Driven by the rapid advancement of wind, solar, and electric vehicle technologies, the global copper demand has increased significantly, prompting greater attention to complex and refractory copper-bearing minerals. As a representative example, valleriite is widely distributed in Cu–Ni sulfide ores and regarded as the second-most important copper-bearing phase after chalcopyrite. Structurally, valleriite features a layered crystal lattice composed of alternating hydrophobic sulfide and hydrophilic hydroxide layers, imparting it characteristics intermediate between sulfide and oxide ores. This unique structure, combined with its fine grain size, poor crystallinity, and complex intergrowths, greatly limits the efficiency of conventional beneficiation methods, such as flotation and magnetic separation. This review systematically summarizes the global distribution and physicochemical properties of valleriite and critically assesses beneficiation studies reported over the past seven decades. Furthermore, key factors contributing to poor recovery are identified, and potential strategies for improving the processing of valleriite-bearing ores are proposed.

Rapid industrialization in China has caused significant environmental challenges, particularly heavy metal pollution from mine tailings. Toxic heavy metals such as lead (Pb), cadmium (Cd), and mercury (Hg) are released during the processing of mining wastewater and leaching of mine tailings. Owing to their excellent physicochemical properties, cementitious materials are widely used for the solidification/stabilization of heavy metals, immobilizing heavy metals via two distinct mechanisms. Physically, their favorable characteristics, including high mechanical strength, low porosity, and durable matrix, create effective barriers. Chemically, the alkaline environment facilitates the precipitation of metal hydroxides/carbonates. Conversely, hydration products (calcium silicate hydrate gels and ettringite) contribute to immobilization through adsorption and physical encapsulation. This study systematically investigated the migration mechanisms of heavy metal contaminants in mine tailings; further, it elucidated the multifaceted immobilization pathways of cementitious materials, which involve synergistic adsorption, precipitation, and encapsulation by hydration products combined with homocrystalline substitution. A comprehensive analysis indicated that cementitious materials significantly reduced the mobility and bioavailability of heavy metals. Nonetheless, their long-term stability and potential environmental impact require further investigation. This study aims to provide theoretical support for environmental management and sustainable resource utilization, and to explore the broader application potential of cementitious technology for heavy metal stabilization, thereby establishing a theoretical foundation for future research on heavy metals in low-cement solidified/stabilized tailings.

The detection and characterization of non-metallic inclusions are essential for clean steel production. Recently, imaging analysis combined with high-dimensional data processing of metallic materials using artificial intelligence (AI)-based machine learning (ML) has developed rapidly. This technique has achieved impressive results in the field of inclusion classification in process metallurgy. The present study surveys the ML modeling of inclusion prediction in advanced steels, including the detection, classification, and feature prediction of inclusions in different steel grades. Studies on clean steel with different features based on data and image analysis via ML are summarized. Regarding the data analysis, the inclusion prediction methodology based on ML establishes a connection between the experimental parameters and inclusion characteristics and analyzes the importance of the experimental parameters. Regarding the image analysis, the focus is placed on the classification of different types of inclusions via deep learning, in comparison with data analysis. Finally, further development of inclusion analyses using ML-based methods is recommended. This work paves the way for the application of AI-based methodologies for ultraclean-steel studies from a sustainable metallurgy perspective.

The recovery of precious metals (PMs) from secondary resources is critical for addressing global supply-chain vulnerabilities and sustainable resource utilization. This review systematically examines the transformative potential of metal–organic frameworks (MOFs) as next-generation adsorbents for PM recovery, focusing on their synthesis, functionalization, and multiscale adsorption mechanisms. We critically analyze conventional pyrometallurgical and hydrometallurgical methods and highlight their limitations in terms of selectivity, energy consumption, and secondary pollution. In contrast, MOFs offer tunable porosity, abundant active sites, and tunable surface chemistry, enabling efficient PM capture via synergistic physical and chemical adsorption. Advanced modification techniques, including direct synthesis and post-synthetic modification, are reviewed to propose strategies for enhancing the adsorption kinetics and selectivity for Au, Ag, Pt, and Pd. Key structure–property relationships are established through multiscale characterization and thermodynamic models, revealing the critical roles of hierarchical porosity, soft donor atoms, and framework stability. Industrial challenges, such as aqueous stability and scalability, are addressed via Zr–O bond strengthening, hydrophobic functionalization, and support immobilization. This study consolidates the experimental and theoretical advances in MOF-based PM recovery and provides a roadmap for translating laboratory innovations into practical applications within the circular-economy framework.

