High-temperature solid oxide electrolysis cells (SOECs) offer high energy efficiency and environmental compatibility for CO₂ conversion, yet currently face the critical challenge of phase instability and coke formation, especially under strong polarization conditions, which leads to device performance degradation or even failure. In this study, redox phase stable CeO₂ cathode materials were modified via co-doping with Mn and Ni, enabling the in situ formation of self-assembled and strongly coupled metal Ni/ceria heterostructures, and modification of bulk properties (increased redox Ce³⁺ active site numbers, Ni exsolution, oxygen defect concentration, and electrical properties), which consequently effectively enhances surface reaction kinetics and electrode series conductivity. The optimized Mn-Ni co-doped ceria (CMN) exhibited stable electrochemical performance for nearly 140 h at 750 ^oC with minimal degradation under mild electrolysis conditions. Under strong polarization (2.0 V), SOECs based on the CMN electrode delivered an impressive current density of 3.05 A cm^-2 at 800 ^oC, accompanied by reliable operational stability over the state-of-the-art Ni-based cermet electrode and widely investigated perovskite oxide cathode catalysts. These findings underscore the synergistic benefits of transition metal co-doping and in-situ heterostructure engineering in enabling high-performance, carbon-tolerant ceria-based electrodes for SOEC operation both under moderate and harsh conditions, approaching practical application.

The design of microstructures is essential for tailoring the microwave dielectric properties of ceramics, yet the structure-property relationship in tetragonal scheelite-structured ceramics remains insufficiently understood. In this study, first-principles calculations combined with experiments were used to systematically investigate the interrelations among sintering behavior, crystal structure, electrical characteristics, bond characteristics, and dielectric performance of NaSrLnMo₃O₁₂ (Ln = Ce, Pr, Eu, Y, Yb) ceramics. All compositions crystallized into a tetragonal scheelite structure (space group <em>I</em>4₁/<em>a</em>) and exhibited favorable dielectric properties with optimal sintering temperatures of 775 ~ 925 °C, <em>ε_r</em> = 9.8 ~ 10.34, <em>Q×f</em> = 30,487 ~ 69,445 GHz, and<em> τ_f </em>= −20.55 ~ −44.24 ppm/°C. Enhancement of <em>ε_r</em> originated mainly from the increased ionicity of Na/Sr/Ln-O bonds, while the improvement of <em>Q×f</em> was attributed to higher lattice energy of Mo-O bonds, elevated bond valence, and reduced ionic/electronegativity disorder. The negative shift of <em>τ_f</em> was primarily linked to the increased <em>α_L</em> of Na/Sr/Ln-O bonds. Furthermore, electrical characteristics and relaxation mechanisms were examined, and dielectric response in the terahertz range was confirmed. Finally, NaSrCeMo₃O₁₂ was employed to design and fabricate two antenna devices, verifying its potential for high-frequency communication. This work provides a systematic understanding of the role of Ln elements in optimizing the dielectric properties of tetragonal scheelite ceramics and clarifies the microscopic mechanisms underlying their performance.

Silicon carbide (SiC) fiber aerogels are promising materials for renewable energy and aerospace applications. However, conventional SiC aerogels often suffer from limitations such as single pore structures, inadequate mechanical strength, and high production costs, which severely restrict their practical application. Here, we designed and fabricated a hierarchical porous SiC microtube/nanowire composite aerogel derived from kapok fibers via an in-situ conversion strategy. This approach directly utilizes kapok hollow fibers to construct the SiC microtubule while simultaneously inducing the self-growth of SiC nanowires, achieving controllable hierarchical pore fabrication in a single step. Compared to conventional methods, this strategy significantly simplifies the fabrication process and enhances multifunctional performance through structural synergy. The unique microtube-nanowire heterostructure confers excellent electromagnetic wave absorption (minimum reflection loss of -56.39 dB, effective absorption bandwidth of 6.04 GHz at 2.0 mm) by enhancing interfacial polarization and optimizing impedance matching. The nanowire bridging effect achieves a compressive strength of 2.85 MPa, surpassing mechanical limits of conventional aerogels. Additionally, the aerogel exhibits superior thermal insulation (0.021 W·m⁻¹·K⁻¹) and pollutant adsorption capacity (45–67 times its weight). This research offers a new approach for developing high-strength, multifunctional SiC aerogels.

