Mo14Re powders were prepared by high-energy ball milling (HEBM) and spray drying-hydrogen reduction (SPHR), separately. Then, the Mo14Re alloys were obtained by spark plasma sintering (SPS). The phase structure, microstructure, element distribution, and grain size were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). The deformation mechanisms of Mo14Re alloy under room temperature tension and compression were discussed. The XRD results indicate that the (101)-spacing of the Mo14Re-SPHR is smaller than that of the Mo14Re-HEBM. The EDS results show that the segregation of Re is observed at the grain boundary of the Mo14Re-HEBM, while uniform elements distribution in the Mo14Re-SPHR alloy. The room temperature compression results show that the compressive yield strength of the Mo14Re-SPHR is 679.11 MPa, higher than that of the Mo14Re-HEBM (602.71 MPa). EBSD results show that when the compression deformation is larger than 5.0%, the proportion of grains with {123} <111> as the main slip system in Mo14Re-SPHR increases, while the proportion of grains with {110}<111>and {112}<111> as the main slip systems decreases. The change trend of the three slip systems in Mo14Re-HEBM is opposite to that in Mo14Re-SPHR, resulting in a strain hardening rate of Mo14Re-HEBM higher than that of Mo14Re-SPHR. Room temperature tensile results show that Mo14Re-SPHR exhibits better plasticity and toughness.

Mo-Re alloys are considered promising candidate materials for high-temperature applications. This study investigated the creep properties of Mo14Re alloy under temperatures of 1200-1300 degrees C and applied stresses of 50-100 MPa. The stress exponent at 1200 degrees C was calculated as 3.90 indicating that the creep rate is primarily controlled by the dislocation climb mechanism. The analysis of the microstructure after creep together with the changes in activation energy indicates that the increase in temperature leads to a transition in the dominant diffusion mechanism from grain boundary diffusion to lattice diffusion. Under 1200 degrees C/50 MPa creep conditions, dislocation reorganization into cell structures through climb, where thickened cell walls effectively pinned dislocations and significantly increased the proportion of low-angle grain boundaries (LAGBs). However, elevated temperature or stress reduced the LAGBs fraction and increased the steady-state creep rate. Texture evolution and grain refinement confirmed that stress enhancement promoted subgrain rotation/coalescence, driving the transformation of LAGBs into high-angle grain boundaries (HAGBs). In addition, elevated temperatures enhanced grain boundary mobility and the driving force for dislocation cell merging. These microstructural characteristics revealed that neither elevated temperature nor stress altered dislocation climb as the creep rate controlling mechanism. However, the dislocations climb rate is affected by temperature and stress. Increased stress shifts the predominant control factor of dislocation climb rate from dislocation cells to jog. Elevated temperature raises vacancy concentration, thereby enhancing dislocation climb rate.

Photoelectrochemical cell (PEC) represents a sustainable technology that could convert solar energy into solar fuels. Synthesis of porous carbon nitride (CN) photoanode with large active surface is crucial for efficient PEC water splitting, however, remains challenging. This work reported a porous CN photoanode with large active surface enabled by melamine-urea comonomer film assembly followed with in-situ thermal condensation. It imparts large surface area, broadened light harvesting, facilitated charge separation, and significantly enhanced electrochemically active surface area. The as-synthesized CN photoanode delivered impressive PEC water splitting performance with photocurrent (at 1.23 V) up to 190 μA/cm2 in KOH solution, 2.2 times higher as that of compact CN photoanode. After addition of sacrificial agent in electrolyte, the photocurrent is boosted to 420 μA/cm2. Their IPCEs at 400 nm are 13 % and 32 %, respectively. The improved PEC activity was also visually evidenced by scanning electrochemical microscope measurement. The concept of comonomer film assembly-initiated porous CN film synthesis in this work provides a reliable approach to tailor the photophysical properties of in-situ synthesized CN film, which paves a pathway to enhance/broaden the applications of CN in electronic devices, not just limited to photoelectrochemical water splitting.