The limited high-temperature oxidation resistance of Mg alloys is a key factor restricting their development and application. The addition of some rare earth elements (REs), owing to their unique physical and chemical properties, can significantly enhance the oxidation resistance of Mg alloys. Based on our previous study, we conclude that REs such as Gd, Y, and Ce enhance the oxidation resistance of Mg–RE alloys. This article comprehensively reviews recent research progress on high-temperature oxidation behavior and the potential mechanism in Mg–RE alloys. Based on the thermodynamic and kinetic analyses, the evolution of the complex oxide system formed during the high-temperature oxidation of Mg–RE alloys is first summarized. The diffusion behavior and concentration control mechanisms of REs during the oxidation process and how these mechanisms affect the sustained growth of the oxide film and antioxidant properties were elucidated. Moreover, the different structures of the oxide films were classified, and their properties were discussed. Finally, this paper introduces the applications of commonly used REs in Mg alloys and frontier research on their oxidation mechanisms. Based on the above review, we propose that future research perspectives can be explored in terms of expanding the experimental temperature range for oxidation tests, optimizing the chemical composition by adding trace REs to study their synergistic mechanism, revealing the underlying oxidation mechanism through advanced in situ microscopic characterization methods, and investigating the mechanical properties of oxide films using diverse approaches.

Achieving high energy and power densities is currently a core challenge in the fabrication of energy storage materials. Although numerous high-capacity materials have been developed, conventional planar electrodes cannot achieve high active material loading and efficient ion/electron transport simultaneously. By contrast, three-dimensional (3D) structures have attracted increasing interest because of their capacity to enhance active material utilization, shorten ion and electron transport pathways, reduce interfacial impedance, and provide spatial accommodation for volume expansion. Additive manufacturing (AM) technology effectively fabricates energy-storage materials with 3D structures by accurately constructing complex 3D structures via layer-by-layer deposition. Recent studies have employed AM to construct ordered 3D electrodes that can optimize ion/electron transport, regulate electric field distribution, or improve the electrode–electrolyte interface, thereby contributing to enhanced kinetic performance and cycling stability. This review systematically summarizes the applications of several AM technologies in the fabrication of energy storage materials and analyzes their respective advantages and limitations. Subsequently, the advantages of AM technology in the fabrication of energy storage materials and several major optimization strategies are comprehensively discussed. Finally, the major challenges and potential applications of AM technology in energy storage material optimization are discussed.

Backfill is routinely adopted as a ground support measure for underground mines. However, ground stability enhancement by backfill has received limited research attention. This is likely to be because of the conventional assumption that the fill material exhibits a significantly lower stiffness than the host rocks. Significantly, a recent pioneering work revealed the time-dependent ground stability around a backfilled stope with vertical walls through numerical modeling. In practice, underground stopes typically exhibit a higher or lower degree of inclination. This alters the stress state in peripheral rocks and may induce severe instability and dilution, particularly in stope-hanging walls. Hence, it is imperative to analyze the time-dependent ground stability of inclined backfilled stopes for backfill structure design. Therefore, comprehensive numerical simulations were performed using FLAC3D to address this knowledge deficiency by incorporating a coupled analysis of the backfill consolidation behavior and long-term creep deformation in surrounding rocks. The ground stability was evaluated based on the confinement effectiveness, strength–stress ratio, stress path relative to the yield surface, and time-dependent stress redistribution in the rocks. A parametric study revealed that the inclination angle of the backfilled stope reduced the confinement effectiveness in the host rocks when the wall creep was minor. This exacerbated the rock mass sloughing potential. However, a backfilled stope with a shallower dip angle achieved superior ground stability enhancement when the creep deformation was substantial, by applying a more significant compression on the backfill and effectively mobilizing its passive support performance during consolidation. Additional simulations were conducted to analyze the effects of stope height and width, mine depth, mechanical properties of rocks, backfill compressibility, and filling gap on the time-dependent stress redistribution and stability around the inclined backfilled stope.

