Advanced Powder Materials最新文献

Seawater electrolysis is a sustainable energy conversion technology that generates clean energy by splitting seawater into hydrogen and oxygen. However, the catalysts used in seawater electrolysis often face significant stability challenges because of the high concentration of salt ions and other impurities present in seawater. This review aims to discern the pivotal factors influencing catalyst stability in seawater electrolysis, elucidate the corrosion and electrochemical degradation mechanisms, and delve into the various strategies employed to enhance catalyst stability. These strategies encompass catalyst material selection, surface modification techniques, catalyst support materials, and catalyst design strategies. By gaining deeper insights into the obstacles and innovations concerning catalyst stability in seawater electrolysis, this review strives to expedite progress toward the commercialization and widespread adoption of this technology as a renewable and feasible approach for hydrogen production. Ultimately, the goal is to foster a cleaner and more sustainable future by enabling the efficient and enduring generation of hydrogen from seawater.

3D printing of flexible piezoelectric composites (3D-FPCs) is increasingly attracting the attention due to its unique advantage for customized smart applications. However, current research mainly focuses on the 0–3 piezoelectric composites, in which the piezoelectric ceramics are embedded in polymer matrix in the form of particles. The poor connectivity between particles much reduces the conduction of strain and charge in the composites, seriously limiting its application in actuation. In this work, a continuous lead zirconate titanate (PZT) double-layer ceramic scaffold was prepared by 3D printing and assembled with epoxy resin and interdigital electrodes together to manufacture a multifunctional device. The 3D-FPCs exhibit a free strain of 1830 ​ppm in actuating and are able to actuate a stainless-steel cantilever beam to produce a tip displacement of 5.71 ​mm. Additionally, the devices exhibit a sensitivity of 26.81V/g in sensing applications. Furthermore, 3D-FPCs are demonstrated as actuators for mobile small robots and wearable sensors for sensing joint activities.

The reported electrocaloric (EC) effect in ferroelectrics is poised for application in the next generation of solid-state refrigeration technology, exhibiting substantial developmental potential. This study introduces a novel and efficient EC effect strategy in (1–x)Pb(Lu_1/2Nb_1/2)O₃-xPbTiO₃ (PLN-xPT) ceramics for low electric-field-driven devices. Phase-field simulations provide fundamental insights into thermally induced continuous phase transitions, guiding subsequent experimental investigations. A comprehensive composition/temperature-driven phase evolution diagram is constructed, elucidating the sequential transformation from ferroelectric (FE) to antiferroelectric (AFE) and finally to paraelectric (PE) phases for x=0.10−0.18 components. Direct measurements of EC performance highlight x=0.16 as an outstanding performer, exhibiting remarkable properties, including an adiabatic temperature change (ΔT) of 3.03 ​K, EC strength (ΔT/ΔE) of 0.08 ​K ​cm kV⁻¹, and a temperature span (T_span) of 31 ​°C. The superior EC effect performance is attributed to the temperature-induced FE to AFE transition at low electric fields and diffusion phase transition behavior contributing to the wide T_span. This work provides valuable insights into developing high-performance EC effect across broad temperature ranges through the strategic design of continuous phase transitions, offering a simplified and economical approach for advancing ecofriendly and efficient solid-state cooling technologies.

Tuning the surface properties of catalysts is an effective method for accelerating water electrolysis. Herein, we propose a directional doping and interfacial coupling strategy to design two surface-functionalized Schottky junction catalysts for coordinating the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Directional doping with B/S atoms endows amphiphilic g-C₃N₄ with significant n-/p-type semiconductor properties. Further coupling with Fe₃C modulates the energy band levels of B–C₃N₄ and S–C₃N₄, thus resulting in functionalized Schottky junction catalysts with specific surface-adsorption properties. The space-charge region generated by the dual modulation induces a local “OH⁻- and H⁺-enriched” environment, thus selectively promoting the kinetic behavior of the OER/HER. Impressively, the designed B–C₃N₄@Fe₃C||S–C₃N₄@Fe₃C pair requires only a low voltage of 1.52 ​V to achieve efficient water electrolysis at 10 ​mA ​cm⁻². This work highlights the potential of functionalized Schottky junction catalysts for coordinating redox reactions in water electrolysis, thereby resolving the trade-off between catalytic activity and stability.

