The extraction of lithium from salt lakes or seawater has attracted worldwide attention because of the explosive growth of global demand for lithium products. The LiMn 2 O 4 -based electrochemical lithium recovery system is one of the strongest candidates for commercial application due to its high inserted capacity and low energy consumption. However, the surface orientation of LiMn 2 O 4 that facilitates Li diffusion happens to be prone to manganese dissolution making it a great challenge to obtain high lithium inserted capacity and long life simultaneously. Herein, we address this problem by designing a truncated octahedral LiMn 2 O 4 (Tr-oh LMO) in which the dominant (111) facets minimize Mn dissolution while a small portion of (100) facets facilitate the Li diffusion. Thus, this Tr-oh LMO-based electrochemical lithium recovery system shows excellent Li recovery performance with high inserted capacity (20.25 mg g −1 per cycle) in simulated brine. In addition, the dissolution rate of manganese per 30 cycles is only 0.44% and the capacity maintained 85% of the initial after 30 cycles. These promising findings accelerate the practical application of LiMn 2 O 4 in electrochemical lithium recovery.
The global need for bromide ions (Br - ) has driven the research focus to extract them from various liquid ores. Highly efficient and selective adsorbent is still lacking. MOF with large surface area and structural stability are promising candidate for Br - extraction. In this work, we prepared Cu-MOF-74 nanocrystals. Abundant hydroxyl groups on them spontaneously reduced Ag + to Ag 0 nanoparticles, resulting in the fabrication of Ag 0 doped Cu-MOF-74. The crystalline structure retains after the doping of Ag 0 when the mass ratio of silver nitrate to MOF is <0.5. The crystals are distorted or even damaged when the ratio is higher than 1.0 according to XRD and DFT calculation. The adsorption capacity of Ag 3 -Cu-MOF-74 is 232.92 mg g -1 , surpassing the capacities of most previously documented adsorbents. The desorption of Br - and thereafter the recovery of adsorbent could be realized through light driven decomposition of AgBr. This MOF adsorbent shows promising application potential in Br - recovery from various liquid ores.
Extracting lithium from salt lakes is an effective way to relieve the shortage of lithium resources. Electrochemical lithium extraction has attracted wide attention due to its high selectivity , eco-friendliness, and high-efficiency. Functional surface coating is an effective approach to improve the cycling performance, stability, and conductivity of the electroactive materials. In this work, LiMn 2 O 4 (LMO) electrode materials were prepared via sol–gel method with island-like CeO 2 coating (CeLMO) for lithium electrochemical adsorption from simulated brine. CeO 2 is helpful to inhibit the agglomeration of active metal oxides and promote the contact and electron transfer between metal oxides. Based on the results from X-ray diffraction, X-ray photoelectron, and Raman spectroscopy , the fate of lithium intercalation and deintercalation in CeLMO is illuminated. CeLMO-2//Ag electrochemical system can produce 96% pure Li + from Li 2 CO 3 precipitated mother liquor, and the adsorption capacity is 36.52 mg·g −1 . The capacity retention after 30 cycles was 60% at 50 mA·g −1 , and the Mn dissolution loss rate is 0.016%. In summary, island-like oxide coating improves electrochemical lithium adsorption efficiency and is a promising technology for producing battery-grade lithium products.
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