Advanced Powder Materials最新文献

Sr₂FeCo_0.2Ni_0.2Mo_0.6O_6-δ (SFCNM) and Sr₂FeNi_0.4Mo_0.6O_6-δ (SFNM) were prepared as the hydrogen electrode materials for solid oxide cells (SOCs) and comparatively investigated by density function theory (DFT) and experiments to demonstrate the benefit of Co addition. The reduced SFCNM (R-SFCNM) and SFNM (R-SFNM) contain exsolved Fe–Co–Ni and Fe–Ni nanoparticles, respectively. DFT indicates that Fe–Co–Ni has optimized combination of the d-band center (descriptor of catalyst activity) and adsorption behavior for H₂O, H₂, H, and OH. The cell with SFCNM hydrogen electrode, La_0.8Sr_0.2Ga_0.8Mg_0.2O_3-δ (LSGM) electrolyte, and La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) oxygen electrode (Cell-SFCNM) demonstrates a higher performance than that with an SFNM hydrogen electrode (Cell-SFNM) at temperatures between 700 and 850 °C in both solid oxide fuel cell (SOFC, 3% H₂O-97% H₂/air) and solid oxide electrolysis cell (SOEC, 20% H₂O-80% H₂/air) modes. At 850 and 700 °C, the peak power density is 1.23 and 0.48 ​W·cm⁻² in SOFC mode, while the current density is 1.25 and 0.37 ​A·cm⁻² at 1.3 V in SOEC mode, respectively. The performance degradation rates at 750 °C are 0.17 ​mV·h⁻¹ in SOFC and 0.15 ​mV·h⁻¹ in SOEC modes within 150 ​h, which are improved by Co doping.

In this study, the structural evolution of SiBCN ceramics during crystallization and its effects on oxidation behavior involving different atomic units or formed phases in amorphous or crystalline SiBCN ceramics were analyzed. The amorphous structure has exceptionally high oxidation activity but presents much better oxidation resistance due to its synchronous oxidation of atomic units and homogeneous composition in the generated oxide layer. However, the oxidation resistance of SiBCN ceramic will degrade during the continual crystallization process, especially for the formation of the nanocapsule-like structure, due to heterogeneous oxidation caused by the phase separation. Besides, the activation energy and rate-controlling mechanism of the atomic units and phases in SiBCN ceramics were obtained. The BNC_x (E_a ​= ​145 ​kJ/mol) and SiC_(2-x) (E_a ​= ​364 ​kJ/mol) atomic units in amorphous SiBCN structure can be oxidized at relatively lower temperatures with much lower activation energy than the corresponding BN(C) (E_a ​= ​209 ​kJ/mol) and SiC (E_a ​= ​533 ​kJ/mol) phases in crystalline structure, and the synchronous oxidation of the SiC_(2-x) and BNC_x units above 750 ​°C changes the oxidation activation energy of BNC_x (E_a ​= ​332 ​kJ/mol) to that similar to SiC_(2-x). The heterogeneous oxide layer formed from the nanocapsule-like structure will decrease the activation energy SiC (E_a ​= ​445 ​kJ/mol) and t-BN (E_a ​= ​198 ​kJ/mol).

Emerging energy technologies, aimed at addressing the challenges of energy scarcity and environmental pollution, have become a focal point for society. However, these actualities present significant challenges for modern energy storage devices. Lithium metal batteries (LMBs) have gained considerable attention due to their high energy density. Nonetheless, their use of liquid electrolytes raises safety concerns, including dendritic growth, electrode corrosion, and electrolyte decomposition. In light of these challenges, solid-state batteries (SSBs) have emerged as a highly promising next-generation energy storage solution by leveraging lithium metal as the anode to achieve improved safety and energy density. Metal organic frameworks (MOFs), characterized by their porous structure, ordered crystal frame, and customizable configuration, have garnered interest as potential materials for enhancing solid-state electrolytes (SSEs) in SSBs. The integration of MOFs into SSEs offers opportunities to enhance the electrochemical performance and optimize the interface between SSEs and electrodes. This is made possible by leveraging the high porosity, functionalized structures, and abundant open metal sites of MOFs. However, the rational design of high-performance MOF-based SSEs for high-energy Li metal SSBs (LMSSBs) remains a significant challenge. In this comprehensive review, we present an overview of recent advancements in MOF-based SSEs for LMSSBs, focusing on strategies for interface optimization and property enhancement. We categorize these SSEs into two main types: MOF-based quasi-solid-state electrolytes and MOF-based all solid-state electrolytes. Within these categories, various subtypes are identified based on the combination mode, additional materials, formation state, preparation method, and interface optimization measures employed. The review also highlights the existing challenges associated with MOF materials in SSBs applications and proposes potential solutions and future development prospects to guide the advancement of MOFs-based SSEs. By providing a comprehensive assessment of the applications of MOFs in LMSSBs, this review aims to offer valuable insights and guidance for the development of MOF-based SSEs, addressing the key issues faced by these materials in SSBs technology.

