Lithium-rich manganese-based layered oxides (LR) are promising cathodes for high-energy-density lithium-ion batteries, but their practical application is hindered by severe voltage decay, capacity fading, and interfacial instability caused by oxygen release and sluggish Li⁺ diffusion. Here, we report a rapid surface engineering strategy that integrates Na⁺ doping and spinel phase formation to construct ultra-thin and uniform cathode–electrolyte interphase (CEI) films. Density functional theory calculations reveal that Na⁺ incorporation stabilizes lattice oxygen by forming strong Na-O bonds and reduces the Li⁺ diffusion barrier by 0.22 eV. Experimentally, Na⁺ doping expands the Li layer spacing and generates oxygen vacancies, which further facilitate Li⁺ transport. Consequently, the modified cathode exhibits enhanced interfacial stability and suppressed oxygen evolution, leading to a high discharge capacity of 191 mAh·g-1 with 83.6% retention after 300 cycles at 1C, and 107.8 mAh·g⁻¹ even at 10C. This scalable and cost-effective strategy offers new insights into interfacial design for the commercialization of lithium-rich cathodes.

Lithium-rich manganese-based (LR) cathodes can deliver high capacity through oxygen redox, but irreversible oxygen release often causes structural degradation, voltage decay, and poor cycling stability. Herein, we propose a Fick's law–guided gradient molybdenum (Mo) doping strategy to simultaneously stabilize bulk lattice oxygen and protect surface interfaces. Gradient-distributed Mo forms strong Mo–O bonds that suppress oxygen loss, while high-valent Mo induces an in situ Li₂MoO₄ coating and a partial spinel structure, mitigating electrolyte erosion and facilitating Li⁺ diffusion. The optimized LR@S-Mo cathode delivers a reversible capacity of 195.1 mAh·g⁻¹ with 88.6% retention after 300 cycles at 1C. Theoretical calculations support that Mo doping reduces the Li⁺ diffusion barrier and enhances oxygen stability. This work provides a unified surface-to-bulk modification route for high-energy-density LR cathodes. In this work, a surface-enriched, depth-dependent Mo distribution is constructed based on a diffusion-guided design, accompanied by an in situ Li₂MoO₄/spinel surface layer, which correlates with improved electrochemical stability of lithium-rich Mn-based cathodes.

Mineral grinding often represents a major fraction of total energy costs and coarse pre-concentration can significantly decrease unnecessary processing of barren material. Compressed-air ejection is effective at industrial scale, but suffers from low accuracy at millimeter scale. An opto-magnetic sorting process for coarse pre-concentration of REE-bearing particles before grinding was developed and assessed at labscale. The process combines image-based optical thresholding, water-based wetting of selected particles, magnetite adhesion to wetted surfaces, and magnetic lifting. This process thus couples selective magnetite coating (enabled by localized wetting) and magnetic lifting for particle sorting. The process was run in a reject-oriented mode to facilitate early mass rejection before subsequent comminution. Lab-scale experiments on rauhaugite revealed increasing pre-concentration with decreasing particle size, resulting in a low-grade fraction of 30.4 wt% of the 2–4 mm feed for possible early rejection. The high-grade fraction (57% of the 2–4 mm feed) achieved a TREO concentration of 2.32%, reflecting an enrichment factor of approximately 1.35 compared to the feed (1.71%), consistent with a partial realization of the intrinsic upgrading potential of the ore at this mass yield, as inferred from the TREO distribution of RGB-classified particles. The lab system processed 84 kg/h, corresponding to approximately 1 tonne of feed processed within 12 h. Based on an instantaneous power demand of ∼ 0.8 kW, this corresponds to an energy consumption of ∼ 9.6 kWh/tonne under steady-state conditions. The process also exhibited low water usage (∼5.7 L/tonne feed) and > 99% magnetite recyclability (after 3 runs). Beyond REE beneficiation, the proposed approach shows potential for selective pre-concentration of heterogeneous particulate streams requiring localized actuation.

Thick electrodes greatly enhance lithium extraction capacity. However, with the increase of active substances loading, the traditional thick electrodes are more hydrophobic, severely limiting the utilization of active substances. Hence, a sulfonation process to functionalize thick electrodes was applied to enhance their wettability (~45 mg·cm⁻¹) in brine. Experimental and theoretical results show that the lithium extraction capacity of thick electrodes can be significantly improved by enhancing the electrodes hydrophilicity. At 0.8 V, the S-PVDF electrode's capacity for lithium extraction in simulated brine (41.72 mg·g⁻¹) significantly surpassed the PVDF electrode (35.72 mg·g⁻¹), and it also performed well in actual brine (28.8 mg·g⁻¹). The Mg²⁺/Li⁺ ratio in actual brine dropped from 65 to 0.37, achieving effective magnesia‑lithium separation. This method offers a novel approach to developing high-efficiency lithium extraction thick electrodes.

LiMn₂O₄ (LMO) has emerged as a promising electrode material for the electrochemical extraction of lithium from salt lakes due to its excellent lithium-ion selectivity and structural stability. However, the cyclic use of LMO in Salt Lake brines is often hindered by manganese dissolution and crystal structure collapse, primarily caused by the Jahn-Teller effect. These issues significantly reduce the cycling stability and lithium extraction efficiency of LMO, limiting its practical application. To address this challenge, we developed a molten salt-assisted gradient doping-coating synergistic modification technique aimed at effectively suppressing the Jahn-Teller effect. This approach facilitates the formation of chemically bonded MgO nanolayers on the LMO surface and incorporates Mg²⁺ into the bulk structure, thereby significantly enhancing the material's structural stability. Through a combination of density functional theory (DFT) calculations and experimental validation, the modified composite electrode exhibited superior kinetic performance, high capacity, and remarkable cycling stability. In simulated brine, it maintained a lithium adsorption capacity of 26.21 mg·g⁻¹ after 20 consecutive extraction cycles. Furthermore, in the West Taijinar old brine with a high Mg²⁺/Li⁺ ratio of 65.6, the modified electrode demonstrated a capacity retention rate of 81.8 %, approximately 34 % higher than pristine LMO, and reduced the Mg²⁺/Li⁺ ratio from 65.6 to 0.24. Furthermore, the modified electrode exhibited a manganese dissolution rate of only 0.34 %. These findings indicate that the proposed modification strategy significantly improves the cycling stability and lithium extraction performance of LMO, offering a viable pathway for its large-scale application in Salt Lake environments.

