Membranes with precise Li+/Na+ and Li+/K+ separations are imperative for lithium extraction from brine to address the lithium supply shortage. However, achieving this goal remains a daunting challenge due to the similar valence, chemical properties, and subtle atomic-scale distinctions among these monovalent cations. Herein, inspired by the strict size-sieving effect of biological ion channels, a membrane is presented based on nonporous crystalline materials featuring structurally rigid, dimensionally confined, and long-range ordered ion channels that exclusively permeate naked Li+ but block Na+ and K+. This naked-Li+-sieving behavior not only enables unprecedented Li+/Na+ and Li+/K+ selectivities up to 2707.4 and 5109.8, respectively, even surpassing the state-of-the-art membranes by at least two orders of magnitude, but also demonstrates impressive Li+/Mg2+ and Li+/Ca2+ separation capabilities. Moreover, this bioinspired membrane has to be utilized for creating a one-step lithium extraction strategy from natural brines rich in Na+, K+, and Mg2+ without utilizing chemicals or creating solid waste, and it simultaneously produces hydrogen. This research has proposed a new type of ion-sieving membrane and also provides an envisioning of the design paradigm and development of advanced membranes, ion separation, and lithium extraction.

It was confirmed that the detrimental effect of SO42- on Li+ desorption and readsorption intensified with the increase of the SO42-/Cl- ratio, resulting in application limitations of aluminum-based adsorbent (Li/Al-LDHs) in sulfate-type brines. Based on the interlayer anion exchangeability of Li/Al-LDHs, a one-step interlayer restoration strategy was designed with the assistance of molecular dynamics to rapidly substitute the intercalated SO42- with preferentially desorbed Cl-, aiming to fundamentally address the damage to the cycling performance. The strategy effectiveness was verified by the restored adsorption and desorption capacities in various sulfate-type brines. Furthermore, enhanced lithium extraction processes for sulfate-type brines were established and showed universal applicability for complex brines with different compositions during fixed-bed cycles. By regulating the implementation frequency, the Li+ extraction efficiency was improved, in which the extraction amount per unit time could increase by more than 100% compared with the conventional process.

Spodumene flotation stands as the most commonly used method to concentrate lithium minerals. However, it faces significant challenges related to low collector recoveries and similarity in the surface characteristics of the minerals, which make the effective separation of this valuable mineral difficult. For this reason, numerous researchers have conducted studies to address and confront this problem. In this work, an exhaustive bibliographic search was carried out using keywords and search queries, and the results were structured in three sections according to temporal, methodological, and thematic criteria. The first section covers the period from 1950 to 2004, focusing on experimental tests. The second section covers from 2004 to the present and focuses on flotation tests and measurement analysis. Simultaneously, the third section spans from 2011 to the present and is based on molecular dynamics simulations. Topics covered include spodumene surface properties, the influence of metal ions, pre-treatment techniques, and the use of collectors. Ultimately, molecular dynamics simulations are positioned as a tool that accurately represents experimental phenomena. In this context, specialized software such as Materials Studio or Gromacs prove to be reliable instruments that allow a detailed study of mineral surfaces and other elements to be carried out, which justifies their consideration for future research in this scientific field.

Ion-sieve adsorbents are effective materials in practical applications for extracting liquid lithium. However, it is greatly suppressed in adsorption capacity and selectivity (Li/Mg) under natural near-neutral conditions of seawater or salt lakes, due to the interference of in situ released H+ and Mg2+ impurity. This paper proposes an adsorbent with a microenvironment-modulating function as a solution. The introduction of quaternary ammonium groups into the carrier accelerates the migration of H+, while preventing the diffusion of Mg2+ by electrostatic repulsion. Besides, it can also prestore OH-, effectively consuming the generated hydrogen ions in situ. Based on the rational design, the alkali consumption of the microenvironment-modulating strategy is dramatically reduced to 1/144 of the traditional alkali-adding method. Additionally, adsorption performance is significantly promoted under natural pH conditions, with a maximum 33 times higher separation factor (selectivity) and 4 times higher adsorption capacity than commercial ion-sieve adsorbents. This development indicates the feasibility of using microenvironment modulation for effective lithium extraction and inspires the development of next-generation high-performance adsorbents.

Extracting lithium from seawater has emerged as a disruptive platform to resolve the issue of an ever-growing lithium shortage. However, achieving highly efficient and durable lithium extraction from seawater in an energy-efficient manner is challenging, as imposed by the low concentration of lithium ions (Li+) and high concentration of interfering ions in seawater. Here, we report a facile and universal strategy to develop photothermal \"ion pumps\" (PIPs) that allow achieving energy-efficient, augmented, and durable lithium extraction from seawater under sunlight. The key design of PIPs lies in the function fusion and spatial configuration manipulation of a hydrophilic Li+-trapping nanofibrous core and a hydrophobic photothermal shell for governing gravity-driven water flow and solar-driven water evaporation. Such a synergetic effect allows PIPs to achieve spontaneous, continuous, and augmented Li+ replenishment-diffusion-enrichment, as well as circumvent the impact of concentration polarization and scaling of interfering ions. We demonstrate that our PIPs exhibit dramatic enhancement in Li+ trapping rate and outstanding Li+ separation factor yet have ultralow energy consumption. Moreover, our PIPs deliver ultrastable Li+ trapping performance without scaling even under high-concentration interfering ions for 140 h operation, as opposed to the significant decrease of nearly 55.6% in conventional photothermal configuration. The design concept and material toolkit developed in this work can also find applications in extracting high-value-added resources from seawater and beyond.