The quest for lightweight and functional materials poses stringent requirements on mechanical performance of porous materials. However, the contradiction between high strength and elevated porosity of porous materials severely limits their application scenarios in emerging fields. Herein, high-strength multifunctional mullite-based porous ceramic monoliths were fabricated utilizing waste fly ash hollow microspheres (FAHMs) by the protein gelling technique. Owing to their unique shell-pore structure inspired by shell-protected biomaterials, the monoliths with porosity of 54.69%–70.02% exhibited a high compressive strength (32.3–42.9 ​MPa) which was 2–5 times that of mullite-based porous ceramics with similar density reported elsewhere. Moreover, their pore structure and properties could be tuned by regulation of the particle size and content of the FAHMs, and the resultant monoliths demonstrated superior integrated performances for multifunctional applications, such as broadband sound insulation, efficient thermal insulation, and high-temperature fire resistance (>1300 ​°C). On this basis, mullite-based porous ceramic lattices (porosity 68.28%–84.79%) with a hierarchical porous structure were successfully assembled by direct ink writing (DIW), which exhibited significantly higher compressive strength (3.02–10.77 ​MPa) than most other ceramic lattices with comparable densities. This unique shell-pore structure can be extended to other porous materials, and our strategy paves a new way for cost-effective, scalable and green production of multifunctional materials with well-defined microstructure.

Ni₃Al-based alloys are excellent candidates for the structural materials used for turbine engines due to their excellent high-temperature properties. This study aims at laser powder bed fusion and post-hot isostatic pressing (HIP) treatment of Ni₃Al-based IC-221 ​M alloy with a high γ′ volume fraction. The as-built samples exhibits unavoidable solidification cracking and ductility dip cracking, and the laser parameter optimization can reduce the crack density to 1.34 ​mm/mm². Transmission electron microscope (TEM) analysis reveals ultra-fine nanoscale γ′ phases in the as-built samples due to the high cooling rate during rapid solidification. After HIP treatment, a fully dense structure without cracking defects is achieved, which exhibits an equiaxed structure with grain size ∼120–180 ​μm and irregularly shaped γ′ precipitates ∼1–3 ​μm with a prominently high fraction of 86%. The room-temperature tensile test of as-built samples shows a high ultimate tensile strength (σ_UTS) of 1039.7 ​MPa and low fracture elongation of 6.4%. After HIP treatment, a significant improvement in ductility (15.7%) and a slight loss of strength (σ_UTS of 831.7 ​MPa) are obtained by eliminating the crack defects. Both the as-built and HIP samples exhibit retained high σ_UTS values of 589.8 ​MPa and 786.2 ​MPa, respectively, at 900 ​°C. The HIP samples exhibita slight decrease in ductility to ∼12.9%, indicating excellent high-temperature mechanical performance. Moreover, the abnormal increase in strength and decrease in ductility suggest the critical role of a high γ′ fraction in cracking formation. The intrinsic heat treatment during repeating thermal cycles can induce brittleness and trigger cracking initiation in the heat-affected zone with notable deteriorating ductility. The results indicate that the combination of LPBF and HIP can effectively reduce the crack density and enhance the mechanical properties of Ni₃Al-based alloy, making it a promising material for high-temperature applications.

Delivering high areal capacitance (C_A) at high rates is crucial but challenging for flexible supercapacitors. C_A is the product of areal loading mass (M_A) and gravimetric capacitance (C_W). Finding and understanding the balance between M_A and C_W of supercapacitor materials is significant for designing high-C_A electrodes. Herein, we have systematically studied the correlation between M_A and C_W of the nanosheet arrays of NiCo−layered double hydroxide (NiCo−LDH), which were electrodeposited on carbon cloth with different heights to adjust the M_A, accompanied by the interlayer distance regulation to improve the C_W. The optimal C_W performance is achieved at the best charge transfer kinetics for each of M_A series. The NiCo−LDH electrode with the suitable M_A (2.58 ​mg ​cm⁻²) and the relatively high C_W (1918 F ​g⁻¹ ​at 5 ​A ​g⁻¹ and 400 ​F ​g⁻¹ ​at 150 ​A ​g⁻¹) present a high C_A of 4948 ​mF ​cm⁻² ​at 12.9 ​mA ​cm⁻² and a record-high 1032 ​mF ​cm⁻² among LDHs-based flexible electrodes at an ultrahigh current density of 387 ​mA ​cm⁻². The corresponding flexible supercapacitor coupled with activated carbon delivers a high energy density of 0.28 ​mWh cm⁻² ​at an ultrahigh power density of 712 ​mW ​cm⁻², showing great potential applications.

