LiNixMn2-xO4 for multicycle electrochemical selective recovery of lithium from lithium-ion battery leachate

Lithium (Li) has been known for possessing excellent electrochemical performance due to its growing use in energy-related applications such as lithium-ion batteries (LIBs). End-of-life LIBs are usually recycled through a leaching process that yields a solution known as LIB leachate that contains lithium and other LIB materials. The electrochemical technique, which generally uses lithium-manganese oxide (LMO) electrodes, is one of the promising techniques for selectively recovering lithium from the LIB leachate. However, the stability perfor-mance of LMO is poor, mainly due to the Jahn-Teller effect of Mn3+ in LMO. In this study, substituting with nickel dopant was used to reduce the manganese content of LMO. Lithium was selectively recovered from actual LIB leachate using lithium nickel manganese oxide (LNMO) and activated carbon (AC) electrodes. The effects of operation time and current on lithium recovery from LIB leachate were studied to determine the optimal operation condition. It was discovered that longer operation time and higher current increased lithium adsorption capacity and energy consumption. Lithium recovery using the obtained optimal operation conditions resulted in a lithium adsorption capacity of 1.58 mmol/g, a lithium purity of 95.22 %, and an energy con-sumption of 2.79 Wh/mol. The effect of nickel doping into LMO on its performance was also investigated over 20 cycles. In a 20-cycle lithium recovery test, LiNi0.5Mn1.5O4 (LNMO-0.5) electrode showed stable lithium recovery performance until the 20th cycle, retaining approximately 97 % of the initial lithium adsorption capacity and increasing energy consumption by approximately 7 % after 20 cycles. Meanwhile, for pristine LMO, after 20 cycles, only about 47 % of the initial lithium adsorption capacity was retained, and the energy consumption was approximately 65 % higher than the initial cycle. Due to the outstanding performance of LNMO, it is expected to be a potential material for long-term selective lithium recovery from leachate in actual lithium-ion battery applications.