New Insights into the Application of Lithium‐Ion Battery Materials: Selective Extraction of Lithium from Brines via a Rocking‐Chair Lithium‐Ion Battery System

Abstract

Lithium extraction from high Mg/Li ratio brine is a key technical problem in the world. Based on the principle of rocking‐chair lithium‐ion batteries, cathode material LiFePO 4 is applied to extract lithium from brine, and a novel lithium‐ion battery system of LiFePO 4 | NaCl solution | anion‐exchange membrane | brine | FePO 4 is constructed. In this method, Li + is selectively absorbed from the brine by FePO 4 (Li + + e + FePO 4 = LiFePO 4 ); meanwhile, Li + is desorbed from LiFePO 4 (LiFePO 4 − e = Li + + FePO 4 ) and enriched efficiently. To treat a raw brine solution, the Mg/Li ratio decreases from the initial 134.4 in the brine to 1.2 in the obtained anolyte and 83% lithium is extracted. For the treatment of an old brine solution, the Mg/Li ratio decreases from the initial 48.4 in the brine to 0.5 and the concentration of lithium in the anolyte is accumulated about six times (from the initial 0.51 g L −1 in the brine to 3.2 g L −1 in the anolyte), with the absorption capacity of about 25 mg (Li) g (LiFePO 4 ) −1 . Additionally, it displays a great perspective on the application in light of its high selectively, good cycling performance, effective lithium enrichment, environmental friendliness, low cost, and avoidance of poisonous organic reagents and harmful acid or oxidant.

Lithium versus Mono/Polyvalent Ion Intercalation: Hybrid Metal Ion Systems for Energy Storage

“…The different intercalation ability of various metal ions to LiFePO 4 has been verified by CV and chronopotentiometry studies in different aqueous electrolytes ,,. It has been established that the metal ions intercalation ability into FePO 4 olivine follows the sequence Li + ≫Na + >K + >Mg 2+ ( ion‐sieve effect ), while their deintercalation ability from LiFePO 4 show a reverse sequence, Li + <Na + <K + <Mg 2+ ,,.…”

“…When brine lakes are used as electrolyte, the hybrid Li/Na battery is capable effectively to separate Li + and Na + from seawater . Because of the limited lithium resources, the hybrid aqueous Li/Na battery represents a green technology for extraction of lithium from brine lakes and salt pans …”

“…The volume difference between NaMPO 4 and LiMPO 4 host matrices (about 10 %) determines their different ability for intercalation or co‐intercalation of other metal ions (different from Na + and Li + , respectively). The small vacant sites in delithiated Li x MPO 4 are expected to be suitable for the smaller Li + ions (0.76 Å) than the bigger monovalent cations ,. In addition, Mg 2+ cannot be inserted into FePO 4 host due to strong Coulomb repulsion, although its smaller dimension (0.72 Å) than Li + ions .…”

Materials for lithium recovery from salt lake brine

“…[65,243]. Although the LiFePO 4 /Ag system can reduce the energy consumption, the use Figure 18 Representation of a LiFePO 4 /FePO 4 pair electrochemical system for lithium extraction [239]; b 3-electrode electrochemical system [236]; and c working principle of the LiFePO 4 /Ag pair electrodes for a complete cycle of the lithium recovery [242].…”

“…intercalation and de-intercalation from an electrode is similar to the Li ? adsorption and desorption from a lithium-ion sieve [239]. Kanoh et al proposed an electrochemical system with electrode pairs of k-MnO 2 /Pt, which is a new approach for lithium extraction from salt lake brine that combines electrochemical and adsorption techniques [235].…”