CoCrMoW alloys with different nitrogen (N) additions (0, 0.05, 0.1, and 0.2 ​wt%) were prepared via laser powder bed fusion (LPBF). The effects of N content on the microstructure and mechanical properties were investigated. The results indicate that the LPBFed CoCrMoW alloy with 0.1 ​wt% N addition (0.1 ​N alloy) shows the best combination of mechanical properties with a yield strength of ∼983 ​MPa and an elongation of ∼19 ​%. Both the LPBF process and the N addition impose great effects on suppressing the γ to ε martensitic transformation, resulting in a decrease in the width and amount of ε laths/stacking faults. Besides, the N addition promotes the segregation of elements Mo, W, and Si along the cellular sub-grain boundaries (CBs), forming fine and discontinuous precipitates rich in Mo, W and Si along the CBs in the 0.1 ​N alloy, but dense and continuous (Mo,W)₅Si₃ precipitates along the CBs in the 0.2 ​N alloy. The (Mo,W)₅Si₃ precipitates with a tetragonal structure were observed and characterized for the first time in the Co–Cr based alloys. The negative mixing enthalpy between the non-metallic elements N, Si and the metallic elements Mo, W, Cr, and the rapid solidification induced segregation of high melting point elements such as Mo and W along CBs during LPBF process, synergistically contribute to the chemical heterogeneity in the alloys. The pure FCC matrix, the slightly increased segregation of Mo, W, Si elements and fine precipitates along the CBs contribute to the good combination of strength and elongation of the 0.1 ​N alloy. However, though pure FCC phase was present in the 0.2 ​N alloy, the dense and continuous (Mo,W)₅Si₃ precipitates along CBs acted as nucleation sites for cracks, deteriorating the elongation of the alloy. Overall, it is possible to tune the mechanical properties of the LPBFed CoCrMoW alloy by adjusting the local chemical heterogeneity.

The development of high-energy-density Li-ion batteries is hindered by the irreversible capacity loss during the initial charge-discharge process. Therefore, pre-lithiation technology has emerged in the past few decades as a powerful method to supplement the undesired lithium loss, thereby maximizing the energy utilization of LIBs and extending their cycle life. Lithium oxalate (Li₂C₂O₄), with a high lithium content and excellent air stability, has been considered one of the most promising materials for lithium compensation. However, the sluggish electrochemical decomposition kinetics of the material severely hinders its further commercial application. Here, we introduce a recrystallization strategy combined with atomic Ni catalysts to modulate the mass transport and decomposition reaction kinetics. The decomposition potential of Li₂C₂O₄ is significantly decreased from ∼4.90V to ∼4.30V with a high compatibility with the current battery systems. In compared to the bare NCM//Li cell, the Ni/N-rGO and Li₂C₂O₄ composite (Ni-LCO) modified cell releases an extra capacity of ∼11.7 ​%. Moreover, this ratio can be magnified in the NCM//SiO_x full cell, resulting in a 30.4 ​% higher reversible capacity. Overall, this work brings the catalytic paradigm into the pre-lithiation technology, which opens another window for the development of high-energy-density battery systems.

Magnetostrictive Fe–Ga alloys have been demonstrated potentialities for numerous applications, whereas, suffering a tradeoff between large magnetostrictive strain and high sensitivity. Herein, bulk polycrystalline Fe₈₁Ga₁₉ alloys were prepared by laser-beam powder bed fusion (LPBF) and then annealed in magnetic field for manipulating the comprehensive magnetostrictive properties. Results indicate that <001> oriented grains are developed in the LPBF-prepared Fe₈₁Ga₁₉ alloys due to high temperature gradient. After magnetic field annealing (MFA), the magnetic domains within the alloys gradually transformed into well-arranged stripe domains, especially, flat and smooth 90° domains were established in the alloys annealed at 2600 ​Oe. As a result, the induced <001> orientation grains and 90° domains contributed to an improved effective magnetic anisotropy constant (57.053 ​kJ/m³), leading to an enhanced magnetostrictive strain of 92 ​ppm. Moreover, the MFA-treated alloys also displayed enhanced magnetostrictive sensitivity (0.097 ​ppm/Oe) owing to the smooth domain structures and low dislocation densities, demonstrating a fruitful strain-sensitivity synergy. In addition, good magnetostrictive dynamic response and enhanced compressive yield strength were also observed for the prepared alloys. This work demonstrates that LPBF and MFA might be an attractive strategy to resolve the tradeoff between strain and sensitivity, providing a basis for the preparation of high-performance magnetostrictive materials.

