Rare Metals最新文献

Electrolytic copper foil has gained significant attention as an essential component in lithium-ion batteries (LIBs), printed circuit boards (PCBs), and chip packaging substrates (CPSs) applications. With the advancement of LIBs towards higher energy densities and the increasing density of electronic components on circuits, copper foil is required to have demanding properties, such as extremely thin thickness and extremely high tensile strength. This comprehensive review firstly summarizes recent progress on the fabrication of electrolytic copper foil, and the effects of process parameters, cathode substrate, and additives on the electrodeposition behavior, microstructure, and properties of copper foil are discussed in detail. Then the regulation strategies of mechanical properties of electrolytic copper foil are also summarized, including the formation of nanotwins and texture. Furthermore, the recent advances in novel electrolytic copper foils, such as composite foils and extra-thin copper foils, are also overviewed. Lastly, the remaining challenges and perspectives on the further development of electrolytic copper foils are presented.

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By developing high comprehensive performance ((BH)_max + H_cj), Nd-Fe-B magnets can operate stably in high-temperature applications, greatly expanding the application scenarios of them. Unfortunately, there is a constraint relationship between coercivity (H_cj) and maximum magnetic energy product ((BH)_max), and an increase in H_cj always accompanies a decrease in (BH)_max. Here, the excellent comprehensive magnetic performance of up to 86.54, namely (BH)_max of 42.33 MGOe and H_cj of 44.21 kOe, is unprecedented in the sintered Nd-Fe-B magnets. This magnet is obtained by designing a unique grain structure through micrometallurgical reactions to prepare a matrix with excellent comprehensive performance, and then by stepwise diffusion, the (BH)_max and H_cj of the magnet are simultaneously enhanced. The magnet prepared in this way has a “double-shell core” structure and Tb segregation distribution inside the core. The working temperature of the magnet in this work reached 280 °C, providing a new approach for the development of high-performance Nd-Fe-B magnets.

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CuBi₂O₄ is identified as a promising photocathode in photoelectrochemical (PEC) water splitting systems. However, the PEC performance of CuBi₂O₄ is far from expected due to the limited separation and transport efficiency of photogenerated carriers. To address the above issues, a cost-effective ternary Cu:NiO_X/CuBi₂O₄/CuO composite photocathode was designed. Firstly, a thin Cu:NiO_X film was inserted between CuBi₂O₄ and FTO conducting substrate as a hole-selective layer, which promotes the transmission of photogenerated holes to the FTO substrate effectively. Furthermore, the modification of CuO film on the CuBi₂O₄ electrode not only increases the absorption of sunlight and generates more photogenerated carriers, but also constitutes a heterojunction with CuBi₂O₄, creating a built-in electric field, which facilitates the separation of electrons and holes, and accelerates the electrons transfer to electrode–electrolyte interface. The fabricated Cu:NiO_X/CuBi₂O₄/CuO composite photocathode exhibits a surprisingly high photocurrent density of − 1.51 mA·cm⁻² at 0.4 V versus RHE, which is 2.6 times that of the pristine CuBi₂O₄ photocathode. The improved PEC performance is attributed to the synergy effect of the Cu:NiO_X hole-selective layer and the CuBi₂O₄/CuO heterojunction. Moreover, the combination with the BiVO₄/CoS, an unbiased overall water splitting was achieved, which has a photocurrent of 0.193 mA·cm⁻².

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Serpentine structured Co₃Si₂O₅(OH)₄ is inexpensive, chemically stable, and electrochemically active in oxygen evolution reactions (OER). However, the OER activity of Co₃Si₂O₅(OH)₄ materials is still unfavorable due to the low active sites. Here, Mn²⁺-doped Co₃Si₂O₅(OH)₄ serpentine nanosheets with tuned d-band centers are achieved for efficient oxygen evolution in alkaline and neutral electrolytes. The Co_xMn_3−xSi₂O₅(OH)₄ serpentine nanosheets are synthesized by a simple hydrothermal method. The optimized Co_2.4Mn_0.6Si₂O₅(OH)₄ serpentine nanosheets showed favorable OER overpotentials as well as stable durability in KOH solution and phosphate buffer solution, which were superior to most of the Co-based and Mn-based OER electrocatalysts. The in situ Raman spectroscopy shows that the materials are kept well in the electrochemical OER environments. Further density functional theory shows that the d-band center of Co_xMn_3−xSi₂O₅(OH)₄ serpentine nanosheets is shifted more upward in comparison with pristine Co₃Si₂O₅(OH)₄. The changes in the d-band center increase the adsorption of intermediates, optimize the reaction steps, and lower the energy barriers of the OER. That is the main reason for the OER enhancement Mn²⁺-doped Co₃Si₂O₅(OH)₄. This work gives an efficient strategy to design cheap and stable electrocatalytic materials for OER in a broad pH environment.

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Pyrochlore oxide (Y₂Ru₂O₇) has been identified as a promising catalyst for the oxygen evolution reaction (OER) in advanced green energy strategies. However, its electrochemical inertness necessitates the exploration of an effective strategy to facilitate electronic modulation. This study proposes a surface modification approach involving the integration of defective NiFe (D-NiFe) nanoparticles onto a Y₂Ru₂O₇ (YRO) support (YRO@D-NiFeP/Ru) using a Prussian blue analog (PBA). Numerous cyanide (CN) vacancies are generated through the oxidation treatment of the NiFe PBA grown on the YRO support, yielding a defective PBA precursor (YRO@D-PBA). Subsequent annealing facilitates the transformation to the D-NiFe nanoparticles on the YRO support (YRO@D-NiFeP/Ru), which augments the exposure of Ni³⁺ active sites beneficial for the OER. Moreover, the reduction of Ru cations from YRO results in the exsolution of Ru nanoparticles, which promotes synergistic charge transfer from the nanoparticles to the interior of Y₂Ru₂O₇. Consequently, YRO@D-NiFeP/Ru exhibits a remarkable voltage of 1.49 V at 10 mA·cm⁻² and the lowest Tafel slope of 42.4 mV·dec⁻¹. In addition, a Zn–air battery constructed with YRO@D-NiFeP/Ru exhibits an outstanding power density of 136.2 mW·cm⁻² and high charge–discharge stability, confirming the applicability of YRO@D-NiFeP/Ru in metal-air batteries.