Net-zero carbon targets drive the development of new underground activities such as hydrogen storage and in situ critical mineral recovery, all of which involve geochemical reactions between minerals and fluid/ion transport. Understanding these processes is key to optimizing efficiency and minimizing environmental impacts. However, the fundamental mechanisms of ion transport, mineral dissolution, and secondary precipitation remain poorly understood, particularly at the pore scale. This gap partly arises from the challenges of characterizing samples at such a fine scale, where fluid/ion transport and reactions occur simultaneously. Herein, a core-to-pore-scale experimental approach, combined with time-lapse three-dimensional (3D) imaging, is designed to characterize fluid/ion transport, dissolution, and precipitation processes. We implemented this workflow in an electrokinetic in situ recovery (EK-ISR) system. Time-lapse 3D micro-computed tomography (micro-CT) images were acquired during the experiment to observe dissolution and precipitation dynamics and to measure pore-scale physical parameters. Findings indicate uniform reactive ion transport and mineral dissolution under EK conditions, with over 78% of the target mineral dissolved. Time-lapse images reveal multiple dissolution and precipitation patterns that influence reactive transport processes. Geochemical modeling based on pore-scale parameters demonstrates over 90% correlation with core-scale experimental data. Our workflow demonstrates a promising capability for characterizing reactive transport processes across pore-to-core scales.

In response to the problems of large interfacial diffusion resistance and low lithium extraction efficiency in traditional high-loading film electrodes during lithium extraction from salt lakes by the electrochemical de-intercalation method, this paper presents an interfacial engineering strategy based on the carboxymethyl cellulose lithium (CMC[sbnd]Li) binder. By modulating the structure of the inner Helmholtz plane (IHP) of the electrical double layer and enlarging the effective specific surface area, the migration rate of Li⁺ and the lithium extraction efficiency are remarkably enhanced. In this study, a CMC-Li composite electrode sheet was prepared using Spent LiFePO₄ as the raw material. It was demonstrated that the carboxyl (-COOH) and hydroxyl (-OH) functional groups of CMC-Li can be directionally adsorbed on the electrode surface. This adsorption event reconstructs the IHP-layer structure, reduces the solvation energy barrier of Li⁺, and increases the effective specific surface area of the film electrode. As a result, the contact angle decreased from 130.01° to 55.17°. Furthermore, in the CMC-Li system, the lithium extraction rate in simulated brine increased from 0.33 mg·g⁻¹·min⁻¹ to 0.69 mg·g⁻¹·min⁻¹, while the energy consumption decreased by a factor of 3. In the West Taijinar brine, the lithium extraction capacity reached 23.01 mg·g⁻¹ with a concurrent dramatic reduction in the Mg/Li ratio from 141 to 0.42. These results indicate that the CMC-Li system exhibits excellent lithium extraction performance and high selectivity. Overall, this study proposes a groundbreaking interfacial design concept that achieves both high efficiency and sustainability for lithium extraction from salt lake brines.

Cost-effective and efficient lithium extraction technology is vital to foster the growth of lithium industry. This paper proposed a novel approach for the high value utilization of spent LiFePO₄ (S-LiFePO₄) in the field of lithium extraction from salt lakes was proposed using spent LiFePO₄ (S-LiFePO₄) as raw material. The anode, made from spent LiFePO₄, is prepared via a sintering process, while FePO₄, obtained through chemical oxidation, is used as the cathode. Compared with commercial LiFePO₄, this system not only reduces the cost but also greatly shortens the preparation time of FePO₄ (only about 10min is required). And the electrochemical extraction system had a favorable lithium extraction capacity (29.25 mg/g) from actual brine, reducing the Mg/Li ratio from 61.4 to 0.8. This study not only achieved the low-cost preparation of electrode materials and facilitated the large-scale implementation of this process, but also proposed a high-value comprehensive utilization strategy for lithium-ion batteries recycling.

Separation and purification of valuable ions from water is an area of interest to deal with environmental pollution and energy crisis. Although various materials have been developed for the recovery of ions, they still face some drawbacks, such as low separation efficiency and low ion selectivity. As a class of emerging materials, covalent organic frameworks (COFs) have garnered enormous attention for the extraction and separation of ions from water sources. Compared with polymeric membranes, COFs have higher porosity and crystallinity, higher physical and chemical stability, and better functionality. Moreover, they show high specific surface areas and excellent adsorption capacities. This review discusses the properties, synthesis, fabrication and modification of COF-based materials (e.g., adsorbents and membranes). Different parameters affecting the performance of COF-based materials, including pore size, stability, and hydrophilicity/hydrophobicity are assessed. Moreover, the possible mechanisms for ion extraction and separation using COF-based materials are investigated. Finally, the advances, challenges, and prospects in developing COF-based materials with desirable properties for ions extraction and separation are assessed. This review provides significant insights into developing the next generation of high-performance COF-based adsorbents and membranes for sustainable ion separation and extraction.