Construction of nitrogen-doped carbon cladding LiMn2O4 film electrode with enhanced stability for electrochemically selective extraction of lithium ions

Reducing the dissolution of Mn from LiMn 2 O 4 (LMO) and enhancing the stability of film electrodes are critical and challenging for Li + ions selective extraction via electrochemically switched ion exchange technology. In this work, we prepared a nitrogen-doped carbon cladding LMO (C-N@LMO) by polymerization of polypyrrole and high-temperature annealing in the N 2 gas to achieve the above purpose. The modified C-N@LMO film electrode exhibited lower Mn dissolution and better cyclic stability than the LMO film electrode. The dissolution ratio of Mn from the C-N@LMO film electrode decreased by 42% compared to the LMO film electrode after 10 cycles. The cladding layer not only acted as a protective layer but also functioned as a conductive shell, accelerating the migration rate of Li + ions. The intercalation equilibrium time of the C-N@LMO film electrode reached within an hour during the extraction of Li + ions, which was 33% less compared to the pure LMO film electrode. Meanwhile, the C-N@LMO film electrode retained evident selectivity toward Li + ions, and the separation factor was 118.38 for Li + toward Mg 2+ in simulated brine. Therefore, the C-N@LMO film electrode would be a promising candidate for the recovery of Li + ions from salt lakes.