Rare Metals最新文献

LiMn_xFe_1−xPO₄ is a promising cathode candidate due to its high security and the availability of a high 4.1 V operating voltage and high energy density. However, the poor electrochemical kinetics and structural instability currently hinder its broader application. Herein, inspired by the hydrogen-bonded cross-linking and steric hindrance effect between short-chain polymer molecules (polyethylene glycol-400, PEG-400), the pomegranate-type LiMn_0.5Fe_0.5PO₄-0.5@C (P-LMFP@C) cathode materials with 3D ion/electron dual-conductive network structure were constructed through ball mill-assisted spray-drying method. The intermolecular effects of PEG-400 promote the spheroidization and uniform PEG coating of LMFP precursor, which prevents agglomeration during sintering. The 3D ion/electron dual-conductive network structure in P-LMFP@C accelerates the Li⁺ transport kinetics, improving the rate performance and cycling stability. As a result, the designed P-LMFP@C has remarkable electrochemical behavior, boasting excellent capacity retention (98% after 100 cycles at the 1C rate) and rate capability (91 mAh·g⁻¹ at 20C). Such strategy introduces a novel window for designing high-performance olivine cathodes and offers compatibility with a range of energy storage materials for diverse applications.

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With the rapid development of new energy and the high proportion of new energy connected to the grid, energy storage has become the leading technology driving significant adjustments in the global energy landscape. Electrochemical energy storage, as the most popular and promising energy storage method, has received extensive attention. Currently, the most widely used energy storage method is metal-ion secondary batteries, whose performance mainly depends on the cathode material. Prussian blue analogues (PBAs) have a unique open framework structures that allow quick and reversible insertion/extraction of metal ions such as Na⁺, K⁺, Zn²⁺, Li⁺ etc., thus attracting widespread attention. The advantages of simple synthesis process, abundant resources, and low cost also distinguish it from its counterparts. Unfortunately, the crystal water and structural defects in the PBAs lattice that is generated during the synthesis process, as well as the low Na content, significantly affect their electrochemical performance. This paper focuses on PBAs’ synthesis methods, crystal structure, modification strategies, and their potential applications as cathode materials for various metal ion secondary batteries and looks forward to their future development direction.

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Lithium metal, with its exceptionally high theoretical capacity, emerges as the optimal anode choice for high-energy-density rechargeable batteries. Nevertheless, the practical application of lithium metal batteries (LMBs) is constrained by issues such as lithium dendrite growth and low Coulombic efficiency (CE). Herein, a roll-to-roll approach is adopted to prepare meter-scale, lithiophilic Sn-modified Cu mesh (Sn@Cu mesh) as the current collector for long-cycle lithium metal batteries. The two-dimensional (2D) nucleation mechanism on Sn@Cu mesh electrodes promotes a uniform Li flux, facilitating the deposition of Li metal in a large granular morphology. Simultaneously, experimental and computational analyses revealed that the distribution of the electric field in the Cu mesh skeleton induces Li inward growth, thereby generating a uniform, dense composite Li anode. Moreover, the Sn@Cu mesh-Li symmetrical cell demonstrates stable cycling for over 2000 h with an ultra-low 10 mV voltage polarization. In Li||Cu half-cells, the Sn@Cu mesh electrode demonstrates stable cycling for 100 cycles at a high areal capacity of 5 mAh·cm⁻², achieving a CE of 99.2%. This study introduces a simple and large-scale approach for the production of lithiophilic three-dimensional (3D) current collectors, providing more possibilities for the scalable application of Li metal batteries.

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Rechargeable aqueous zinc–iodine (Zn–I₂) batteries are widely regarded as a promising contender for energy-storage devices, due to their intrinsic safety, low cost, and high capacity. However, the severe shuttle effect of polyiodides and the large volume change of I₂ cathode induce severe capacity loss and poor electrochemical reversibility, hindering their commercial applications. Herein, we report that the low-cost gelatinized starch (G-starch) can be used as a bifunctional binder for Zn–I₂ batteries to circumvent the above problems simultaneously. Based on both calculation and experimental data, it is demonstrated that the double-helix structure of G-starch with both α-1,4- and α-1,6-glycosidic bonds can strongly interact with polyiodides to suppress the shuttle effect. Moreover, the G-starch with multiple hydrogen-bonded cross-linking networks exhibits a much-enhanced adhesion ability and can buffer the volume expansion of active materials. In contrast, the traditional carboxymethyl cellulose sodium-based aqueous binder lacks these capabilities. As a result, the G-starch binder enables the aqueous Zn–I₂ battery to achieve a high reversible capacity of 212.4 mAh·g⁻¹ at 0.2 A·g⁻¹ after 1000 cycles and ultralong-cycling life over 48,000 cycles with 135.4 mAh·g⁻¹ and 89.6% capacity retention at 2 A·g⁻¹. This work develops a simple yet efficient strategy to construct high-performance Zn–I₂ batteries.

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China's salt lakes hold significant lithium reserves, yet the development of low-concentration lithium resources from the carbonate brines in Tibet is a pressing matter. Alkyl β-diketones extractants are capable of efficiently extracting lithium from alkaline solutions using an extraction method, but its optimized extraction prerequisite is an extreme alkaline solution with higher pH. This research introduces a process for the effective extraction and separation of lithium and sodium from the carbonate brine of Jieze Caka Salt Lake, utilizing trifluorinated β-biketone HBTA (4,4,4-trifluoro-1-phenyl-1,3-butanedione)–TBP (tributyl phosphate)/kerosene system. A three-stage extraction yielded 98.06% of Li⁺ and 1.69% of Na⁺ from the initial brine with a lower pH of 8.961 and a separation factor (β_Li/Na) of 2948. The simplified process was then implemented using organic direct recycling without regeneration and scrubbing raffinate reflux for a total of 23 cycles, thereby demonstrating the exceptional effectiveness and stability of this system. The resulting lithium-rich stripping solution, with the Li/Na mass ratio amplified by 747 times, underwent further magnesium removal and precipitation using sodium carbonate to yield a high-purity lithium carbonate product of 99.50%. This study offers a novel approach and technology for the efficient separation of lithium ion directly from a partial-neutral carbonate salt lake with a high Na/Li ratio and low lithium concentration.