This study investigates the performance enhancement of super-sulfated cement (SSC) derived from arsenic-containing bio-oxidation waste (BW) through the incorporation of carbonated recycled concrete fines (CRCF). The findings revealed that the addition of 5wt% CRCF yields optimal performance, with compressive strengths reaching approximately 1.83, 12.59, and 42.81 MPa at 1, 3, and 28 d, respectively. These values represented significant increases of 408.3%, 10.0%, and 14.3% compared to the reference sample. The improvement was attributed to the synergistic effects of ultrafine CRCF particles acting as fillers and nucleation sites, as well as the high reactivity of silica gels, which promoted the formation of additional hydration gels. Microstructural analysis confirmed that CRCF addition refined pore structure, and enhanced the stiffness of C–S–H gels. Furthermore, CRCF served as a net CO₂ sink, sequestering 0.268 kg CO₂ per kilogram of CRCF and thereby reducing the carbon footprint of SSC. In addition, the feasibility of applying CRCF-modified SSC in cemented paste backfill (CPB) is highlighted, given the high cement-related carbon footprint of conventional CPB. When 5wt% CRCF-modified SSC was employed in CPB, its 3-d compressive strength attained over 70% of that of ordinary Portland cement (OPC), while the 28-d strength was comparable to that of OPC. The proposed binder thus provides a sustainable pathway for BW valorization, combining waste utilization, carbon sequestration, and improved engineering performance.

Selective depression of pyrite remains a major bottleneck in copper flotation, particularly when high-pyrite ores are processed and saline water is used. In such environments, conventional approaches using lime and inert grinding media often fail to discriminate effectively between pyrite and valuable copper minerals due to strong copper activation on pyrite surfaces. This study introduced a novel approach using inorganic radicals generated from peroxymonosulfate (PMS) to selectively oxidize and depress pyrite. Flotation tests with synthetic high-pyrite ore blends showed that PMS significantly reduced pyrite recovery while maintaining or improving chalcopyrite flotation. Ethylenediaminetetraacetic acid (EDTA) extraction confirmed selective oxidation of pyrite, and electron paramagnetic resonance (EPR) spectroscopy identified hydroxyl (•OH) and sulfate (SO₄^•− radicals as the dominant reactive species. Iron ions from grinding media and mineral surfaces were identified as key activators of PMS. A major insight was pyrite’s dual role, acting both as a radical scavenger and an activator, which made it highly reactive and susceptible to radical-induced oxidation. This process converted surface copper–sulfur species into copper hydroxides, effectively suppressing pyrite flotation. While previous studies have applied EPR to detect radicals in simplified activator/precursor systems, this study provides the first direct mechanistic evidence of radical-driven selectivity in flotation by detecting inorganic radicals in a complex flotation slurry, thereby demonstrating their persistence under industrially relevant conditions and establishing a foundation for more effective and targeted flotation strategies.

Microwave roasting self-leaching is an innovative method for recovering gold from high-sulfur refractory gold concentrates, without using deadly toxic cyanide reagents. However, the mechanism of gold self-leaching, which relies on lixiviants prepared using volatilized sulfur obtained from roasting, has not been fully elucidated. This study employs the response surface methodology to optimize processing parameters, resulting in an increased gold extraction rate of 96.18%. Analytical factorization and the Tafel curve indicate that CuSO₄ and NH₃·H₂O significantly influence the self-leaching process. Furthermore, X-ray photoelectron spectroscopy (XPS) analysis reveals that S²⁻, S₂²⁻, polysulfides (S_n²⁻), and thiosulfate (S₂O₃²⁻) are involved in the gold leaching reaction, with S²⁻, S₂²⁻, and S_n²⁻ serving as primary ligands for gold complexation. The role of S₂O₃²⁻ in the early stages of the gold-leaching reaction is also noteworthy. The copper–ammonia complex catalyzes the self-leaching gold reaction; however, an improper addition ratio can lead to copper-sulfur compound precipitates, reducing the extraction rate.

Manganese is a major impurity in acidic vanadium-bearing leaching solutions, but its effects on vanadium precipitation via hydrolysis and acidic ammonium salts remain unclear. In this study, vanadium-bearing leachates with varying manganese concentrations (VL-cMn) were prepared through calcium, a calcium–manganese composite, and manganese-based roasting of vanadium slag (VS) to investigate the influence of manganese on vanadium precipitation behavior during hydrolysis precipitation (HP) and ammonium salt precipitation (AP), as well as the microscopic characteristics and purity of the resulting V₂O₅ products. The results showed that increasing the pH mitigated the negative effects of Mn on the V precipitation rate during HP. However, as the manganese concentration increased from 5.69 to 15.38 g/L, the V precipitation rate gradually declined at higher temperatures and longer reaction times. The precipitates exhibited increased microstructural density, which might had contributed to the formation of Mn-bearing phases. Additionally, the average grain size of V₂O₅ was reduced and the particles were increasingly agglomerated, leading to a 2.55% decrease in product purity. For AP, as manganese concentration increased, raising the pH counteracted the negative impact of Mn on the V precipitation rate and reduced the required amount of ammonium sulfate. Moreover, Mn was unevenly adsorbed on the surface of the precipitates. Although V₂O₅ grains gradually shrank and became denser, there was no significant effect on the final product purity, which remained above 99.3%. In conclusion, roasting with added manganese salts influenced the hydrolysis of vanadium but had no significant effect on acidic ammonium salt precipitation.