Developing high efficiency sintering technologies with mild conditions is crucial for reducing energy consumption and manipulating performances of ceramics. However, sintering ceramics at low temperatures in short times without pressure is challenging, due to their high melting points. Inspired by microwave resonance and dissolution-precipitation phenomena, an energy efficient sintering, microwave cold sintering process (MW-CSP), is proposed here to densify high-performance ceramics with significantly reduced sintering times and temperatures under pressureless conditions during the sintering stage. A range of ceramics including chlorides, oxides, phosphates and molybdates with various applications are shown to be well sintered by MW-CSP. TEM and phase-field simulation results demonstrate that the combination of transient liquid phase and microwave resonance improves the driving force of sintering. The mechanical and dielectric properties of selected materials are improved by 50 ~ 95%, while the energy consumption of MW-CSP is dramatically reduced by over 97% compared to other pressureless sintering technologies. These findings highlight the great potential of MW-CSP in efficiently densifying high-performance ceramics, opening up possibilities for energy saving sintering.

Advanced thermal management for extreme environments urgently demands materials that combine robust environmental stability with adaptive thermal conductivity (<em>κ</em>), specifically the highly desirable but rare positive temperature dependence of <em>κ</em>. While ceramics typically show phonon-dominated heat transfer with decreasing thermal conductivity at elevated temperatures, achieving an alloy-like positive <em>κ</em>-T relationship in ceramics holds a significant scientific and technological challenge with immense application value. To address this, we fabricated fully dense (&gt;98%) multicomponent nitride bulks via hot-press sintering using AlN as the matrix. Notably, the TiAlN system achieved a high room-temperature <em>κ</em> of 48.38 W/(m·K). Counterintuitively, increased diversity of metallic element induces severe lattice distortion that suppresses phonon thermal conduction, while simultaneously forming metallic nitride conductive networks that significantly enhance electronic thermal conductivity. This synergistic electron-phonon regulation successfully transforms the <em>κ</em>-T dependence from negative to positive. Remarkably, TiZrVCrAlN demonstrates a linear 112% <em>κ</em> increase from 8.65 W/(m·K) at -60 °C to 18.34 W/(m·K) at 900 °C, outperforming all known positive-κ ceramics in both operational temperature range and conductivity values. Moreover, it maintains robust mechanical integrity (24.5 GPa hardness, 273 MPa bending strength). This work elucidates the fundamental mechanism for achieving anomalous positive <em>κ</em>-T dependence in ceramics through electron-phonon synergistic regulation. These multicomponent nitrides, combining unprecedented positive <em>κ</em>-T behavior with excellent mechanical properties, present a breakthrough solution for intelligent thermal management, specifically enabling the development of structural-functional integrated components operating under extreme and varying thermal conditions.

The development of electrolytes with high ionic conductivity and stable electrode-electrolyte interfaces is crucial for the practical realization of solid-state sodium batteries. In this study, the effect of heteroatom doping in von-Alpen-type NASICON was investigated by substituting Zr⁴⁺&nbsp;with Mg²⁺, Zn²⁺, and La³⁺&nbsp;to enhance its material properties and evaluate its potential for solid-state sodium battery applications. Computational chemistry was employed to predict the thermodynamic stability influenced by dopant introduction and the changes in ionic conductivity arising from crystal structure distortion, with the predictions validated by experiments. The optimized Zn²⁺-doped NASICON (Zn-NZSP0.07) exhibited the highest total ionic conductivity of 2.74 × 10⁻³&nbsp;S cm⁻¹, representing a 4.5-fold increase compared to undoped NASICON (6.00 × 10⁻⁴&nbsp;S cm⁻¹). The material also showed a high relative density of 99.1%, indicating a compact and well-sintered microstructure, as confirmed by a three-point bending test. It further achieved a high critical current density of 1.4 mA cm⁻²&nbsp;in symmetric cell testing. Additionally, a Na₃V₂(PO₄)₃&nbsp;|| Zn-NZSP0.07 || Na cell delivered an initial capacity of 103.9 mAh g⁻¹&nbsp;at 0.1 A g⁻¹&nbsp;and retained 73.4% of its capacity after 200 cycles. These results demonstrate that optimal heteroatom doping is crucial for&nbsp;enhancing&nbsp;the performance of NASICON.