Lithium carbonate (Li2CO3) plays a crucial role in advancing state-of-the-art lithium-ion batteries (LIBs) for efficient energy storage. The primary source of lithium is lithium-rich brines, which have complex compositions. Conventional extraction processes from brines involve cumbersome methods that often lead to emissions and/or large volumes of wastewater. To address these environmental challenges, a novel and eco-friendly lithium extraction process under ambient pressure is necessary. In this project, we developed an electrolytic process utilizing a NASICON-type solid-state electrolyte (LATP) to extract lithium chloride from low-purity sources at a temperature of 380 °C. To reduce the melting points of the lithium sources, ZnCl2 was introduced as a fluxing agent. The electrolytic process effectively separated Li+ from other coexisting ions, but resulted in their mixture with Zn2+. Subsequently, purification and carbonation processes were employed to produce high-purity Li2CO3 (98.9 %). We also obtained high-purity Zn(OH)2 (>99.9 %) as a value by-product. Despite the formation of color centers that caused the LATP disk to change from white to black during the electrolytic process, it exhibited sufficient ionic conductivity for successful lithium extraction. Our environmentally friendly approach offers a promising pathway for efficient and sustainable lithium extraction, contributing to the advancement of LIB technology for energy storage applications.

Biological ion channels use the synergistic effects of various strategies to realize highly selective ion sieving. For example, potassium channels use functional groups and angstrom-sized pores to discriminate rival ions and enrich target ions. Inspired by this, we constructed a layered crystal pillared by crown ether that incorporates these strategies to realize high Li+ selectivity. The pillared channels and crown ether have an angstrom-scale size. The crown ether specifically allows the low-barrier transport of Li+ . The channels attract and enrich Li+ ions by up to orders of magnitude. As a result, our material sieves Li+ out of various common ions such as Na+ , K+ , Ca2+ , Mg2+ and Al3+ . Moreover, by spontaneously enriching Li+ ions, it realizes an effective Li+ /Na+ selectivity of 1422 in artificial seawater where the Li+ concentration is merely 25 μM. We expect this work to spark technologies for the extraction of lithium and other dilute metal ions.

In this study, a three-step strategy including electrochemical cathode deposition, self-oxidation, and hydrothermal reaction is applied to prepare the LiMn2 O4 nanosheets on carbon cloth (LMOns@CC) as a binder-free cathode in a hybrid capacitive deionization (CDI) cell for selectively extracting lithium from salt-lake brine. The binder-free LMOns@CC electrodes are constructed from dozens of 2D LiMn2 O4 nanosheets on carbon cloth substrates, resulting in a uniform 2D array of highly ordered nanosheets with hierarchical nanostructure. The charge/discharge process of the LMOns@CC electrode demonstrates that visible redox peaks and high pseudocapacitive contribution rates endow the LMOns@CC cathode with a maximum Li+ ion electrosorption capacity of 4.71 mmol g-1 at 1.2 V. Moreover, the LMOns@CC electrode performs outstanding cycling stability with a high-capacity retention rate of 97.4% and a manganese mass dissolution rate of 0.35% over ten absorption-desorption cycles. The density functional theory (DFT) theoretical calculations verify that the Li+ selectivity of the LMOns@CC electrode is attributed to the greater adsorption energy of Li+ ions than other ions. Finally, the selective extraction performance of Li+ ions in natural Tibet salt lake brine reveals that the LMOns@CC has selectivity ( α Mg 2 + Li + $\\alpha _{{\\mathrm{Mg}}^{2 + }}^{{\\mathrm{Li}}^ + }$ = 7.48) and excellent cycling stability (100 cycles), which would make it a candidate electrode for lithium extraction from salt lakes.

Efficient Mg2+ /Li+ separation is crucial to combating the lithium shortage worldwide, yet current nanofiltration membranes suffer from low efficacy and/or poor scalability, because desirable properties of membranes are entangled and there is a trade-off. This work reports a \"tagged-modification\" approach to tackle the challenge. A mixture of 3-bromo-trimethylpropan-1-aminium bromide (E1 ) and 3-aminopropyltrimethylazanium (E2 ) was designed to modify polyethylenimine - trimesoyl chloride (PEI-TMC) membranes. E1 and E2 reacted with the PEI and TMC, respectively, and thus, the membrane properties (hydrophilicity, pore sizes, charge) were untangled and intensified simultaneously. The permeance (34.3 L m-2  h-1  bar-1 ) and Mg2+ /Li+ selectivity (23.2) of the modified membranes are about 4 times and 2 times higher than the pristine membrane, and they remain stable in a 30-days test. The permeance is the highest among all analogous nanofiltration membranes. The tagged-modification method enables the preparation of large-area membranes and modules that produce high-purity lithium carbonate (Li2 CO3 ) from simulated brine.

Nanofiltration (NF) is a promising and sustainable process to extract Li+ from brine lakes with high Mg2+/Li+ mass ratios. However, a trade-off between Li/Mg selectivity and Li recovery exists at the process scale, and the Li/Mg selectivity of commercially and lab-made NF membranes in a single-pass NF process is insufficient to achieve the industrially required Li purity. To overcome this challenge, we propose a multipass NF process with brine recirculation to achieve high selectivity without sacrificing Li recovery. We experimentally demonstrate that Li/Mg selectivity of a three-pass NF process with a commercial NF membrane can exceed 1000, despite the compromised Li recovery as a result of co-existing cations. Our theoretical analysis further predicts that a four-pass NF process with brine recirculation can simultaneously achieve an ultrahigh Li/Mg selectivity of over 4500 and a Li recovery of over 95%. This proposed process could potentially facilitate efficient NF-based solute-solute separations of all kinds and contribute to the development of novel membrane-based separation technologies.