This study systematically examined the influence of annealing temperature (1050-1350 degrees C) on microstructural evolution and mechanical properties of molybdenum-rhenium (Mo-Re) alloys with varying Re content (14-41 wt%). The microstructures such as crystal orientation, average grain size and dislocation distribution of the Mo-Re alloys were determined by electron back scatter diffraction. Subsequently, the effects of Re content and microstructure on the hardness and compressive yield strength of Mo-Re alloys were discussed. It is observed that the hardness and compressive yield strength exhibit a consistent increase with Re content, resulting from a concurrent increase in dislocation density and reduction in grain size. The geometrically necessary dislocation (GND) density plot indicates that Re contributes to enhancing the stability of dislocations in Mo-Re alloys. Recrystallization occurring below the engineering recrystallization temperature is attributed to subgrain boundary assimilation, whereas above this temperature, this process is driven by grain boundary migration. During annealing, Re governs the transition of the primary slip system from {110}<111> to {123}<111>, whereas the annealing temperature drives its transition to {112}<111>. The dependence of mechanical properties on composition, grain size, and dislocation density is accurately captured by the strengthening mechanism formula. This study provides valuable insights for tailoring the properties of Mo-Re alloys in industrial manufacturing.

In this work, tungsten-rhenium (W-Re) alloys with varying Re concentrations (10, 15, 20, 25 wt%) are fabricated using powder metallurgy techniques. The influence of Re3W (chi phase) addition on the mechanical properties of these alloys was systematically investigated. A clear trend of increasing macrohardness with Re content is observed in the W-Re alloys over the investigated composition range (10-25 wt%), irrespective of the addition of the chi-phase. Whereas, The compressive elastic limit of W-Re alloys, both with and without the addition of chi-phase particles, decreases with increasing Re content. Nanoindentation results indicate that the microhardness of the alloys increases with Re content up to 20 wt%. In contrast, the addition of chi-phase particles leads to a decrease in the microhardness of W-Re alloys with increasing Re content. Molecular dynamics simulations reveal that the tensile and compressive strength of W-Re alloys decrease with increasing Re content, a trend further exacerbated by the introduction of the chi-phase. It is attributed to the severe stress concentration induced by the presence of chi-phase. Rhenium clusters act as stress concentrators in a uniform stress field, but not under non-uniform conditions. Higher rhenium content enhances the tendency for Re cluster formation, which lowers the compressive elastic limit strength of the W-Re alloy. Concurrent microstructure analysis indicates that failure under compression is initiated by the crushing of the chi-phase, whereas tensile failure originates from interfacial cracking. Our work advances the understanding of how intermetallic compounds influence the mechanical properties of W-Re alloys, offering crucial insights for W-Re alloy design.

In this work, the effects of annealing temperature (1250-1450 degrees C) and duration (0.5-2 h) on the microstructure evolution and mechanical properties of the rotary forged Mo-41 wt %Re alloy were examined. The microstructure and phase composition are determined by the optical microscope and X-ray diffraction, respectively. The correlation between grain size and mechanical properties was discussed in the framework of Hall-Petch equation. It is found that as the annealing temperature rises and duration extends, the average grain size of Mo-41 wt %Re alloy increases, whereas hardness and compressive elastic limit decrease. The recrystallization temperature of the Mo-41 wt %Re alloy is determined to be 1350 degrees C. Optical microscopy and XRD analyses reveal that the grain growth during the recrystallization of Mo41Re alloy under annealing proceeds in two distinct stages: initial coarsening of grains, followed by further growth accompanied by grain reorientation. Grain growth during recrystallization exhibits prolonged incubation periods when the temperature driving force is inadequate. The crystallographic plane orientation transformation of grains from (200) and (211) to (110) is energetically more favorable than the reverse transition from (110) to (200) and (211). The incorporation of dislocation effect enables the modified Hall-Petch relationship to better characterize the interdependence between grain size, dislocation density, and mechanical properties in severely deformed then annealed Mo-41 wt %Re alloy. These findings contribute to a better understanding of microstructure-property relationships in molybdenum-rhenium alloys, offering important references for process optimization in annealing treatments.

