Increasing the stability of LiMn2O4 electrodes under high-current-density conditions via SoC control in an electrochemical lithium recovery system

Abstract

For efficient lithium recovery, the electrochemical lithium recovery (ELR) process that uses LiMn2O4 (LMO) electrodes with selectivity for lithium ions, has been introduced. The electrochemical system is environmentally friendly and allows for the recovery of lithium at a high yield, but the issue of manganese dissolution in LMO electrodes, decreasing their stability, remains to be solved. Herein, we suggest a solution to the existing problem through a rapid lithium recovery method that also enhances the stability of LMO electrodes through the state-of-charge (SoC) control approach. The retained discharge capacity of the system with a high current density (0.4 A/g) remains at 99.2% at 60% SoC after 300 cycles. Compared to the results under full charge/discharge operation (44.2% after 300 cycles), the proposed method demonstrates the state-of-charge (SoC) control adjustments at high current density levels to enhance the recovery rate and stability of the electrode. Additionally, high lithium-ion selectivity with a similar recovery rate is maintained at a high current density under 60% SoC operation compared to 100% SoC in lithium recovery tests. These results indicate that the SoC control strategy can increase the efficiency of ELR by improving the stability of the electrode under high-rate operational conditions. © 2024 Korean Society of Environmental Engineers.