Desulfurization of CaO–Al₂O₃ particles in molten steel was observed in situ using high-temperature confocal scanning laser microscopy. The effects of the aluminum and silicon contents of molten steel on desulfurization were analyzed. When the total aluminum content in the steel increased from 6 to 1100 ppm, the CaS content in CaO–Al₂O₃ particles increased from 2.1wt% to 84.84wt% after the reaction for 90 s. Furthermore, when the silicon content in the steel increased from 0.01wt% to 2.20wt%, the CaS content in CaO–Al₂O₃ particles increased from 1.53wt% to 79.01wt% after the reaction for 90 s. This indicates that the increase in the aluminum and silicon contents of the steel promoted the desulfurization of CaO–Al₂O₃ particles. A kinetic model was established to predict the CaO–Al₂O₃ particles composition, and the diffusion coefficient of sulfur in CaO–Al₂O₃ particles was 9.375 × 10⁻¹⁰ m²·s⁻¹ at 1600°C, which provided a new method for the calculation of diffusion coefficient.

The viscosity of refining slags plays a critical role in metallurgical processes. However, obtaining accurate viscosity data remains challenging due to the complexities of high-temperature experiments, often relying on empirical models with limited predictive capabilities. This study focuses on the influence of optical basicity on viscosity in CaO–Al₂O₃-based refining slags, leveraging machine learning to address data scarcity and improve prediction accuracy. An automated framework for algorithm integration, parameter tuning, and evaluation ranking framework (Auto-APE) is employed to develop customized data-driven models for various slag systems, including CaO–Al₂O₃–SiO₂, CaO–Al₂O₃–CaF₂, CaO–Al₂O₃–SiO₂–MgO, and CaO–Al₂O₃–SiO₂–MgO–CaF₂. By incorporating optical basicity as a key feature, the models achieve an average validation error of 8.0% to 15.1%, significantly outperforming traditional empirical models. Additionally, symbolic regression is introduced to rapidly construct domain-specific features, such as optical basicity-like descriptors, offering a potential breakthrough in performance prediction for small datasets. This work highlights the critical role of domain-specific knowledge in understanding and predicting viscosity, providing a robust machine learning-based approach for optimizing refining slag properties.

A full-sectional microstructure characterization method was developed to investigate the formation of coarse slag rims during the continuous casting of hypo-peritectic steel. The cross-sectional microstructural analysis of typical slag rims for two highly crystalline powders revealed that their formation was primarily driven by the solidification of the liquid slag. Distinct differences were observed in the microstructures of slag rims from the two powders. Powder A (characterized by a higher breaking temperature and viscosity) displayed alternating lamellar microstructures of coarse and fine phases, with the coarse phases composed of akermanite–gehlenite transition phases. In contrast, powder B (with a lower breaking temperature and viscosity) predominantly comprised regular akermanite–gehlenite crystals interspersed with a certain amount of glassy phases. Numerical simulations of a three-phase fluid flow coupled with heat transfer indicate that slag rim formation correlates with mold oscillation. Solidification of the liquid slag at the slag rim front predominantly occurs during the negative stroke of the mold oscillation. The average heating rate during the ascending stage of the mold reaches approximately 100 K·s⁻¹, whereas the average cooling rate during the descending stage attains 400 K·s⁻¹. This temperature variation leads to the formation of lamellar microstructures, whereas the ascending stage promotes the formation of coarse structures and thicker slag rims. Based on the powder properties, two distinct formation pathways exist for highly crystalline mold powders. For the powders with a higher breaking temperature, higher viscosity, and narrower solidification range (powder A), coarse microstructures and thicker slag rims were preferentially formed. For powders with lower breaking temperature and viscosity and wider solidification ranges (powder B), the liquid slag resisted rapid solidification, and the extended mushy zone allowed the partial liquid slag to persist at the slag rim front, promoting the formation of a thin slag rim. This study enhances the understanding of slag rim formation in highly crystalline mold powders and provides critical insights into the control of longitudinal surface cracks in hypo-peritectic steel.