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The immense prospects of two-dimensional (2D) materials in the field of high-performance sensing stem from their unique layered structures and superior properties. Constructing heterostructures and refining sensor architectures are at the forefront of innovative research to enhance sensor performance. This review synthesizes the current literature, discussing the photovoltaic attributes, fabrication methods, analytical techniques and integration strategies pertinent to 2D materials. This comprehensive review of the operating principles of various sensors investigates the recent progress and deployment of these materials within diverse sensing devices, including chemical sensors, biosensors and optical sensors. Conclusively, this review serves as a valuable reference for understanding the applications and progress of 2D materials in high-performance sensors and explores their potential in interdisciplinary research.

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The fabrication of high-quality YBa₂Cu₃O_7−δ (YBCO) nanowires has garnered significant attention in the field of high-temperature superconductivity due to their potential applications in quantum communication, deep space exploration, and various other fields. Cl₂-assisted reactive ion etching (RIE) stands out as a more effective and efficient method for patterning scalable thin films. However, neither RIE nor high-density RIE has achieved superconducting YBCO nanowires with a width smaller than 3 μm. Here, we delve into the factors that limit the line width of Cl₂-assisted inductively coupled plasma reactive ion etching (ICP-RIE) processing and the method to elimiate them. Our approach involves utilizing Cl₂/Ar as etching gas and incorporating a specialized vacuum heating process after etching. Our experimental results demonstrate the successful realization of 10 nm-thick YBCO nanowires with widths as small as 0.15 μm, exhibiting excellent performance in terms of their intrinsic superconducting properties. The mechanism is evidenced by X-ray photoelectron spectroscopy (XPS) analysis in comparison of nanowires with and without heating treatment, in which the residual Cl₂ on the sidewall of nanowires evaporates and oxidizes Cu⁺ back into Cu²⁺ in an unetched state.

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Despite the cost and activity advantages, ruthenium-based oxygen evolution reaction (OER) catalysts face severe stability problems for proton exchange membrane water electrolysis (PEM-WE) due to Ru dissolution. Although tremendous attention has been paid to enhancing the stability and activity under small current density in three electrode systems, there still lacks validation under industrial current density at the device level. Aiming at this issue, we report highly active and durable ruthenium-iridium alloyed oxides (IrRuO_x) as the acidic OER catalyst for PEM-WE with exceptional durability for 1600 h at an industrial current density of 2.0 A·cm⁻². X-ray absorption spectroscopy reveals that the introduction of iridium modulates the electronic structure of Ru and strengthens the local Ru–O bonds in RuO₂, which is crucial for ensuring activity and stability. As a result, in comparison with its RuO₂ counterpart, IrRuO_x works stably against the Ru leaching-induced catalytic layer breakage during the stability test. This work demonstrates the great potential of IrRuO_x as the practical OER catalyst for the application in PEM-WE.

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The enhancement of the intensity of red upconversion (UC) emission has significant implications for biological applications. In KZnF₃:Yb³⁺, Er³⁺ which inherently produces high-purity red emission, the introduction of Fe³⁺ markedly improves the UC intensity by a factor of 13. The mechanism behind the enhanced UC red luminescence is deduced to originate from the Yb³⁺-Fe³⁺ dimer, as determined by first principle calculation and analysis of UC luminescence properties. The thermometry performance, based on splitting peaks of red emission, demonstrated enhanced temperature sensitivity at lower ranges. Exploring the photothermal properties, it was observed that temperature exhibited a linear correlation with pump power under a 980 nm laser, achieving levels up to 48 °C. This temperature range is ideal for applications in mild photothermal therapy (MPTT). This work elucidates the material’s potential in advanced biological applications, merging optical thermometry and photothermics, indicating its multifunctional utility.

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The regulation of martensitic transformation and intrinsic brittleness are critical issues for the application of Ni–Mn–Ga shape memory alloys, and they are closely related to the alloy composition and γ phase. In this study, single and dual-phase Ni_55+xMn₂₅Ga_20−x (x = 0, 2, 4 and 6) alloys were fabricated. The proportion of the γ phase was elevated gradually, and the peak martensitic transformation temperature was enhanced from 350 to 460 °C with an increasing Ni/Ga ratio. The microstructures of the γ phase were further regulated from continuous block to dispersed granular after annealing. The annealed dual-phase alloy with x = 2 exhibited greater yield stress, compressive strength and toughness than the annealed single-phase alloy. It maintained plastic deformation without fracture, even at a strain of 30%. High strain energy and dislocation density were observed in the martensite of the dual-phase alloy, which can be attributed to γ phases and the interface between martensite and γ phases. Furthermore, [001]-oriented martensite variants were obtained during deformation in the dual-phase alloy. They were parallel to the loading direction and conducive to improving the compressive strength. This protocol provides in-depth insight into the influence of the γ phase on the texture evolution and mechanical behavior of martensite during deformation.