Rare Metals最新文献

Zinc-based batteries (ZBBs) have garnered significant attention in the field of energy storage and conversion owing to their exceptional advantages, including high energy density, intrinsic environmental benignity, low material cost, as well as enhanced safety characteristics. Nevertheless, several critical challenges persist, predominantly the propensity for dendrite growth, inherent kinetic limitations, deleterious electrode side reactions, and perplexing shuttle effects, which collectively impede the practical implementation and commercial viability of ZBBs. In this context, fibers fabricated via electrospinning technology exhibit remarkable advantages in terms of enhanced specific surface area, improved electrical conductivity, and superior mechanical integrity, while also affording optimized pore structures. These unique features render electrospinning fibers particularly promising for addressing the key issues that limit ZBBs performance, including energy density, charge/discharge rate capabilities, and cycling stability. So, it is very necessary to summarize electrospinning technology application in ZBBs. This paper firstly analyzes the fundamental mechanisms and inherent challenges of ZBBs including zinc-ion, zinc-air, and zinc-halide batteries. Subsequently, the application of electrospinning fiber structures in anodes, cathodes, separators, and electrolytes optimization for ZBBs is summarized. Finally, the prospect of electrospinning technology in ZBBs is envisioned, and existing challenges are presented for its further application.

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The electronic structure of semiconductor materials governs the law of electron motion, which profoundly affects the properties such as conductivity and photoelectric conversion. Photo-responsive single-molecule junction technology provides insights into the electronic structure of photogenerated substances at the molecular scale, enabling the characterization of dynamic processes such as charge separation and energy transfer. These processes involve the unique quantum state known as the “exciton”. The electrical characterization technique based on single molecule break junction facilities direct measurement of the photoelectric response of molecules at nanometer and subnanometer scale. This study reviews recent research progress of exciton effects and the characterization of optoelectronic phenomena. The mechanisms of exciton effects in three key optoelectronic phenomena—photoconductivity, photovoltaics, and photoluminescence—are discussed. Furthermore, advanced spectral characterization techniques applied to the in-situ monitoring of single-molecule optoelectronic devices are highlighted. These include Raman spectroscopy with various enhancements, inelastic electron tunneling spectroscopy, and ultrafast spectroscopy with high resolution.

The Li–Mg–N–H (Mg(NH₂)₂–2LiH) system, as a high-capacity Mg-based metal hydrogen storage material (5.6 wt%), has broad prospects for in vehicle hydrogen storage applications, but it still has high hydrogen ab/desorption barriers. To improve its hydrogen storage performance, a nanohydrogen storage alloy was innovatively combined with Mg(NH₂)₂–2LiH, AB5 type nanohydrogen storage alloy LaNi₅ was prepared by co-precipitation method. Nano LaNi₅ and single-walled carbon nanotubes (SWCNTs) were co-doped into the Mg(NH₂)₂–2LiH system at a ratio of 10 wt% and 2 wt%, significantly enhancing the hydrogen storage performance of Mg(NH₂)₂–2LiH. The initial hydrogen ab/desorption temperatures of the co-doped system decreased from 110/130 °C to 45/85 °C. The release of by-product ammonia is significantly inhibited. 4.73 wt% H₂ can be ab/desorption in 150 min at 180/170 °C. Cycle tests show that the co-doped system can still maintain a hydrogen storage capacity of 4.75 wt% after ten hydrogen release cycles. Mechanism and density functional theory study have shown that during the hydrogen release process, partially hydrogenated LaNi₅ weakens the chemical bonding in Mg(NH₂)₂, promoted the dissociation of hydrogen from the Mg(NH₂)₂–2LiH system, while playing a dual role of "hydrogen overflow" and "hydrogen pump". SWCNTs act as auxiliary agents, helping to refine particle size and increase thermal conductivity. The synergistic effect of the two optimizes the comprehensive hydrogen storage performance of Mg(NH₂)₂–2LiH. This study provides a new research method for improving the comprehensive hydrogen storage performance of Mg-based metal hydrogen storage materials using rare earth element catalysts.

