn2O4/LiAlO2 cathode demonstrated superior performance, achieving 83.1% Li recovery efficiency and 38.15 mg/g deionization capacity. MCDI offers advantages such as fast processing, high removal capacities, and regeneration ability, contributing to a more sustainable lithium circular economy. The promising results lay a foundation for future research to optimize electrode materials and system design, addressing the increasing lithium demand while minimizing environmental impact.