This study investigates the microstructure and co-precipitation behavior of multicomponent (Ni(Al,Mn) and Cu) nanoparticles in the weld heat-affected zones of high-strength low-carbon steel. Through thermal simulations, the intercritical, fine-grained, and coarse-grained heat-affected zones were systematically characterized to elucidate the interplay between the microstructure, precipitation, and mechanical properties. At a heat input of 30 kJ·cm⁻¹, Ni(Al,Mn) nanoparticles dissolve in the intercritical heat-affected zone, followed by dense reprecipitation coupled with significant coarsening of Cu particles during cooling, thereby retaining high strength but reducing impact toughness to (142 ± 10) J (compared to (205 ± 8) J of the base metal). The fine-grained heat-affected zone, under the same heat input, exhibits a refined ferritic–bainite matrix with a few fine Ni(Al,Mn) and slightly coarsened Cu particles, thus enhancing plastic deformation capacity and resulting in superior impact toughness of (196 ± 7) J. Despite complete dissolution of original precipitates at peak temperatures in the coarse-grained heat-affected zone, re-precipitated nanoparticles provide effective strengthening effect, compensating for grain coarsening and dislocation recovery and resulting in an impressive impact toughness of (186 ± 6) J. The toughening mechanism is primarily attributed to the synergistic actions of the matrix, precipitates, and deformation twins. These findings provide mechanistic and quantitative insights for developing processing–microstructure–property relationships in different welding heat-affected zones, and this framework can be further utilized to optimize welding parameters for tailored applications.

The influence of different solution and aging conditions on the microstructure, impact toughness, and crack initiation and propagation mechanisms of the novel α + β titanium alloy Ti6422 was systematically investigated. By adjusting the furnace cooling time after solution treatment and the aging temperature, Ti6422 alloy samples were developed with a multi-level lamellar microstructure, including microscale α colonies and α_p lamellae, as well as nanoscale α_s phases. Extending the furnace cooling time after solution treatment at 920°C for 1 h from 240 to 540 min, followed by aging at 600°C for 6 h, increased the α_p lamella content, reduced the α_s phase content, expanded the α colonies and α_p lamellae size, and improved the impact toughness from 22.7 to 53.8 J/cm². Additionally, under the same solution treatment, raising the aging temperature from 500 to 700°C resulted in a decrease in the α_s phase content and a growth in the thickness of the α_p lamella and α_s phase. The impact toughness increased significantly with these changes. Samples with high α_p lamellae content or large α_s phase size exhibited high crack initiation and propagation energies. Impact deformation caused severe kinking of the α_p lamellae in crack initiation and propagation areas, leading to a uniform and high-density kernel average misorientation (KAM) distribution, enhancing plastic deformation coordination and uniformity. Moreover, the multidirectional arrangement of coarser α colonies and α_p lamellae continuously deflect the crack propagation direction, inhibiting crack propagation.

Introducing Ti₂AlC particles into TiAl alloys can effectively improve their strength, but this can also lead to stress concentration at the interface, resulting in the reduction of ductility. Therefore, Mn is adopted to synergistically improve the strength and ductility of the Ti₂AlC/TiAl composite through solid solution and interface manipulation. The first-principles calculation shows the Ti–Mn bonds are formed at the Ti₂AlC/TiAl interface after Mn doping, characterized primarily by metallic bonds with some covalent bonding. This combination preserves strength while enhancing ductility. Then, Ti₂AlC/TiAl–Mn composite is prepared. The Ti₂AlC, with an average size of 1.6 µm, is uniformly distributed within the TiAl matrix. Mn doping reduces the lamellar colony size and lamellar thickness by 25.1% and 27.4%, respectively. A small quantity of Mn accumulates at the boundaries of the lamellar colonies. The Mn content must be controlled to avoid segregation, which may negatively impact performance. The yield stress, ultimate compressive stress, fracture strain, and product of strength and plasticity of the Ti₂AlC/TiAl–Mn composite have been increased by 5.5%, 11.5%, 10.4%, and 23.0%, respectively, compared to those of the Ti₂AlC/TiAl composite. The enhancement in strength is due to the combined effects of grain refinement, solid solution of Mn, and twining strengthening. Grain refinement and twin strengthening also can reduce stress concentration and improve ductility. In addition, at the electronic level, the Ti–Mn bond formed at the interface is contributed to the improvement of ductility.

