Electrochemical Resource Recovery Using Battery Electrode Materials

Demand for lithium is dramatically increasing due to the rapid growth of secondary battery usage. Lithium is mainly produced via evaporation and precipitation from brine lakes, which requires a long period of time for lithium production. Also, this process can only be applied to limited water sources that contain low amounts of certain ions, and several environmental concerns are arising regarding the evaporation and precipitation method.<br/> <br/>Recently developed electrochemical lithium recovery systems, whose operation principle mimics that of lithium-ion batteries, might relieve these concerns. The cathodes (e.g., LiMn₂O₄, LiFePO₄) for lithium-ion batteries have the suitable channel size for selective Li⁺ insertion, which enables selective recovery of lithium from source waters with a wide range of lithium ions (Li⁺) concentrations. However, there had been a lack of understanding of the physicochemical behaviors of the Li⁺-selective electrode in realistic operation conditions. In addition, the stability and cost of the counter electrodes of this system have been serious issues that impede the practical application of this system.<br/> <br/>This talk will cover the physicochemical behavior of the Li⁺ selective electrode during the electrochemical lithium recovery process regarding the Li⁺ concentration in source water and the operation rate will be covered. On the basis of the understanding based on the characterization of the electrodes using X-ray techniques, increasing the density of the electrode/electrolyte interface is suggested as a realistic and general route to enhance the overall lithium recovery performance and is experimentally corroborated in a wide range of operating environments. Also, new electrode designs for the electrochemical lithium recovery system to improve performance and durability are suggested.