Lithium-containing Solutions Research Articles

The Technologies of Electrochemical Lithium Extraction Process from Lithium-Containing Solutions

The Technologies of Electrochemical Lithium Extraction Process from Lithium-Containing Solutions

Hierarchical pore-enhanced ion transport and defect-induced dual strong interactions for highly efficient lithium extraction

In the past decade, adsorption method has attracted great attention on the lithium extraction. The key issue in adsorption technology is to develop adsorbents with high adsorption capacity, selectivity, and recycle-stability. Here, the highly efficient metal–organic framework adsorbents were developed for lithium extraction, which were fabricated by the in-situ conversion of MIL-121 in alkali solution. The adsorbent after acid activation, termed as H-CAOMIL, was featured with the hierarchical porosity, enhanced density of free carboxylic groups, and exposed aluminum-oxygen defect sites to enhance the ion transport and provide dual strong interaction for Li+. H-CAOMIL exhibited the remarkable Li+ adsorption capacity (QLi+ = 5.28 mg/g) and selectivity (αKLi = 21.33, αNaLi= 9) from low-concentration lithium-containing solutions. Moreover, the H-CAOMIL can be easily regenerated in weakly acidic solution. Impressively, Li+ adsorption capacity retained at 92 % of the initial capacity even after five adsorption–desorption cycles. Furthermore, the comprehensive characterizations and theoretical calculations indicated that the specific coordination of COO-Li and AlO-Li played a crucial role in the recovery capacity and selectivity of Li+. This work offers precious insights for the future exploration of highly efficient adsorbents for lithium extraction.

High-temperature anodization route to nanoporous niobium oxides with enhanced supercapacitive properties in aqueous electrolytes

Relatively little work has been done on Nb2O5 pseudocapacitive behaviors in aqueous solutions. Here, the galvanostatic anodization of niobium in K2HPO4-containing glycerol electrolyte at high temperature is fully explored. The anodically grown films on niobium have ordered nanoporous morphology and are composed of a low-crystalline orthorhombic Nb2O5, which can be directly employed as supercapacitor electrodes without any posttreatment process. To further improve their supercapacitive performances, a facile technique to generate Fe-doped Nb2O5 films is developed, where the as-anodized films are treated by an electrochemical doping in FeCl3 ethylene glycol solution. The Fe-doped Nb2O5 films show a wider potential window and higher capacitance than that of the as-anodized films in aqueous electrolytes. They present a maximum areal capacitance of 168.1 mF cm−2 at 1 mV s−1 and excellent cycling stability with 85.8 % capacitance retention after 10,000 cycles. The charge storage in the Fe-doped Nb2O5 is believed to occur by the incorporation of Li+ ions with concomitant reduction of Nb5+ to Nb4+ in aqueous lithium-containing solutions. Unlike nonaqueous media, Li+ intercalation/deintercalation in aqueous media is a diffusion-controlled process, leading to the comparatively slower pseudocapacitive processes. Nevertheless, in terms of an industrial applicability the Fe-doped Nb2O5 films deserve special attention.

Scaling behavior of cation exchange membrane induced by Ca2+ during the electrodialysis for enriching lithium-containing solutions