Microbial contamination and the resulting corrosion in aircraft fuel system pose a serious threat to flight safety. Revealing the corrosion behavior and mechanism of fuel-degrading microorganisms on tank materials is crucial for developing effective mitigation strategies. In this study, the corrosion mechanisms of two representative hydrocarbon-degrading bacteria, Alcanivorax dieselolei and Microbacterium oxydans, toward AA7075 aluminum alloy, were systematically investigated. A combination of biofilm characterization, electrochemical testing, and surface/corrosion product characterization was employed. Both strains markedly accelerated the corrosion of AA7075, as evidence by the progressive decrease in polarization resistance and the pronounced rightward shift of the potentiodynamic polarization curves. Moreover, the difference between the pitting potential (E_pit) and the corrosion potential (E_corr) (ΔE = E_pit − E_corr) decreased due to microbial activities, indicating a pronounced tendency toward accelerated pitting corrosion. Corrosion morphology analysis revealed that both microbes promoted localized pitting corrosion. Furthermore, analysis of aviation kerosene composition indicated that both bacteria accelerated the degradation of C8 and C9 alkanes. These findings highlight the multiple threats of microbial contamination, material degradation, and fuel quality deterioration in fuel systems and underscore the need for targeted protection strategies for marine aviation operations.

This study investigates the anisotropic thermal conductivity of aluminum matrix composites reinforced with graphene nanoplates (GNPs) and in situ ZrB₂ nanoparticles, while simultaneously maintaining high strength and toughness. A discontinuous layered GNPs–ZrB₂/AA6111 composite was prepared using in situ melt reactions and semi-solid stirring casting technology, combined with hot rolling deformation processing. Microstructural analysis revealed that the GNPs were aligned parallel to the rolling direction–transverse direction (RD–TD) plane, whereas the ZrB₂ nanoparticles aggregated into cluster strips, collectively forming a discontinuous layered structure. This multilayer arrangement maximized the in-plane thermal conductivity of the GNPs. The tightly bonded GNP/Al interfaces with the locking of CuAl₂ nanoparticles ensured that the GNPs fully exploited their high thermal conductivity. Therefore, the GNPs–ZrB₂/AA6111 composite achieved high in-plane thermal conductivity (230 W/(m·K)), which is higher than that of the matrix (206 W/(m·K)). The improved in-plane thermal conductivity is primarily attributed to the exceptionally high intrinsic in-plane thermal conductivity of the GNPs and their two-dimensional layered structure. However, the composite exhibited pronounced thermal conductivity anisotropy in the in-plane and through-plane directions. The reduced through-plane thermal conductivity is predominantly caused by the intrinsically low through-plane thermal conductivity of the GNPs and the increased interfacial thermal resistance from the additional grain boundaries.

Lithium–sulfur (Li–S) batteries boast a theoretical energy density as high as 2600 Wh·kg⁻¹, positioning them as a highly attractive option for future advanced energy storage systems. Challenges such as slow transformation kinetics and shuttle effects associated with lithium polysulfides (LiPSs) have seriously hindered their practical applications. In this paper, we present a new method for the synthesis of hollow carbon-sphere-supported Co monatomic catalysts (Co–N–C). This new synthesis method achieves pyrolytic coordination using a precursor rich in imide (–RC=N–) polymers. This synthesis method not only improves the adsorbability and catalytic activity of LiPS but also significantly weakens the shuttle effect and generates Co–N–C with superior conductivity, abundant hollow structures, and a high specific surface area, thus efficiently capturing and restricting the movement of LiPS intermediates. The dispersed Co monoatomic catalysts (Co SACs) were anchored to a highly conductive nitrogen-doped carbon framework and exhibited symmetric N-coordination active sites (Co–N₄) to ensure fast redox kinetics of LiPS and Li₂S₂/Li₂S solid-state products. The lithium–sulfur battery with Co–N–C as the sulfur carrier showed excellent discharging capacity of 1146.6 mAh·g⁻¹ at a discharge rate of 0.5 C and maintained excellent performance at a high discharge rate of 2 C. The capacity decay rate in 500 cycles was only 0.086% per cycle, reflecting excellent long-term cycle stability. This study highlights the key role of the synergistic effect between single-atom cobalt catalysts and hollow carbon spheres in enhancing the efficiency of lithium–sulfur (Li–S) batteries. It also provides valuable insights into the construction and fabrication of highly active monatomic catalysts. The catalytic conversion efficiency of lithium polysulfides is significantly enhanced when embedded in hollow carbon architectures, which serves as a critical strategy for optimizing the electrochemical behavior of next-generation Li–S batteries.