To address the persistent challenges of low sensing performance, ambiguous sensing mechanisms, and difficult portable monitoring in existing MXene-based NH3 sensors, this study developed a high-performance MoO3@Ti3C2TX room-temperature NH3 sensor through ultrasonic composite modification. The MoO3@Ti3C2TX sensor demonstrated significant sensitivity to NH3 at room temperature, with excellent long-term stability, fast response recovery time (14 s/24 s), and excellent selectivity, which are superior to those of most reported Ti3C2TX-based and intrinsic MoO3 sensors. Owing to the unique microstructure of MoO3@Ti3C2TX, the dual active sites of Ti3C2TX functional groups (–O/–F/–OH) and oxygen vacancies facilitate the oxidative adsorption and dissociation of NH3. The formation of interfacial Schottky junctions and charge regulation significantly enhanced the gas sensitivity of MoO3@Ti3C2TX toward NH3. Density functional theory (DFT) simulations further revealed an increased NH3 adsorption energy and strong atomic orbital hybridization at the heterointerface. Furthermore, this study integrated the MoO3@Ti3C2TX sensor into a multifunctional Internet of Things (IoT) monitoring system, which enabled real-time visualization of NH3 detection through threshold-triggered alarms, demonstrating its utility in smart agriculture.

The search for new materials with reliable molten calcium-magnesium-alumino-silicate (CMAS) resistance at elevate temperatures holds important significance for the development of advanced aeroengine. In the present study, a novel Y₄Al₂O₉/Y₂O₃ composite was designed and fabricated in dense sample using the hot-pressing method. The interactions and mechanisms between Y₄Al₂O₉/Y₂O₃ composite and CMAS at 1300 ℃ and 1500 ℃ for durations of 1 h, 4 h, 25 h, and 50 h were thoroughly explored. The results reveal that Y₄Al₂O₉/Y₂O₃ exhibits substantial resistance to CMAS infiltration at both temperatures, without notable grain-boundary penetration by CMAS glass. More importance, the incorporation of reaction active compositions in the composite accelerated the consumption of molten CMAS constituents and reduce its corrosive activity, which is recognized as the crucial principle for composition design of anti-CMAS materials. This work provides valuable insights that guides the design of composition and advancement of superior CMAS-resistant materials.

To investigate the bonding behavior of SiC-free composite ceramics via spark plasma sintering, this study demonstrates the successful joining of B₄C–40 vol% TiB₂ ceramics using a Ti foil interlayer within the temperature range of 1000–1400 ^oC. The bonding mechanisms across temperatures were systematically elucidated through integrated approaches, including phase composition analysis, microstructural observation, thermodynamic and diffusion kinetic calculations. Results reveal that the competitive reactions between active Ti and ceramic phases drive a sequential compositional evolution at the joint interface: starting from pure Ti, the interface transitions to a mixture of TiB₂, TiC, TiB, and residual Ti, ultimately forming a stable TiB₂–TiC–TiB ceramic assemblage as temperature increases. Kinetic analysis shows that between 1000–1300 °C, reaction layer thickness follows a diffusion-controlled growth model, directly correlated with temperature via Arrhenius-type kinetics. At the highest temperature of 1400 °C, complete consumption of Ti yields a full-ceramic joint. Mechanical characterization indicates that these temperature-dependent microstructural changes significantly affect joint performance: the maximum shear strength of 72 MPa is achieved at 1300 °C, accompanied by crack penetration through the ceramic, reaction layer, and residual Ti layer.