Membrane fouling, particularly Ca2+-induced scaling on cation exchange membranes (CEM), hinders the application of electrodialysis in lithium extraction. This study investigated the fouling mechanisms of Ca2+ coexisting with Cl− and SO42− on sulfonated CEM, using CaCl2 and CaSO4 solution as the targeted foulants. The conductivity, pH, turbidity, particle size distribution, chemical composition and morphology of the membrane surface were monitored to verify the evolution of the bulk solution and the membrane during the Ca2+-induced fouling. Online detection of conductivity and pH revealed distinct trends in fouling solutions containing Ca2+-Cl- and Ca2+-SO42-. Noticeable changes in turbidity and particle distribution were observed in the concentrated chamber of the highly saturated Ca2+-SO42- solution, whereas the concentrated chamber of the Ca2+-Cl- solution showed turbidity and particle size distribution similar to the initial values. SEM showed that there are different morphologies of scaling crystals in the two types of solution. These fundamental differences are the root cause of the distinct fouling mechanisms between the Ca2+-Cl- solution and Ca2+-SO42- solution. To further investigate the fouling mechanisms, the electrochemical impedance spectroscopy (EIS) was employed to differentiate the impedance of the electric double layer and diffusion layer, providing insights into the characteristics of the CEM-solution interfaces fouled by different lithium-containing solutions. Additionally, adsorption experiments, quartz crystal microbalance with dissipation (QCM-D) and computational simulations (COMSOL, DFT) were conducted to provide detailed insights into the effects of fouling solutions on the properties of the desalted solution, the probability of crystal precipitation, and particularly the interaction between Ca2+ and the functional sites on the CEM. Finally, the Ca2+-induced scaling mechanism of CEM for enriching the lithium-containing solutions with and without SO42− was proposed, elucidating the synergistic effects of Ca2+-induced crystallization in the bulk solution and Ca2+ adsorption on the CEM surface. The research results could offer theoretical guidance for developing pollution control strategies.

(Invited) Circular Manufacturing of Next-Generation Lithium-ion Battery Cathode Materials with R2R Molten Salt Electrodeposition

For the past few years, Xerion has been developing a roll-to-roll (R2R) molten salt electrodeposition technology (DirectPlateTM) for circular manufacturing of lithium-ion battery cathodes. Cathode materials such as LiCoO2, Li(NixMyCoz)O2, and LixMnyOz are demonstrated with good electrochemical properties. DirectPlateTM cathodes are distinctly different from conventional slurry-cast electrodes combining several notable properties: they are very dense with less than 10% porosity, free of additives (carbon and polymer binder), and their crystal orientation can be accurately controlled, enabling high-rate operation at or beyond state-of-the-art areal capacity loading (3-4 mAh/cm2). As Li+ diffusion primarily occurs through the single crystalline domains aligned vertically to the current collector, DirectPlateTM LiCoO2 cathodes delivers good electrochemical properties in a solid-state cell without the need to infiltrate electrolyte into the cathode. We further demonstrate that end-of-life DirectPlateTM cathodes can be efficiently re-lithiated and repaired with a short molten salt treatment; or they can be upcycled into another cathode material with a completely different composition. Finally, we demonstrate that the DirectPlateTM cathode can be employed as a redox membrane for direct lithium extraction from various lithium-containing solutions. Integrating the collective mineral refinement, electrode fabrication and recycling capabilities into the R2R DirectPlateTM platform enables next-generation circular battery manufacturing with much lower energy and environmental cost.

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.

Highly efficient and selective extraction of Li+ from high sodium lithium containing wastewater using manganese series adsorbent

Lithium is an indispensable key material in the energy field and is now the treasure of the times. With the rapid expansion of the lithium battery sector, lithium resources are in a supply dilemma, not replenishing demand. The resource recovery process of retired lithium batteries usually produces lithium-containing solutions, and there are usually monovalent cations such as Na+ with the same valence state as Li+, resulting in no better method to extract Li+ from such solutions. Therefore, efficient and selective lithium recovery is particularly important. To this end, HMn2O4 (HMO) adsorbents were synthesized to recover lithium from high sodium lithium-containing wastewater. The adsorption capacity of HMO for Li+ can reach 26 mg/g. After several cycles of experiments, the adsorption capacity of the synthesized HMO for Li+ held stable at about 20 mg/g. It is also used to recover lithium from high sodium lithium-containing wastewater and compared with commercial adsorbent materials. The separation coefficient was found to be as high as 371.18 (The highest separation factor of commercial adsorbent materials is only 46.62), with good adsorption selectivity and stability. It provides a synthetically convenient idea for the Li+/Na+ separation problem in water, and the good selectivity and excellent cyclic regeneration properties of manganese-based adsorbent materials provide some theoretical support for commercial applications.