Single-crystal nickel-rich LiNixCoyMn1-x-yO2 (SCNCM, x ≥ 0.9) has emerged as a promising cathode material for lithium-ion batteries, owing to high energy density and robust crystal structure. However, severe phase transitions contribute to performance degradation and mechanical instability during long-term cycling. To address these challenges, a uniform liquid film strategy is proposed for the in situ construction of a 3D Li1.3Al0.1Sc0.2Ti1.7(PO4)3 (LASTP) conductive network at (003) plane of SCNCM interface. This network establishes an interface bonding-via Sc─O and Al─O bonds-between SCNCM particles and LASTP. The LASTP framework facilitates rapid lithium-ion conduction, while the Sc─O and Al─O bonds stabilize oxygen vacancies, thereby suppressing oxygen evolution and enhancing interfacial structural integrity. This mitigates the irreversible phase transition (especially O3 to O1) and lattice deformation. The feasibility and effectiveness of this 3D network approach are substantiated through a combination of experimental investigations, DFT calculations, BEVL network analysis, and COMSOL simulations. As expected, the pouch-type full battery can achieve a satisfactory capacity retention of 83.7% after 1900 cycles (85.8% at 2.8-4.25 V after 1200 cycles). Furthermore, it provides an extraordinary capacity retention of 79.1% with 161.9 mAh g-1 after 800 cycles in 2.8-4.4 V at 50 °C.

Correction for ‘A relaxor ferroelectric polymer with an ultrahigh dielectric constant largely promotes the dissociation of lithium salts to achieve high ionic conductivity’ by Yan-Fei Huang et al. , Energy Environ. Sci. , 2021, 14 , 6021–6029, https://doi.org/10.1039/D1EE02663A.

The creep properties of W-4Re-0.27HfC (wt%) alloy at temperatures of 1800, 1900, and 2000 degrees C was investigated by SEM, EBSD, and density functional theory (DFT). The grain size, grain type, dislocation density, fracture morphology, and the mechanism of creep failure of W-4Re-0.27HfC alloy ware analyzed after creep at different temperatures. The results indicate that the steady-state creep rates at creep temperatures of 1800, 1900 and 2000 degrees C are 9.8x10-6, 1.0x10-5, and 2.1x10-5 s-1, respectively. With the increase in creep temperature, the proportion of low-angle grain boundaries decreases while the proportion of high-angle grain boundaries increases, resulting in the increase in average grain size. During the creep process, grain undergoes plastic deformation, forming numerous ductile dimples. The poor deformation compatibility of high-angle grain boundaries leads to the formation of voids, accelerating creep failure. EDS results illustrate that the HfC particles in W-4Re-0.27HfC alloy are oxidized severely. DFT calculations show that the interface binding energy between HfC and matrix decreases from-11.221 J/m2 to-3.935 J/m2 after HfC oxidation, reducing the strengthening effect of the second phase.

Favorable crystal surface exposure of the substrate enables the growth of semiconductor films with strong adhesion and fast charge transfer at the interface. Herein, the exposure of (211) of SnO2 : F (FTO) via surface etching led to the uniform synthesis of a crystalline carbon nitride (CN) film. The as-synthesized CN film showed preferable electron transfer from CN to FTO, low structural defects, and excellent charge separation and transport. It produced a state-of-the-art photovoltage of 0.64 V. Photoelectrochemical (PEC) water splitting investigation demonstrated excellent performance with low water oxidation onset potential of 0.22 V vs. RHE and an impressive unbiased photocurrent of 12.4 mu A cm-2. The use of an NiCo-LDH cocatalyst led to a high photocurrent of 440 mu A cm-2 in a triethanolamine containing electrolyte, with a H2 yield of 40.9 mmol m-2 h-1 and IPCE (400 nm) of 26.7%. This work demonstrates a good example for the growth of high-quality CN films with high PEC performance via substrate surface engineering, which could also expand other applications of CN films.