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Single-phase high-entropy carbides (HECs) are emerging as promising electrocatalysts for the hydrogen evolution reaction (HER) due to their widely tunable electronic configurations and the synergistic effects of multimetallic sites. However, their controllable synthesis and mechanistic understanding remain significant challenges due to the thermodynamic immiscibility of the multi-metallic elements within the carbide structure. In this study, we demonstrate the first successful synthesis of single-phase HECs based on Mo and W systems through an innovative high-entropy design strategy. Guided by comprehensive thermodynamic predictions, the single-phase solid solution formation temperatures were determined for the HEC-n (n = 2–9) series of high-entropy carbides. We achieved the configurational-entropy driven formation of HEC nanoparticles containing 4–9 transition metal elements via an ultra-fast joule heating process (i.e., (TiZrHfVNbTaCrWMo)C). Through rapid synthesis and screening, we obtained (VNbCrWMo)C nanoparticles exhibiting the best HER activities and exceptional long-term stability over 168 h due to high-entropy composition design and synthesis strategies, outperforming unary, binary, ternary, quaternary carbides and carbides with more than six metallic elements. Theoretical calculations and X-ray photoelectron spectroscopy analysis reveal that the (VNbCrWMo)C high-entropy carbide achieves enhanced HER activity through multi-metallic synergy, where constituent elements cooperatively redistribute electron density at catalytic sites. This work provides a new pathway for the rational design of advanced metal carbide electrocatalysts, highlighting the potential of high-entropy effects in tailoring material properties for energy conversion applications.

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Aqueous supercapacitors (SCs) exhibit exceptional electrochemical characteristics, including extended cycle stability and high-power density, making them highly promising. Though their practical application and commercialization are hindered by low energy density, we developed a high-performance, self-supporting SC electrode to address this limitation using nickel manganese layered double hydroxide (NiMn-LDH) directly synthesized on activated carbon cloth (ACC). This electrode achieved an extraordinary specific capacitance of 2838.8 F g⁻¹ at a current density of 1 A g⁻¹, with 70.3% retention at 30 A g⁻¹ and 86.1% retention after 6,000 cycles at 15 A g⁻¹, demonstrating its remarkable performance and durability. After being assembled into an asymmetric SCs (ASCs) device with the ACC negative electrode in 2M potassium hydroxide (KOH), a broad operating voltage window of 1.6 V with an energy density of up to 89.7 Wh kg⁻¹ was achieved at a power density of 800.0 W kg⁻¹. Furthermore, the device retained 89.30% of its initial capacitance after 10,000 cycles at 10 A g⁻¹, with a near-perfect Coulombic efficiency close to 100%. The fish-scale-like nanostructure effectively increases the active sites of the electrode to make sufficient full contact with the electrolyte, accelerating the transport of electrons/ions and enhancing its electrochemical performance. These findings emphasize the potential of NiMn-LDH for application in wearable and microscale energy storage devices.

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Wound healing remains a critical challenge in medical treatment, particularly for infected and complex wounds. This study introduces a novel sprayable nanocomposite hydrogel dressing (SA/CaCl₂/CeO₂, SCC) that demonstrates exceptional potential for accelerated wound healing and bacterial infection control. By integrating cerium oxide nanoparticles (CeO₂ NPs) with sodium alginate (SA) and calcium chloride (CaCl₂), we developed a versatile and portable wound healing solution that possesses the ability to scavenge reactive oxygen species (ROS), remarkable biocompatibility, antibacterial properties, and regenerative capabilities. The synthesized SCC hydrogel was comprehensively characterized through advanced microscopic and spectroscopic techniques, revealing a unique nanostructured composition with intrinsic redox capacity. In vitro assessments demonstrated excellent cytocompatibility, hemocompatibility, and potent antibacterial activity against both gram-positive and gram-negative bacteria. In vivo rat wound model experiments further validated the hydrogel’s therapeutic efficacy, showing significantly accelerated wound closure, reduced inflammatory responses, and enhanced tissue regeneration. Key innovations include the hydrothermal synthesis of CeO₂ nanoparticles, a simple spray-induced crosslinking process, and the strategic incorporation of nanoparticles to modulate wound healing mechanisms. The SCC hydrogel exhibited superior performance in promoting granulation tissue formation, collagen deposition, and bacterial elimination, positioning it as a promising candidate for advanced wound management strategies.

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Flexible electronics is gaining prominence in modern technology, particularly in flexible displays, wearable electronics, and biomedical applications. Electrodes, as core components of flexible electronics, demand high conductivity, flexibility, and stretchability. However, traditional rigid conductive materials often generate interfacial slip with elastic substrates due to mismatched Young's modulus, adversely affecting device performance. Room-temperature liquid metals (LMs), with their high conductivity and stretchability, have emerged as ideal materials for stable and reliable flexible electronic devices. This review discusses the physical, chemical, and biocompatibility properties of LMs. Additionally, LM-based fabrication strategies including patterning and sintering for flexible electrodes are outlined. Applications in implantable medical devices, wearable electronics, and flexible energy storage are illustrated. Finally, the primary challenges and future research directions in LMs are identified.