Chemical interaction between PVDF and Li cations during LiCl crystallization in VMCr

Lithium is a highly reactive and flammable alkali metal. Due to its high reactivity it is not found in nature as such but is found in minerals. It has applications in electronics, medicine, optics, etc. The lithium demand is continuously growing, in particular for lithium-ion battery industry for electric vehicles and energy storage systems. LiCl can be obtained in solid form by vacuum membrane crystallization (VMCr) using polypropylene membranes or suitably hydrophobized ceramic membranes. On the contrary, to the knowledge of these authors, PVDF membranes did not allow the formation of the solid phase. In this work, for the first time, experimental evidence is shown documenting the inability of PVDF based-membranes to obtain LiCl crystals and it is shown how this is to be attributed to the chemical interaction between lithium and the polymeric PVDF-based matrix. This paper illustrates how the calculation of the variation of surface energy ΔσS between the virgin membrane and the used one, together with EDX, SEM, FTIR and Raman analyses allowed to demonstrate the modification of the original PVDF-based membrane in contact with a lithium-containing solution.

A technology for producing electrode materials for lithium-ion batteries from Kazakhstan spodumene raw materials

This study aims to develop a technology for producing innovative electrode materials for modern lithium batteries. An efficient technology for post-purifying of technical lithium carbonate to reach the level of battery quality (99.95%) was developed. This technology involves causticiziation of technical lithium carbonate, ultrafiltration and ion-exchange sorption of a lithium hydroxide solution, followed by precipitation of lithium carbonate with ammonium carbonate. Cation-exchange resins of the brands Purolite S930Plus, Purolite S940 and Purolite S950 were studied for sorption purification of lithium-containing solutions from calcium and magnesium impurities. Purolite S940 and Purolite S950 can be recommended as the most effective cation exchangers. The kinetic parameters of calcium and magnesium sorption were determined using a Purolite S940 cation exchanger. The bicarbonation mode was set at room temperature and a pressure of 0.3 atm. The synthesized samples of lithium-iron-phosphate studied by the sol-gel method. The structures of the obtained electrode materials corresponding to the standard profile of lithium-iron-phosphate were investigated by X-ray diffraction. The synthesized electrode materials in the structure of lithium half- and button cells confirmed their good electrochemical properties, stable operation of batteries and a high intercalation reversibility of lithium ions in the samples within the potential range of 2.5–4.3 V. The main research results are innovative cathode and anode materials of a new generation for modern lithium-ion batteries with significantly increased capacity and stability of operation, obtained from lithium precursors – battery grade lithium carbonate based on domestic mineral and technogenic raw materials.

Polyacrylonitrile/Crown Ether Composite Nanofibres With High Efficiency for Adsorbing Li(I): Experiments and Theoretical Calculations

Lithium, as the lightest alkali metal, is widely used in military and new energy applications. With the rapid growth in demand for lithium resources, it has become necessary to improve the effectiveness of extraction thereof. By using chemical grafting and electrospinning techniques, nanofibres containing crown ether were developed for adsorbing Li(I) from the brine in salt lakes, so as to selectively adsorb Li(I) on the premise of retaining specific vacancies of epoxy groups in crown ether. In lithium-containing solution, the adsorbing materials can reach adsorption equilibrium within three hours, and the maximum adsorption capacity is 4.8 mg g−1. The adsorption mechanisms of the adsorbing materials for Li(I) were revealed by combining Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) with density functional theory (DFT) calculation. The results indicated that in crown ether, O in epoxy groups was coordinated with Li(I) to form Li–O and four O atoms in the epoxy groups were used as electron donors. After coordination, two O atoms protruded from the plane and formed a tetrahedral structure with Li(I), realising the specific capture of Li(I). By desorbing fibres that adsorbed Li(I) with 0.5-M HCl, the adsorption capacity only decreased by 10.4% after five cycles, proving ability to regenerate such materials. The nanofibres containing crown ether synthesised by chemical grafting and electrospinning have the potential to be used in extracting lithium resources from the brine in salt lakes.

