Electrochemical behavior of novel electroactive LaTi4Mn3O12/polyaniline composite for Li+-ion recovery from brine with high selectivity

With the increase in worldwide consumption of lithium owing to its use in electronic devices, it is necessary to develop less energy-intensive alternatives for Li production to meet its rapidly growing demand. Electrochemical Li harvesting is a simple approach that can complement existing extraction technologies. However, its effectiveness depends on the design of highly efficient electrodes that can preferentially adsorb Li ions in the presence of abundant interfering cations while exhibiting low energy consumption. Herein, we report the synthesis of delithiated LiLaTi4Mn3O12 (LTMO) as a novel electrode material for the effective recovery of Li+ ions from brine. The introduced LTMO/polyaniline (PANI) composite electrode exhibited excellent Li+-ion selectivity, high water stability, and rapid regeneration. The fast intercalation of Li+ ions was attributable to the presence of highly conductive Mn3+ ions along the A-sites and nanopores with suitable diameters for selective host-guest Li extraction. Under optimal conditions (potential - 0.5 V), PANI/LTMO exhibited a Li adsorption capacity as high as 38.7 mg/g after 60 min and a desorption ratio of 98.5 % when the current was reversed. Moreover, the delithiated electrode exhibited selectivity coefficients of 88.5 and 52.5 for Li+/Na+ and Li+/Mg2+ binary solutions, respectively. The PANI/LTMO electrode exhibited faster Li+-ion intercalation/deintercalation while using a small amount of energy and thus has immense potential for use in high-throughput electrodes for effective lithium extraction from seawater.

Automated summary

With the increasing global consumption of lithium, it is important to develop less energy-intensive alternatives for lithium production. Electrochemical lithium harvesting is a simple approach that can complement existing extraction technologies. In this study, a delithiated LiLaTi4Mn3O12 (LTMO)/polyaniline (PANI) composite electrode was synthesized and demonstrated excellent selectivity for Li+ ions, high water stability, and rapid regeneration. The electrode showed a high Li adsorption capacity, efficient desorption, and selectivity for Li+ over interfering cations. This PANI/LTMO electrode has potential for effective lithium extraction from seawater.