Water electrolysis via alkaline hydrogen evolution reaction (HER) is a promising approach for large-scale production of high-purity hydrogen at a low cost, utilizing renewable and clean energy. However, the sluggish kinetics derived from the high energy barrier of water dissociation impedes seriously its practical application. Herein, a series of hybrid Pt nanoclusters/Ru nanowires (Pt/Ru NWs) catalysts are demonstrated to accelerate alkaline HER. And the optimized Pt/Ru NWs (10 ​% wt Pt) exhibits exceptional performance with an ultralow overpotential (24 ​mV at 10 ​mA ​cm⁻²), a small Tafel slope (26.3 ​mV dec⁻¹), and long-term stability, outperforming the benchmark commercial Pt/C-JM-20 ​% wt catalyst. This amazing performance also occurred in the alkaline anion-exchange membrane water electrolysis devices, where it delivered a cell voltage of about 1.9 ​V at 1 ​A ​cm⁻² and an outstanding stability (more than 100 ​h). The calculations have revealed such a superior performance exhibited by Pt/Ru NWs stems from the formed heterointerfaces, which significantly reduce the energy barrier of the decisive rate step of water dissociation via cooperative-action between Pt cluster and Ru substance. This work provides valuable perspectives for designing advanced materials toward alkaline HER and beyond.

The Janus MoSSe and alloy MoS_xSe_(1-x), belonging to the family of two-dimensional (2D) transition metal dichalcogenides (TMDs), have gained significant attention for their potential applications in nanotechnology. The unique asymmetric structure of Janus MoSSe provides intriguing possibilities for tailored applications. The alloy MoS_xSe_(1-x) offers a tunable composition, allowing for the fine-tuning of the properties to meet specific requirements. These materials exhibit remarkable mechanical, electrical, and optical properties, including a tunable band gap, high absorption coefficient, and photoconductivity. The vibrational and magnetic properties also make it a promising candidate for nanoscale sensing and magnetic storage applications. Properties of these materials can be precisely controlled through different approaches such as size-dependent properties, phase engineering, doping, alloying, defect and vacancy engineering, intercalation, morphology, and heterojunction or hybridisation. Various synthesis methods for 2D Janus MoSSe and alloy MoS_xSe_(1-x) are discussed, including hydro/solvothermal, chemical vapour transport, chemical vapour deposition, physical vapour depositio, and other approaches. The review also presents the latest advancements in Janus and alloy MoSSe-based applications, such as chemical and gas sensors, surface-enhanced Raman spectroscopy, field emission, and energy storage. Moreover, the review highlights the challenges and future directions in the research of these materials, including the need for improved synthesis methods, understanding of their stability, and exploration of new applications. Despite the early stages of research, both the MoSSe-based materials have shown significant potential in various fields, and this review provides valuable insights for researchers and engineers interested in exploring its potential.

High-energy density dielectrics for electrostatic capacitors are in urgent demand for advanced electronics and electrical power systems. Poly(vinylidene fluoride) (PVDF) based nanocomposites have attracted remarkable attention by intrinsic high polarization, flexibility, low density, and outstanding processability. However, it is still challenging to achieve significant improvement in energy density due to the common contradictions between electric polarization and breakdown strength. Here, we proposed a novel facile strategy that simultaneously achieves the construction of in-plane oriented BaTiO₃ nanowires and crystallization modulation of PVDF matrix via an in-situ uniaxial stretch process. The polar phase transition and enhanced Young's modulus facilitate the synergetic improvement of electric polarization and voltage endurance capability for PVDF matrix. Additionally, the aligned distribution of nanowires could reduce the contact probability of nanowire tips, thus alleviating electric field concentration and hindering the conductive path. Finally, a record high energy density of 38.3 ​J/cm³ and 40.9 ​J/cm³ are achieved for single layer and optimized sandwich-structured nanocomposite, respectively. This work provides a unique structural design and universal method for dielectric nanocomposites with ultrahigh energy density, which presents a promising prospect of practical application for modern energy storage systems.