The rapid expansion of the photovoltaic industry has generated heavily oxidized waste silicon (wSi), which hinders efficient recycling owing to its small particle size and uncontrolled surface oxidation. This study introduces a molten salt electrochemical strategy for converting photovoltaic wSi into NiSi₂–silicon nanorods (NiSi₂–SiNRs) as high-performance anode materials for lithium-ion batteries. A stable oxidized passivation layer is formed on the wSi surface via controlled oxidation, and further in situ generated highly active NiSi₂ droplets. The molten salt electric field modulates the surface energy of silicon, while particle integration drives localized directional growth, enabling the self-assembly of NiSi₂–SiNRs composites. These NiSi₂–SiNRs anodes exhibit rapid ion transport and effective strain buffering. The high aspect ratio of SiNRs and the presence of retained NiSi₂ facilitate both longitudinal and transverse Li⁺ diffusion. Owing to their robust structural design, the NiSi₂–SiNRs anode achieves an excellent initial Coulombic efficiency of 91.61% and retains 72.99% of its capacity after 800 cycles at 2 A·g⁻¹. This study establishes a model system for investigating silicide/silicon interfaces in molten salt electrochemical synthesis and provides an effective strategy for upcycling photovoltaic wSi into high-performance lithium-ion battery anodes.

Magnesium-based anode materials have attracted significant attention in the energy storage domain because of their high theoretical capacities and low electrochemical potentials. However, in conventional electrolyte systems, magnesium metal electrodes dynamically generate an ion-blocking surface layer, resulting in prominent voltage polarization, which severely limits their practical applications. In this study, ZIF-8/carbon nanotubes (CNTs) coatings were used to modify the anodes of magnesium batteries. Compared with the unaltered magnesium battery, the voltage lag time of the ZIF-8/CNTs coating was shortened from 4 s before modification to 0.26 s, and the battery impedance was lowered by two orders of magnitude. The duration of the discharge platform was increased from 4 h before modification to 6–10 h, the anode utilization rate was more than doubled, and the specific energy density was significantly enhanced compared with the battery before modification. The mechanism indicates that the ZIF-8/CNTs coating can limit the infiltration of corrosive substances, extend their transmission path, and offer more effective protection to the magnesium anode. The incorporation of CNTs improves the conductivity of the battery, and it significantly improves the electrochemical performance of the magnesium battery.

A novel trace nickel (Ni) doped tungsten (W) matrix with coated Ni on W grains was prepared by powder metallurgy method. The introduction of Ni can inhibit the reaction between W and barium–calcium aluminates (Ba–Ca aluminates) during the impregnation process of the matrix. After cathode activation, the surface Ba: O molar ratio is 0.88:1.00, much higher than the Ba dispenser cathode without Ni doping. The XPS results of the cathode surface showed that the metallic Ba appeared on the activated cathode surface, forming dipoles with oxygen, and effectively reducing the cathode surface work function. The pulse electron emission current density at 1100°C_b (brightness temperature) was 18.26 A/cm², and the calculated work function was 1.97 eV. It has a low evaporation rate and the accelerated lifetime test predict a lifetime of over 160000 h. First-principles calculations showed that the charge transfer and dipole moment in the NiW–BaO system were both increased compared to the Ba dispenser cathode, thus improving the emission performance of the Ni–W mixed matrix cathode.

The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave (EMW) absorbers to meet the applicability and versatility in various applications. Herein, a dual-network (DN) gel was successfully prepared using acrylamide and sodium lignosulphonate as the basic units by simple chemical cross-linking and physical cross-linking methods. Specifically, the hydrogel forms two types of cross-linking networks through metal coordination and hydrogen bonding. Benefiting from the combined effects of dipole polarization and conductivity loss, the gel achieves an effective absorption bandwidth (EAB) of 6.74 GHz at a thickness of only 1.89 mm, demonstrating excellent EMW absorption performance. In addition, this unique structural configuration endows the EMW absorber with multifunctional features, such as remarkable tensile strength, good environmental compatibility, ultraviolet (UV) resistance, and excellent adhesion. Integrating multiple functional features into the EMW gels displays a broad application prospect in a variety of application scenarios. This research reveals the significance of DN structure design in the electromagnetic wave absorption (EWA) performance of gel-based materials, providing a substantial foundation for the multifunctional design of gel-based absorbers.