Single-crystal and polycrystalline particles are two representative morphological structures commonly employed in commercial high-nickel layered oxide cathodes, each with distinct functional characteristics. Single-crystal materials feature high structural integrity and excellent compaction density, enabling improved cycling stability and mechanical robustness. In contrast, polycrystalline particles possess higher surface area and interfacial reactivity, which contribute to enhanced initial capacity and lithium-ion transport kinetics, but are prone to microcrack formation and accelerated degradation during long-term operation. Considering these complementary attributes, this study proposes a morphology-integrated composite strategy, combining the two particle types in varying ratios to construct structurally and functionally optimized cathodes. A series of composites were systematically investigated through multi-scale characterizations, including structural stability, lithium-ion diffusion, impedance evolution, and electrochemical reversibility. The results demonstrate that composites with a moderately increased proportion of single-crystal particles exhibit the most favorable balance between rate capability and cycling durability. Such composites benefit from the compact structural framework and stability of single-crystal domains, while retaining the electrochemical activity conferred by polycrystalline regions. This morphology-driven synergy effectively mitigates interfacial degradation and polarization buildup during extended cycling. Among the tested configurations, the composite containing a moderate dominance of single-crystal material delivers the most stable and well-rounded performance. These findings highlight the value of rational morphological engineering and multi-dimensional analysis in the design of advanced high-nickel cathodes, offering a practical route toward high-energy, long-life lithium-ion batteries.

Due to their excellent high-temperature mechanical properties and good room-temperature machinability, molybdenum-rhenium (MoRe) alloys have been widely used as high-temperature structural materials. This study investigates the creep properties of the MoRe alloys prepared by powder metallurgy with the Re contents of 5, 14, and 41 wt%. The results showed that the steady-state creep rates of Mo5Re, Mo14Re, and Mo41Re under creep conditions of 1350 K and 100 MPa were 2.21 x 10(-7) /s, 1.58 x 10(-7) /s, and 8.14 x 10(-8) /s, respectively. It is revealed that the creep resistance increases with Re content. The changes in the proportions of the slip systems in MoRe alloys before and after creep were analyzed. The results show that the proportion of {112}< 111 > or {123}<111 > slip systems rises with increasing Re content. DFT results indicate that the unstable stacking fault energy of slip systems decreases with the increase of Re content, which implies that the activation energy barrier of slip systems decreases with the increase of Re content. This result indicates that the increase of Re content promotes the activation of multiple slip systems. The activation of multiple slip systems enables the high-temperature deformation capacity of MoRe alloys to improve with increasing Re content. Grain state and dislocation morphology evolution demonstrate that increased Re content suppresses dislocation climb behavior in MoRe alloys. Additionally, in Mo41Re, a small number of Re atoms aggregate to form Re clusters. The interaction between these Re clusters and dislocations further restricts dislocation migration. These factors collectively contribute to the improvement of creep resistance in MoRe alloys with increasing Re content.

Free barium (Ba) is critical to the formation of the active layer on the surface of dispenser cathode, which is contributed to the electron emission properties of the cathode. The Ba in the active layer of the dispenser cathode is generated by the chemical reaction between aluminate compounds and tungsten (W) under vacuum and high temperature. Nowadays, the effect of aluminate compounds on the generation of free Ba is not clear. In this work, aluminate impregnants called 411, 532 and 612 impregnants were prepared by coprecipitation method. The structure of the dominate compounds in 411, 532 and 612 impregnants were determined with density functional theory (DFT) calculation and Rietveld structure refinement. It was found that the dominate compounds of 411, 532 and 612 impregnants are Ba3.5Ca0.5Al2O7, Ba5CaAl4O12 and Ba3CaAl2O7, respectively. Then, the temperature dependence of the thermodynamic properties, such as Debye temperature, entropy, heat capacity and enthalpy, of the aluminate compounds were calculated. Based on the thermodynamic properties, the potential chemical reaction between aluminate compounds and W are energetically determined by deviation Gibbs energy. The effects of different aluminate compounds on the free Ba generation were evaluated with the equilibrium Ba(g) amounts that generated by the chemical reactions between aluminate compounds and W. It is shown that the equilibrium Ba(g) amounts generated by Ba3.5Ca0.5Al2O7 is higher than that by Ba5CaAl4O12 and Ba3CaAl2O7, implying the superiority of electron emission performance of Ba3.5Ca0.5Al2O7. The electron emission densities of the dispenser cathodes that impregnated with the 411, 612 and 532 impregnants are 5.06, 4.31 and 4.05 A/cm2, respectively. It is revealed that the Ba3.5Ca0.5Al2O7 has superiority in generating free Ba, which agreed well with thermodynamic simulation results.

