Semi-continuous electrochemical extraction of lithium from brine using CF-NMMO/AC asymmetric hybrid capacitors

Compared to traditional extraction of lithium using solar evaporation, the electrochemical extraction is advantageous in many aspects, including elevated efficiency, superior selectivity, and low environmental pollution. In this study, LiNi0.038Mo0.012Mn1.95O4 (LNMMO) with good lattice structure and nano morphology was successfully prepared and confirmed by XRD (X-ray diffraction), SEM-Mapping (scanning electron microscope mapping), SEM (scanning electron microscope), and EDX (Energy-dispersive X-ray spectroscopy) analyses. The pairing of LNMMO with activated carbon (AC) yielded obvious cost-effective and environmentally friendly composite when compared to conventional Noble metals used for battery anodes, such as Ag and Pt. A hybrid supercapacitor was assembled using delithiated LNMMO cathode (NMMO) and AC anode to form NMMO/AC. The cell showed high capacity, high rate performance, and excellent cyclic stability. A continuous flow NMMO/AC hybrid supercapacitor (CF-NMMO/AC) was developed for selective capture of Li+ in aqueous solution by combining NMMO/AC hybrid supercapacitor with self-designed continuous flow control system. The device delivered high Li+ extraction efficiencies reaching 14.4 mg/g per one cycle in simulated brine by consuming only 7.91 W h/mol Li+. The overall process produced 97.2% Li+ in simulated brine at optimized operating conditions. Overall, CF-NMMO/AC system provided higher efficiency, superior selectivity, and moderate energy utilization for Li+ recovery from brine. (c) 2019 Elsevier Ltd. All rights reserved.