With growing concerns regarding electromagnetic pollution, low-cost, environmentally friendly, and high-performance electromagnetic wave absorption (EWA) materials have attracted significant attention. This paper reports on the synthesis of porous Fe₃O₄/C composites that incorporate dielectric and magnetic loss mechanisms via the carbothermal reduction method and optimization of waste ratio to enhance EWA performance. The Fe₃O₄/C composites with 10wt% soybean residues (Fe₃O₄/C-10), demonstrated the best EWA performance, achieving the minimum reflection loss of −56.4 dB and a bandwidth of 2.14 GHz at a thickness of 2.23 mm. This enhanced EWA performance is primarily attributable to improved impedance matching and the synergistic effect between dielectric and magnetic losses. Furthermore, radar cross-sectional simulations confirmed the practical feasibility of the porous Fe₃O₄/C composites. This study proposes a viable strategy for utilizing soybean residue and electrolytic manganese residue, highlighting their potential applications in EWA.

Waste graphitization cathode carbon blocks are a type of hazardous solid waste generated during the aluminum electrolysis process, and their proper disposal is a key step in the resource utilization of discarded graphite. This study utilizes the porous “defect advantage” of a cathode carbon block matrix to prepare silicon-doped and asphalt-coated detoxified and purified waste graphitization cathode carbon blocks for use as high-performance silicon/carbon composite anode materials. The results show that the uniformly silicon-doped silicon/carbon composite material features a unique amorphous carbon-encapsulated “locked silicon” structure, which effectively addresses issues such as cathode volume expansion, excessive growth of the solid electrolyte interphase (SEI) film, and poor electrical contact between active materials. Consequently, electrochemical performance is enhanced. After assembly in a half-cell, the PSCC/10%Si@C (purified waste graphitization cathode carbon/10%Si@C) material exhibits optimal electrochemical stability, with an initial charging specific capacity of 514.5 mAh/g at 0.1 C (1 C = 170 mA/g) and a capacity retention rate of 95.1% after 100 cycles. At a charge rate of 2.0 C, a specific capacity of 216.9 mAh/g is achieved. This technology provides a new pathway for the economical and high-value utilization of waste cathode carbon blocks and the development of low-cost, high-performance anode materials.

Coal cinder is an abundant byproduct of the extensive consumption of coal in industrial production and daily life. Making full use of the cinder is conducive to a low-carbon economy. In this study, inspired by the burning of coal, a new method for constructing a silica-based composite porous material (SiO₂-CPM) was developed by combusting a siloxane-modified anthracite coal gel (CSiO₂ gel). During this process, the combustion product was directly converted into a porous material, and the calorific value of the coal remained nearly unchanged (∼98% of the original calorific value was retained), demonstrating the viability of this method for energy-efficient applications. The SiO₂-CPM exhibited an ultra-low thermal conductivity (0.036 W/(m·K) at room temperature), outperforming conventional insulation materials (e.g., cotton ∼0.05 W/(m·K)). Additionally, it showed enhanced mechanical strength (fracture stress of 41.8 kPa) compared to the powder state of the coal cinder. Experimental results indicate that the amount of siloxane, structure-directing agent, and an acidic environment were critical for mechanical enhancement. The SiO₂-CPM showed good dimensional stability against thermal expansion and exhibited excellent thermal insulation and fire resistance even at 900°C. Meanwhile, the SiO₂-CPM with complex geometry could be easily fabricated using this method owing to the excellent shaping ability of the CSiO₂ gel. Compared to conventional methods such as sol–gel synthesis or freeze-drying, this approach for fabricating SiO₂-CPM is simpler and cost-effective and allows the direct utilization of coal cinder post-combustion.

The high-temperature interaction of nanostructured Lu₂Si₂O₇ environmental barrier coatings (EBCs) with calcium–magnesium–aluminosilicate (CMAS) was investigated at 1400°C for 1, 10, 25, and 50 h to evaluate the coating’s resistance to CMAS corrosion. The results indicate a phase transformation over time, transitioning from Ca₂Lu₈(SiO₄)₆O₂ apatite and Lu₂Si₂O₇ to solely Lu₂Si₂O₇. The interaction of the Lu₂Si₂O₇ coating with the CMAS melts was divided into three stages based on the corrosion reaction behavior. The delamination cracks were distributed throughout the interface between the Si bond layer and Lu₂Si₂O₇ layer after corroded at 1400°C for 50 h, signifying coating failure. In addition, the influence of monosilicates, disilicates, and corrosion duration on the recession layer thickness was analyzed by comparing previous reports on RE₂SiO₅/RE₂Si₂O₇ coatings (RE = Gd, Yb, Lu, Er). Furthermore, the variation in the thermally grown oxide layer thickness in CMAS-corroded Lu₂Si₂O₇ coatings was systematically investigated.