Preparation of LiOH through BMED process from lithium-containing solutions: Effects of coexisting ions and competition between Na+ and Li+

Bipolar membrane electrodialysis (BMED) is a promising method to produce LiOH from lithium containing solutions. However, the coexisting ions will significantly affect the current efficiency of preparing LiOH. Herein, the influence of the ion's property on the mass transfer behavior of the BMED was investigated, establishing the relations between hydration number and ion's migration as well as water osmosis. Effects of coexisting ions on the lithium migration and current efficiency were studied. The results show that the competition from Na+ and K+ reduced the migration rate of Li+ and increased the energy consumption of producing LiOH, and the coexisting K+ had greater impact compared with Na+. The coexisting SO42− in feed solution generated severer lithium leakage into the acid compartment than Cl− did. In addition, influences of the Na/Li molar ratio in feed solution, current density, and characteristics of cation exchange membrane (CEM) on competitions between Na+ and Li+ were discussed. With increasing the Na/Li molar ratio, lithium concentration in base solution decreased, while the energy consumption increased, owing to the dominant role of Na+ in competitive migration and backward diffusion. Larger ion exchange capacity and lower resistivity of CEMs were beneficial for avoiding negative-transfer and enhancing current efficiency.

Electrochemical lithium recovery system through the simultaneous lithium enrichment via sustainable redox reaction

With the drastic increase in the demand for lithium, electrochemical lithium recovery has gained significant attention as an alternative for lime soda evaporation. Despite its high selectivity and efficiency, the industrial application of electrochemical systems remains limited because of its discontinuous operation and the low lithium concentration in the source water. Hence, this study proposes a redox-mediated system for selective lithium recovery in tandem with the continuous enrichment of the source water via a sustainable redox reaction. In the proposed system, the reversible redox reaction of ferri-/ferrocyanide enables continuous enrichment of the source water, while lithium-selective adsorbent (λ-MnO2) selectively recovers the enriched lithium simultaneously. The redox-mediated lithium recovery system successfully concentrated lithium ions up to 37 mM Li+ in an equimolar mixture of 5 mM Li+ and 5 mM Na+, and up to 0.6 mM Li+ even from extremely dilute lithium-containing solutions (0.1 mM Li+: 9.9 mM Na+). With the introduction of λ-MnO2 as a chemical adsorbent, this system exhibited an exceptional selectivity (selectivity coefficient (αLi-Na) of 57) toward lithium from an equimolar mixture, and high lithium selectivity coefficients (αLi-Na: 804 and αLi-Mg: 387) in a synthetic solution equivalent to the Salar de Atacama brine in Chile. Therefore, this study represents progress towards the industrial application of the lithium recovery process, with potential applications for critical metal recovery in general.

Study of the Possibility of Purifying Lithium Chloride Solution to Remove Impurities by Sorption Method

Possibility of using the ion-exchange method for purification of aqueous lithium-containing solutions to remove soluble chemical impurities was studied. As sorbents served strongly acidic (Tokem-140, Tokem-308/545, KU-2-8), weakly acidic (Tokem-200), mixed phosphorus-containing (Purolite S597), and chelate cation exchangers (Amberlite IRC-748, Purolite S930) of imported and domestic manufacture in the H+ and NH4+ forms. The physical properties of the sorbents were examined. Values of the distribution coefficients of lithium and impurity ions and the static exchange capacity were calculated. It was shown that it is possible to perform group extraction of impurities: ions of alkaline-earth (Ca, Mg) and transition metals (Al, Fe, Cu, Ni, Zn, Ti, Cr, Mn) with a Purolite S597 cation exchanger in the H+ form and Cu and Fe admixtures by chelate sorbents (Amberlite IRC-748 and Purolite S930).