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Electrolyzing seawater is a promising solution to produce hydrogen, which is hindered by low-efficiency oxygen evolution reaction (OER) and noxious chloride chemistry. Herein, the Fe-Co₂P/CeO₂ heterostructure nanosheet arrays are developed to achieve energy-saving and chlorine-free hydrogen generation by coupling hydrogen evolution reaction (HER) with hydrazine oxidation reaction (HzOR) in seawater. The Fe-Co₂P/CeO₂ realizes current densities of 10 and 400 mA·cm⁻² at 52 and 204 mV for HER. The anode potential is significantly decreased after replacing OER with HzOR. Theoretical calculations display that the electronic structure of Fe-Co₂P can be regulated after coupling CeO₂, which lowers the water dissociation barrier and optimizes hydrogen adsorption-free energy, thus boosting catalytic kinetics. Significantly, the hybrid seawater electrolyzer produces hydrogen at ultralow cell voltages, greatly reducing traditional water electrolysis voltages and avoiding hazardous chlorine chemistry. This study provides an avenue to exploit advanced catalysts for acquiring hydrogen with energy-efficiency and chlorine-free from abundant ocean.

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Developing bifunctional materials with smart discoloration and microwave absorption properties has attracted widespread interest in microwave absorption/shielding, yet it is challenging for reversible discoloration performance in humid (such as forest) and dry (desert) environments. Herein, we combined catalytic chemical vapor deposition (CCVD) technology and a hydrothermal synthesis method to develop a FeSiB@C@NiBr₂ atomic-scale double-shell gradient structure with rich interfaces. These nanosheet arrays favor interface polarization, impedance matching, and dipole polarization of the material, thereby optimizing the microwave absorption performance. The optimal reflection loss (RL) value of FeSiB@C@NiBr₂ reached − 59.6 dB at 9.2 GHz, and the effective absorption bandwidth (EAB) reached 7.0 GHz at a thickness of 2.5 mm. Compared with pure FeSiB (RL_min of − 13.5 dB), the RL_min value of the absorber designed by this method increased by ~ 3 times. The color of NiBr₂ in the outermost nanosheet arrays changes between yellow and green in the case of water molecule harvesting and loss, respectively. This novel FeSiB@C@NiBr₂ composite structure material is expected to provide a promising platform for wave-absorbing and smart discoloring materials.

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The practical application of CaSmAlO₄ microwave dielectric ceramics is limited by its low quality factor (Q×f) value and non-zero temperature coefficient resonant frequency (τ_f) value. In this study, we introduced Mg²⁺–Ti⁴⁺ ionic pairs into CaSmAlO₄, along with an excess of 9% Sm₂O₃. The Mg²⁺–Ti⁴⁺ ionic pairs substituted Al³⁺, and two phases simultaneously coexisted in the ceramics: CaSmAlO₄ and Sm₂O₃. As the doping concentration of Mg²⁺–Ti⁴⁺ ionic pairs increased, the relative permittivity exhibited an upward trend, while the quality factor and resonant frequency temperature coefficient first rose and then descended. Remarkably, 0.09Sm₂O₃–0.91CaSmAl_0.7Mg_0.15–Ti_0.15O₄ sintered at 1450 °C yielded excellent dielectric properties: ε_r = 19.72, Q × f = 72,936 GHz, and τ_f = –0.044 ppm·°C^− 1. The factors influencing the microwave dielectric properties of 0.09Sm₂O₃–0.91CaSmAlO₄ ceramics were further examined by considering the crystal structure, grain size, Lichtenecker logarithmic rule, tolerance factor and packing fraction.

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Herein, a dual near-infrared (NIR)-response AgInS₂ and CuInS₂ co-sensitized ZnO photoelectrode array consisting of two spatial-resolved paper working electrodes (PWE₁ and PWE₂) was established to enable paper-based ratiometric photoelectrochemical (PEC) aptasensing of Di(2-ethylhexyl)phthalate (DEHP) based on triple-helix molecular switch (THMS)-mediated “on–off” switching of co-sensitization effect. Profiting from the co-sensitization of AgInS₂ and CuInS₂ on paper-based ZnO, the dual NIR-response cascade sensitization structure of AgInS₂/CuInS₂/ZnO exhibited a wide light response range and high charge separation efficiency, giving a “switch on” state of co-sensitization effect with markedly high photocurrent response. The “switch off” state of the co-sensitization effect was made by RecJf exonuclease-assisted target recycling-induced conformation change of THMS, which caused the detachment of AgInS₂ quantum dots from the aptasensing interface, leading to a significantly decreased photocurrent signal. Accordingly, the constant I₁ of PWE₁ and varying I₂ of PWE₂ were collected based on the incubation of constant concentration of DEHP on PWE₁ and various concentrations of DEHP on PWE₂. The ultrasensitive detection of DEHP was realized by calculating the ratio of I₂/I₁. This work brought new insights into the establishment of a high-performance paper-based ratiometric PEC aptasensing platform for highly sensitive quantification of DEHP.

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