Graphitic carbon nitride nanosheets (CNNs) become the most promising member in the carbon nitride family benefitted from their two-dimensional structural features. Recently, great endeavors have been made in the synthesis and modification of CNNs to improve their photocatalytic properties, and many exciting progresses have been gained. In order to elucidate the fundamentals of CNNs based catalysts and provide the insights into rational design of photocatalysis system, we describe recent progress made in CNNs preparation strategies and their applications in this review. Firstly, the physicochemical properties of CNNs are briefly introduced. Secondly, the synthesis approaches of CNNs are reviewed, including top-down stripping strategies (thermal, gas, liquid, and composite stripping) and bottom-up precursor molecules design strategies (solvothermal, template, and supramolecular self-assembly method). Subsequently, the modification strategies based on CNNs in recent years are discussed, including crystal structure design, doping, surface functionalization, constructing 2D heterojunction, and anchoring single-atom. Then the multifunctional applications of g-C₃N₄ nanosheet based materials in photocatalysis including H₂ evolution, O₂ evolution, overall water splitting, H₂O₂ production, CO₂ reduction, N₂ fixation, pollutant removal, organic synthesis, and sensing are highlighted. Finally, the opportunities and challenges for the development of high-performance CNNs photocatalytic systems are also prospected.

Magnetic domain structure plays an important role in regulating the electromagnetic properties, which dominates the magnetic response behaviors. Herein, unique magnetic vortex domain is firstly obtained in the Ni nanoparticles (NPs) reduced from the Ni-based metal-organic frameworks (MOFs) precursor. Due to both the high symmetry spheres and boundary restriction of graphited carbon shell, confined magnetic vortex structure is generated in the nanoscale Ni core during the annealing process. Meanwhile, MOFs-derived Ni@C assembly powders construct special magnetic flux distribution and electron migration routes. MOFs-derived Ni@C microspheres exhibit outstanding electromagnetic (EM) wave absorption performance. The minimum reflection loss value of Ni@C–V microspheres with vortex domain can reach −54.6 ​dB at only 2.5 ​mm thickness, and the efficient absorption bandwidth up to 5.0 ​GHz at only 2.0 ​mm. Significantly, configuration evolution of magnetic vortex driven by the orientation and reversion of polarity core boosts EM wave energy dissipation. Magnetic coupling effect among neighboring Ni@C microspheres significantly enhances the magnetic reaction intensity. Graphitized carbon matrix and heterojunction Ni–C interfaces further offer the conduction loss and interfacial polarization. As result, MOFs-derived Ni@C–V powders display unique magnetic vortex, electronic migration network, and high-performance EM wave energy dissipation.

The increasingly harsh environment of the nuclear reactors and the insurmountable flaws of in-service materials have created an urgent need for the development of the brand-new alloys. For last decade, the high-entropy alloys (HEAs), a novel composition-design strategy, have received much attention due to their promise for the nuclear fields. The application of the multiscale modelling is to explore the irradiation performance and underlying mechanisms of HEAs. Abundant results and data deepen the understanding of the irradiation response, and accelerate the development of advanced irradiation-resistant HEAs. This review introduces the state-of-art multiscale modelling used for studying the irradiated properties of HEAs. Representative irradiation-induced microstructures and properties, as well as damage, are summarized. By strengthening the application of multiscale modelling, a rational design of high irradiation-resistant HEAs is expected.

Cubic rock salt can lower down or break the rare earth transition barrier through interstitial or vacancy defects owing to its great deformation and rotation flexibility. Here, we demonstrate that oxygen vacancies in SrO are induced by proper oxidization and atmosphere adjustment, resulting in defects with various depths and crystal field distortion. The thermally assisted tunneling from defects to ⁵D₄ state and electronic population decrease on ⁵D₃ state of Tb³⁺ are observed by the deformation of adjacent oxygen octahedral structure. Finally, the as-prepared SrO: 0.01 ​Tb³⁺ phosphors, commercial BaMgAl₁₀O₁₇: Eu²⁺ blue phosphor, and CaAlSiN₃: Eu²⁺ red phosphor are mixed and coated onto 280 ​nm deep-ultraviolet LED chip to assemble white light-emitting LED device. The LEDs show CCT of 3850 ​K, 4136 ​K, and 4741 ​K, with color rendering index of 90.3, 90.8, and 92.1, respectively. These insights will advance the fundamental knowledge of crystal engineering in cubic rock salt, and enable new ways to manipulate energy transfer and electronic transition via defects.