Lithium carbonate recovery from lithium-containing solution by ultrasound assisted precipitation

Lithium carbonate (Li2CO3), one of the most important lithium compounds, is usually prepared from lithium-containing solution. The lithium recovery rate and the purity of Li2CO3 are highly dependent on the lithium concentration. In order to get a high lithium recovery rate, high concentrated lithium-containing solution is required, while the purity of Li2CO3 can be low remaining a significant amount of impurities. Usually, it is not possible to obtain high purity Li2CO3 by single-step precipitation with a relatively high lithium recovery rate especially from a low concentrated lithium-containing solution. In this research, ultrasound is introduced to increase lithium recovery rate and prepare industrial grade Li2CO3. The research found that ultrasound can significantly reduce the polymerization of Li2CO3 crystal particles and promote dissociation of impurity ions. At the same time, ultrasound accelerates the nucleation process of Li2CO3 and boosts lithium recovery rate because of cavitation. The different parameters during the Li2CO3 precipitation process were systematically discussed. Under the optimized conditions, the lithium recovery rate can be increased by 12% with a global lithium recovery rate of 97.4%. Li2CO3 with a purity higher than industrial grade can be obtained by one-step precipitation. It demonstrates a potential pathway for effective lithium recovery from low concentrated lithium-containing solution and preparation of industrial grade Li2CO3.

Superior lithium adsorption and required magnetic separation behavior of iron-doped lithium ion-sieves

The recent research on adsorption-based lithium recovery from lithium-containing solutions has been centred on adsorption capacity and separation of lithium ion-sieves powder from solutions. Herein, an effective iron-doped lithium titanium oxide (Fe-doped Li2TiO3) was synthesized by Fe-doping via solid state reactions followed by acid treatment to form iron-doped lithium ion-sieves (Fe/Ti-x(H)). The resulting solid powder displays both superior adsorption capacity of lithium and high separation efficiency of the adsorbent from the solutions. SEM imaging and BET surface area measurement results showed that at Fe doping levels x≤0.15, Fe-doping led to grain shrinkage as compared to Li2TiO3 and at the same time the BET surface area increased. The Fe/Ti-0.15(H) exhibited saturated magnetization values of 13.76emug−1, allowing effective separation of the material from solid suspensions through the use of a magnet. Consecutive magnetic separation results suggested that the Fe/Ti-0.15(H) powders could be applied at large-scale and continuously removed from LiOH solutions with separation efficiency of 96% or better. Lithium adsorption studies indicated that the equilibrium adsorption capacity of Fe/Ti-0.15(H) in LiOH solutions (1.8gL−1 Li, pH 12) reached 53.3mgg−1 within 24h, which was higher than that of pristine Li2TiO3 (50.5mgg−1) without Fe doping. Competitive adsorption and regeneration results indicated that the Fe/Ti-0.15(H) possessed a high selectivity for Li with facile regeneration. Therefore, it could be expected that the iron-doped lithium ion-sieves have practical applicability potential for large scale lithium extraction and recovery from lithium-bearing solutions.

Influence of pH on distribution coefficients of lithium and impurity elements in sorption

The possibility of purifying lithium-containing solutions to remove chemical impurities by sorption in the batch mode was examined. Sulfonic (KU 2-8, Purolite C100, Resinex KW-8), carboxylic (SG-1, Purolite C104FL, Resinex KW-H), and phosphoric acid (Purolite S957) cation-exchange resins were used as sorbents. The distribution coefficients of lithium and impurity elements (sodium, potassium, magnesium, calcium, iron) at different pH values were determined experimentally. The lithium/impurity separation factors were calculated.

Recovery of rubidium and potassium alums from lithium-bearing minerals

Rubidium was recovered from lithium-containing solution from processing zinnwaldite, (KAl(Fe,Li)(Si3Al)O10F2), concentrate after Li2CO3 crystallization as a mixture of rubidium and potassium alums (RbAl(SO4)2.12H2O and KAl(SO4)2.12H2O). The course of individual reactions aiming at rubidium alum separation from carbonated solutions containing potassium as a main contaminant was studied on synthetic solutions. Before the alum precipitation, the original carbonated solution was converted to sulphate solution. Rubidium recovery efficiency at least 95% was achieved if the amount of the precipitation agent (Al2(SO4)3) ranged between 3.5 and 4.0 multiples of stoichiometric amount related to rubidium concentration in the processed solution. Under such conditions, precipitates obtained contain between 4.10 and 3.62% Rb and from 6.02 to 6.25% K and consist of on average 24% rubidium alum and 75% potassium alum.