Carbon nanotubes(CNTs)are tubular structures composed of highly graphitized atoms.Due to the sp2 hybrid electron orbital structure,CNTs possess a variety of unique physical and chemical properties,such as high mechanical strength,excellent optical anisotropy and good electrical conductivity.Therefore,CNTs are promising advanced materials that can be used in areas of material strengthening,energy conversion and electronic devices.The structures and properties of CNTs can be tuned by regulating the growth environment of CNTs.Nevertheless,the growing process of CNTs is very complicated,and highly depended on raw material,preparation method and growth environment,which consequently determine the growth rate,microscopic morphologies and final properties of CNTs.In the present paper,the effects of fabrication methods,substrates,catalysts,and growth environment on the microscopic morphologies and properties of CNTs were reviewed,and the growth mechanisms of CNTs are discussed.We also pay attention to the application of CNTs in the areas of energy storage,material toughening and catalytic hydrogen production.The present deficiencies and future development directions on the preparation and controlled growth of CNTs are figured out,which provides guidance for the controlled growth and large-scale preparation of CNTs.

W-Re alloys are one of the most important refractory materials with excellent high-temperature performance that were developed to improve the brittleness of tungsten. In the present work, we firstly summarized the research progress on the preparation and strengthening methods of a W-Re alloy. Then, the strengthening mechanisms of the W-Re alloy were discussed, including the influence of Re, solid solution strengthening, second-phase reinforcement and fine-grain strengthening. The results showed that the softening effect of Re was mainly related to the transformation of the preferred slip plane and the introduction of additional d-valence electrons. Some transition elements and refractory metal elements effectively strengthened the W-Re alloy. Carbides can significantly enhance the high-temperature mechanical properties of W-Re alloys, and the reasons are twofold: one is the interaction between carbides and dislocations, and the other is the synergistic strengthening effect between carbides and Re. The objective of this work was to enhance the comprehension on W-Re alloys and provide future research directions for W-Re alloys.

The improvement of Fe(III)/Fe(II) conversion efficiency and facilitation for recycling of Fe-based catalyst have dual economic and green benefits in the field of photo-Fenton-like for wastewater treatment. To achieve those purposes, we have designed and fabricated an S-scheme catalyst by in-situ growing magnetic sodium ferric silicate/ferroferric oxide-ferric oxide (SFS/M-FO) heterojunction. Our results demonstrated the mechanism of heterogeneous interface formation and S-scheme charge transportation between NaFeSi2O6 and alpha-Fe2O3 in the composite. Meanwhile, the semi-coherent interface in heterojunction could effectively reduce the charge transfer resistance. The incorporation of magnetic ferroferric oxide (Fe3O4) not only ensured high recoverability of the catalyst, but also facilitated charge transfer and improved light absorption capacity. The improved catalytic activity was derived from the combination of the S-scheme NaFeSi2O6/alpha-Fe2O3 heterojunction and Fe3O4 elec-tronic conductor. Therefore, the SFS/M-FO composite showed excellent tetracycline removal rate of 91.8% within 50 min in the photo-Fenton-like reaction. The ternary composite also held excellent performance, reus-ability and structural stability. The produced intermediates and three degradation pathways of tetracycline were identified by liquid chromatograph-mass spectrometer. This study offers a convenient way for combining high performance and magnetical retrievability by in-situ growth method for wastewater treatment.