Application of a Flow-Type Electrochemical Lithium Recovery System with λ-MnO₂/LiMn₂O₄: Experiment and Simulation

Due to the rapid growth of the global electric vehicle and electronics markets, lithium has become an indispensable resource for our lifestyle, and numerous methods for securing lithium are being actively attempted. For fast and environment-friendly lithium extraction, the electrochemical lithium recovery (ELR) system was studied in recent years. However, there are a limited number of studies regarding the system behavior and most of them are focused on a batch operation, which is far from practical usage. In this study, a flow-type rocking-chair ELR system based on the λ-MnO2/LiMn2O4 electrode pair is proposed for efficient recovery of lithium ions from influents. A lab-scale electrochemical experiment and a two-dimensional numerical simulation are performed to comprehensively analyze the system behavior. It is confirmed that lithium can be simultaneously captured and released at each electrode without any extra electrode regeneration steps. Apart from identifying its behavior experimentally, the spatiotemporal concentration distribution of Li+ in the separator channel is analyzed through numerical simulation. In our system, Li+ is found to be successfully recovered from the source with an energy consumption of 0.56 Wh mol-1 at 6.25 × 10-2 mA cm-2.