Potassium (86Rb+) efflux from the rat submandibular gland under sodium-free conditions in vitro.

1. Fragments of rat submandibular gland were pre-loaded with 86Rb+, an isotopic marker of potassium transport, and rate constants for 86Rb+ efflux were determined during superfusion with a physiological salt solution. 2. In sodium-containing solutions acetylcholine evoked a rapid and immediate increase in efflux rate. After reaching a peak value, the efflux rate initially declined rapidly, but a second, slowly declining phase to the response was also evident. The response could be resolved into Ca2(+)-independent and Ca2(+)-dependent phases. 3. The basal efflux rate was elevated during superfusion with solutions in which sodium had been replaced with either lithium or N-methyl-D-glucammonium (NMDG+). Although lithium had a greater effect, which was absent under calcium-free conditions, addition of calcium to initially calcium-free, lithium-containing solutions did not affect the rate of efflux. 4. In the presence of calcium the response to acetylcholine was augmented during exposure to lithium-containing, sodium-free solutions but, in contrast, slightly inhibited when NMDG+ was used as a sodium substituent. 5. The transient, calcium-independent component of the response to acetylcholine was unaffected by exposure to lithium, whereas the calcium-dependent phase of the response was inhibited. 6. Responsiveness to acetylcholine was reduced during superfusion with a calcium-free, NMDG+-containing solution. The response normally observed when extracellular Ca2+ was subsequently elevated, in the continued presence of acetylcholine, was also inhibited. Sensitivity to acetylcholine was retained, however, when the tissue was initially exposed to a solution containing approximately 20 mumol l-1 Ca2+. The response was smaller than that evoked in sodium-containing solutions. 7. The use of lithium as a sodium substituent presents special problems, possibly related to the effects of this ion on the metabolic cycling of phosphatidylinositol-4,5-bisphosphate metabolites.

Sorption of lithium on an inorganic cation-exchange resin based on hydrated titanium dioxide

1. A synthetic, inorganic cation-exchange resin based on hydrated titanium dioxide selectively sorbs lithium from salt solutions with pH ≧ 12. 2. On prolonged contact (6–8 h) of the sorbent with the lithium-containing solution a desorption effect is observed.

A study of calcium compartments in rat brain cortex thin slices: effects of veratridine, lithium and of a mitochondrial uncoupler.

The efflux kinetics of 45Ca from rat brain cortex thin slices previously equilibrated with it, was studied in a superfusion system. Two first order kinetic components of efflux from the tissue were found: k2 = 0.0667 min-1, that was unchanged by lowering the temperature from 37 degrees C to 15 degrees, and k3 = 0.0167 min-1 at 37 degrees C, that was reduced to 0.0897 min-1 at 15 degrees C. This suggests that k2 represents efflux from the extracellular space, and k3 that from the cellular compartment. Addition of the mitochondrial uncoupler carbonyl cyanide, m-chlorophenylhydrazone (CCCP) (10(-5)M) increased the efflux fractional rate constant of 45Ca by 35%, while no change in efflux was induced by 10 mM caffeine. Veratridine (10(-5)M) drastically reduced 45Ca efflux if superfusion was with physiological salt solution (150 mM sodium present), but not if 50 mM lithium replaced an equivalent amount of sodium in the superfusion fluid. This lithium-containing solution did not affect 45Ca efflux in the absence of veratridine. These results indicate that mitochondria accumulate only a minor fraction of intracellular 45Ca; that 45Ca possibly turns over very rapidly in the endoplasmic reticulum, and that most of 45Ca is present in a different, non-mitochondrial, non endoplasmic reticular compartment, the nature of which can be only conjectured.