Zhongwei Zhao

Critical metals in end-of-life low-melting-point alloys are recovered in one step via all-liquid molten-salt electrochemistry, where dynamic activity regulation and rapid liquid–liquid interfacial kinetics enable deep separation with >99.9% purity.

Adsorption is regarded as a green direct lithium extraction process. However, its practical application is limited by the serious dissolution and difficult recovery of adsorbents, as well as a heavy reliance on an external pH environment. To overcome the limitations, this study develops a novel pseudo-electrochemical intercalation/deintercalation method by constructing a Li2TiO3/H2TiO3 electrode pair for lithium extraction. This method is based on water electrolysis with an applied electric field, which in situ establishes a self-supplying acid/base microenvironment within the electrolytic cell. It enables synchronous and efficient lithium release and capture without external chemical reagents. The adsorbent electrode demonstrates excellent cycling stability, retaining over 95.8% capacity after 10 consecutive cycles, with minimal titanium dissolution (average 0.1%). Furthermore, it achieves a lithium adsorption capacity of 39.75 mg·g–1 with outstanding ion selectivity (Li+/Na+ separation factor of 507.66) in simulated Zabuye salt lake brine. This work provides an efficient, stable, and chemical-free strategy for selective lithium recovery, offering a promising route toward sustainable lithium extraction from salt lake resources.

The efficient separation of tungsten and molybdenum represents a pivotal challenge for the effective, high-value-added utilization and recycling of these strategic metal resources. Developing clean and recyclable separation processes has become a major focus of research, reflecting a growing emphasis on sustainability. This study proposes a method for the efficient and deep separation of molybdenum and tungsten from tungstate-based mixed oxides by leveraging their differential coordination properties with hydrogen peroxide. The composites prepared by mechanical mixing were characterized using techniques such as ICP, SEM, XRD, and Raman spectroscopy. The results demonstrated a significant difference in the dissolution behavior of MoO₃ and WO₃ in hydrogen peroxide, indicating a substantial coordination disparity between MoO₃ and WO₃ toward H₂O₂, which can be effectively exploited for Mo/W separation. Additionally, hydrothermal synthesis was employed to simulate the separation under more realistic conditions. In this study, hydrogen peroxide was selected as an effective reagent for separation, and the influence of multiple variables was systematically evaluated. The results demonstrated that under optimal conditions—specifically at a molar ratio nMo/nW = 40, a temperature of 65 °C, nH₂O₂/nM = 1.25 and a reaction time of 1.5 h—a maximum separation factor of 124 between tungsten and molybdenum was achieved. This process exhibits significant potential for industrial application due to its low consumption of H₂O₂, large separation factor, and cost-effectiveness.

Na₂FePO₄F (NFPF) is a promising cathode material for sodium-ion batteries, yet it is still confronted with a cost–performance trade-off. In this study, a low-cost preparation method of high-performance NFPF cathode materials was proposed via an Al-doping strategy, using commercial FePO₄ without premodification. The effect of the Al content on the crystal structure, sodium-ion diffusion kinetics, and electrochemical performance of NFPF was investigated in detail. X-ray diffraction and Rietveld refinements confirmed the high-purity phase. Na_1.98Fe_0.98Al_0.02PO₄F/C (NFPF-Al0.02) showed an excellent rate capability (57.7 vs 44.5 mAh·g^–1 at 5.0 C) and better cycling stability (93.6% vs 66.7% after 100 cycles at 0.5 C) than the undoped NFPF sample. NFPF-Al0.02 also exhibited an excellent capacity retention of 84.6% after 1000 cycles at 5.0 C. GITT, CV, and EIS results revealed an order-of-magnitude increase in the sodium-ion diffusion coefficient of Al-doped NFPF-Al0.02 compared to that of pristine NFPF. A cost–performance comparison between this work and previous studies was conducted. In summary, this innovative method, which can produce high-performance NFPF cathode materials at low cost, is anticipated to significantly promote the commercialization of NFPF-based sodium-ion batteries.

High-purity lithium metal is extracted from alloy feedstocks with high selectivity and efficiency via a fully liquid electrorefining system.

The selective separation of MoS42- and WO42- using quaternary ammonium salt through solvent extraction or ion exchange methods has been wellestablished in the metallurgical industry. However, the conventional electrostatic adsorption theory falls short in explaining the separation mechanism. Through firstprinciples density functional theory (DFT) calculations and newly self-developed deep potential molecular dynamics (DPMD) simulation method, our work first reveals that the disparity in hydration structures of MoS42- and WO42- plays a crucial role in their selective separation. It is proposed that MoS42- and WO42- anions undergo hydration to form [MoS4(H2O)n]2- and [WO4(H2O)n]2-, respectively, facilitated by hydrogen bond (H-bond) interactions. Emphasis is placed on the discrepancy between MoS42and WO42- in hydration structures by the hydration energy, Hirshfeld charge, evaluation of weak interactions, hydration radius, hydration coordination number, and H-bonds distribution. MoS42- presents a larger first hydration radius and a lower first hydration coordination number due to weaker interactions with H2O, while WO42- is subjected to enhanced hydration shielding, resulting in MoS42- anions being more susceptible to be selectively separated by a quaternary ammonium salt. This insight paves the way for the selective separation of MoS42- and WO42-, further bridging the gap between theory and industry applications.

The determination of cesium ions (Cs⁺) is important for various applications, including resource utilization, environmental monitoring, and human health. Electrochemical sensors, with their inherent advantages, stand out as an ideal choice for Cs⁺ detection. However, electrode materials for Cs⁺ sensors usually face problems such as poor selectivity and complex synthesis. Herein, a method employing nickel hexacyanoferrate (NiHCF) as the electrode material for stripping voltammetry in the determination of Cs⁺ was proposed. Both adsorption and electrochemical intercalation exhibited selectivity. In the presence of interfering ions at a 10 : 1 molar ratio to Cs⁺, Cs⁺ was still preferentially intercalated in NiHCF. However, electrochemical intercalation exhibits superior selectivity for Cs⁺ compared to adsorption. Meanwhile, the effect of adsorption on the detection was minimized by electrochemical intercalation. Based on the standard addition method, Cs⁺ was determined using both adsorption and electrochemical intercalation methods. The error reduced significantly from 32.7% above the theoretical value through adsorption to 9.5% below the theoretical value through electrochemical intercalation. This approach not only enhanced the measurement accuracy but also reduced the costs associated with both measurement and preparation. The study proposed a cost-effective and rapid method for Cs⁺ measurement using Prussian blue analogs.