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In this study, a novel Ce-based metal–organic framework (Ce–OFDC) was synthesized via the hydrothermal method. To enhance its photocatalytic antimicrobial properties, polymeric carbon nitride (PCN) was incorporated into the Ce-OFDC matrix, forming a Ce-OFDC/PCN composite material. Antibacterial assays demonstrated that Ce-OFDC/PCN had significant inhibitory effects on both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), achieving inhibition rates of 99.5% and 94.3%, respectively. Notably, the antibacterial performance of Ce-OFDC/PCN was superior to that of Ce-OFDC or PCN alone. Furthermore, photocurrent and electrical impedance scanning measurements demonstrated that the Ce-OFDC/PCN composites showed improved photocurrent response and superior efficiency in separating photogenerated electrons and holes. The photocurrent density of Ce-OFDC/PCN reached 120 μA cm⁻², which was 1.5 times higher than that of PCN (80 μA cm⁻²) and 12 times higher than that of Ce-OFDC (10 μA cm⁻²). Electron paramagnetic resonance analysis indicated that reactive oxygen species played a crucial role in the antimicrobial process, with superoxide radicals (·O₂⁻) and hydroxyl radical (·OH) showing the most prominent influence. We conducted reactive oxygen species (ROS) scavenging experiments to further confirm this view. After adding glutathione (GSH) to remove all ROS, the antibacterial efficiency of Ce-OFDC/PCN decreased by about 40%. Adding D-mannitol to remove ·OH reduced the inhibition rate to 54.7%, and adding superoxide dismutase (SOD) to remove ·O₂⁻ reduced the inhibition rate to 65.4%. The Ce-OFDC/PCN heterostructure increased the separation efficiency of photogenerated electrons and holes, producing increased reactive oxygen species. That, in turn, contributed to the observed superior photocatalytic antibacterial performance. This research significantly advanced the development of metal–organic framework (MOF)-based materials and provided valuable insights into the design of antimicrobial photocatalysts.

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Transition metal oxides (TMOs), thanks to their elevated theoretical capacitance and pseudocapacitive properties, are of particular interest in exploring the advanced supercapacitor electrode materials. The present work reports the rapid laser-assisted synthesis of SiC@Fe₂O_3-x anode materials with engineered oxygen vacancies in seconds, which improve the charge transport, redox activity, and structural stability, thus facilitating a substantial enhancement in electrochemical performance. As a result, the resultant SiC@Fe₂O_3-x nanowires exhibit excellent performances with an areal capacitance of 1082.16 at 5 mA cm⁻², and retain 86.7% capacitance over 10,000 cycles. Furthermore, the assembled asymmetric supercapacitors (ASC), employing SiC@Fe₂O_3-x as the negative electrode and Ni(OH)₂ as the positive electrode, delivers a 1.5 V operating voltage, an energy density of 197 μWh cm⁻², and 80.6% capacitance retention after 14,000 cycles, representing their promise toward the applications in next-generation energy storage materials.

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Linearly polarized photodetectors (PDs), leveraging the inherent structural and material information encoded in light’s polarization state, hold transformative potential for applications ranging from remote sensing to biomedical imaging. Traditional systems that rely on external polarizing elements face challenges in miniaturization and efficiency, driving interest in materials with intrinsic anisotropy. Low-dimensional metal halide perovskites, distinguished by their tunable bandgaps, high carrier mobility, and quantum confinement effects, have emerged as a groundbreaking platform for next-generation polarized PDs. This review comprehensively summarizes the theory, materials, and device engineering of linearly polarized PDs based on low-dimensional perovskites. It aims to elucidate polarization mechanisms across dimensions by establishing a rigorous theoretical foundation for linearly polarized PDs of low-dimensional perovskites. Beyond theoretical insights, the review also highlights cutting-edge fabrication techniques for one-dimensional nanowires and two-dimensional heterostructures, along with performance benchmarks of state-of-the-art devices. By integrating experimental advancements with theoretical insights, this work not only advances the fundamental understanding of polarization mechanisms but also outlines actionable pathways for optimizing device performance, stability, and scalability, which may serve as a critical resource for researchers aiming to harness the full potential of low-dimensional perovskites in polarized optoelectronics.