<p>Amidst rising global lithium demand, the efficient utilization of salt lake brines is imperative for ensuring a sustainable supply. This study presents an electrochemical lithium extraction system using a LiMn₂O₄ (LMO) working electrode and a lead counter electrode, to recover lithium from low-concentration simulated brine. Characterization techniques such as SEM and XRD were employed to analyze material structure and performance. The results indicate that the synthesized LMO electrode exhibits high purity and crystallinity, with two distinct redox peaks in lithium-containing solutions corresponding to lithiation and delithiation processes. It exhibits excellent cycling stability, retaining a specific capacity above 105&#xa0;mAh/g after 20 cycles in 1.0&#xa0;M Li₂SO₄ solution, with a coulombic efficiency stable at 97.5%. In a mixed solution of Li/Na/Mg at a ratio of 1:1:1, charge–discharge specific capacity reaches approximately 120&#xa0;mAh/g, while maintaining over 95% coulombic efficiency—showing excellent cycle stability and high selectivity for Li⁺, unaffected by coexisting ions like Na⁺ or Mg²⁺. Experiments in simulated brine validated the feasibility of the LMO//Pb lithium extraction system; after five extractions, Li⁺ concentration increased from 0.76&#xa0;g/L to 1.07&#xa0;g/L with an effective separation factor (Li–Na) of 226, demonstrating successful extraction and enrichment of lithium. Although LMO electrode performance is somewhat affected under low-lithium concentrations and its selectivity for Mg²⁺ decreases during cycling, overall it shows significant potential in electrochemical lithium extraction—providing important insights for developing green and efficient technologies for extracting lithium from salt lake brines.</p>