(545k) Selective Lithium Recovery from Brine Using Li1-XNi0.5Mn1.5O4 /Ag Battery System
In this study, LiNi0.5Mn1.5O4 (LNMO) was investigated for its feasibility as a selective Li+ capturing electrode for electrochemical Li recovery in brine solution. The LNMO is paired with Ag as a chloride capturing counter electrode. LNMO was first oxidized (delithiated) to facilitate its Li preference during capture phase. By applying a negative current, the delithiated Li1-xNi0.5Mn1.5O4 or (NMO) paired with Ag (NMO/Ag) was able to capture Li+ (i.e. discharge mode). The electrochemical system was proved to be stable in aqueous environment. The captured ions were then released by reversal of the polarity of the current (charging) in a separate cell containing a recovery electrolyte solution. The operating conditions were optimized through response surface methodology utilizing the central composite design. The determined optimum conditions were used for the repetitive Li capture-release process. Cycling (discharge-charge) experiments and cyclic voltammetry showed high selectivity and stability of the electrode in the presence of other competing cations (Na+, K+, Ca2+, Mg2+). Overall, the results demonstrate the feasibility of the electrochemical system (NMO/Ag) for high-throughput selective Li+ mining process with low energy requirement.
This research was supported by the National Research Foundation of Korea (NRF) under the Ministry of Science and ICT (No. 2017R1A2B2002109) and the Ministry of Education (No. 22A20130012051(BK21Plus).