Ultra-fast and stable extraction of Li metal from seawater

One Stone, Two Birds: In Situ Formed Single-Ion Conductor To Enhance Water Stability of Lithium Garnet and Uniformity of Lithium Deposition during Electrolytic Lithium Extraction

With the rising demand for lithium metal, the electrochemical lithium extraction method utilizing solid oxide electrolytes has garnered significant attention. However, due to the inevitable Li+/H+ exchange between the solid electrolyte and water, the lithium extraction rate is constrained by the electrochemical performance of the solid electrolyte. Furthermore, for the potential direct application of the extracted lithium in lithium metal batteries, the uniformity of the extracted anode material is crucial. To this end, a surface modification method utilizing poly(acrylamide-2-methyl-1-propane-sulfonate) (PAMPS) and PAMPSLi is implemented on a typical solid electrolyte selective membrane, Li6.5La3Zr1.5Ta0.5O12 (LLZTO), and polypropylene separator. The in situ formed PAMPSLi coating layer eliminates Li2CO3 from the surface of LLZTO, enhances water stability, and maintains a high ionic conductivity of 0.78 mS cm-1. The modified polypropylene separator enhances the uniformity of deposited lithium by increasing the lithium transference number to 0.66 and forming a stable solid electrolyte interphase (SEI). Consequently, the lithium extraction system can work stably under a current density of 0.10 mA cm-1 for 27 h, and the products can be directly integrated into lithium batteries. This work presents a practical approach to the sustainable utilization of lithium resources and the development of high-performance lithium batteries.

Strong size sieving effect in a rigid oxalate-based metal-organic framework for selective lithium extraction

An oxalate-based metal-organic framework Eu-C2O4 was synthesized at gram-scale and studied as a selective adsorbent for Li+ ions, and it exhibited high Li+/Na+ selectivity in aqueous solution. A detailed mechanism study revealed that the key was the well-matched chelating sites of the framework for Li+ ion extraction.

Vortex-assisted hydrophobic natural deep eutectic solvent liquid-liquid microextraction for the removal of silver ions from environmental water

This study presents a novel approach for the quantification of silver ions in environmental water through the utilization of liquid-liquid microextraction, employing natural deep eutectic solvents in conjunction with inductively coupled plasma emission spectroscopy. The extracted solvent was characterized by Fourier transform infrared spectroscopy (FT-IR). The impact of various extractant types, extractant molar ratio, extractant volume, extraction time, and salt concentration on the efficacy of silver ion extraction was investigated. The findings indicate that the optimal extraction efficiency was attained by utilizing a 5-mL aqueous solution volume, containing 1000 μL thymol/lactic acid NADES 1:3, a salt concentration of 1 mg mL-1, a pH value of 4, and a vortex time of 4 min. Upon implementing the optimized experimental conditions, the recovery of target metal ions was from 96.9 to 101.0%. The relative standard deviations were observed to be within the range of 1.5 to 2.7%. The present study demonstrates the reproducibility, accuracy, and reliability of the method for detecting silver ions in environmental water, with linear range of 5~1000 ng mL-1 and limits of detection (LOD) and limits of quantification (LOQ) of 1.52 ng mL-1 and 5.02 ng mL-1, respectively.

Dual-Channel-Ion Conductor Membrane for Low-Energy Lithium Extraction

The development of energy-efficient and environmentally friendly lithium extraction techniques is essential to meet the growing global demand for lithium-ion batteries. In this work, a dual-channel ion conductor membrane was designed for a concentration-driven lithium-selective ion diffusion process. The membrane was based on a porous lithium-ion conductor, and its pores were modified with an anion-exchange polymer. Thus, the sintered lithium-ion conductors provided highly selective cation transport channels, and the functionalized nanopores with positive charges enabled the complementary permeation of anions to balance the transmembrane charges. As a result, the dual-channel membrane realized an ultrahigh Li+/Na+ selectivity of ∼1389 with a competitive Li+ flux of 21.6 mmol·m-2·h-1 in a diffusion process of the LiCl/NaCl binary solution, which was capable of further maintaining the high selectivity over 7 days of testing. Therefore, this work demonstrates the great potential of the dual-channel membrane design for high-performing lithium extraction from aqueous resources with low energy consumption and minimal environmental impact.

Fluorine-Rich Supramolecular Nano-Container Crosslinked Hydrogel for Lithium Extraction with Super-High Capacity and Extreme Selectivity

Extraction and recovery of lithium from reserves play a critical role in the sustainable development of energy due to the explosive growth of the lithium-battery market. However, the low efficiency of extraction and recovery seriously threatens the sustainability of lithium supply. In this contribution, we fabricate a novel mechanically robust fluorine-rich hydrogel, showing highly efficient Li+ extraction from Li-containing solutions. The hydrogel was facilely fabricated by simple one-pot polymerization of supramolecular nanosheets of fluorinated monomers, acrylic acid and a small amount of chemical crosslinkers. The hydrogel exhibits a remarkable lithium adsorption capacity (Qm Li+ =122.3 mg g-1 ) and can be reused. Moreover, it can exclusively extract lithium ions from multiple co-existing metal ions. Notably, the separation of Li+ /Na+ in actual wastewater is achieved with a surprising separation factor of 153.72. The detailed characterizations as well as calculation showed that the specific coordination of Li-F plays a central role for both of the striking recovery capability and selectivity for Li+ . Furthermore, an artificial device was constructed, displaying high efficiency of extracting lithium in various complex actual lithium-containing wastewater. This work provides a new and promising avenue for the efficient extraction and recovery of lithium resource from complex lithium-containing solutions.

A low-cost anodic catalyst of transition metal oxides for lithium extraction from seawater

Lithium reserves in seawater are tens of thousands of times higher than on land, making it a promising candidate for lithium resources. A lithium extraction method based on a solar-powered electrolysis technique with a solid-state electrolyte, Li1.5Al0.5Ge1.5(PO4)3 (LAGP), as the selective membrane has been reported to obtain metallic lithium from seawater. Herein, the electrolytic cell is optimised by replacing the anode catalyst materials. The NiO@SP anode shows excellent electrochemical performance, relatively high energy utilization efficiency and low cost among the anode materials investigated. An electrolytic cell adopting NiO@SP achieves a lithium production efficiency of 57.2 mg W h-1 with a potential of 4.5 V at a current density of 333 μA cm-2. Based on the investigation by in situ mass spectroscopy the oxygen evolution reaction (OER) and chlorine evolution reaction (CER) occur together on the anode with the production of oxygen and hypochlorite.