This review systematically represents recent advances on the sol-gel synthesis of high-performance continuous alumina fibers. The analysis reveals that a precise control of microstructural characteristics, such as grain size, phase composition, and grain boundary properties, can profoundly affects the mechanical properties and high-temperature performance of the fibers. However, some substantial challenges persist in understanding the mechanisms of alumina fiber formation, achieving a precise process control, and enhancing performance in extreme environments. Accordingly, future research should focus on the following directions:

1) Transitioning from empirical trial-and-error to theoretically guided design via developing multiscale simulation techniques to inform holistic process optimization during fiber fabrication. Computational simulations can uncover underlying mechanisms to enable theory-driven fiber design. In an atomic scale, first-principles calculations and molecular dynamics simulations can reveal grain boundary segregation behavior of sintering aids such as rare-earth oxides. molecular dynamics can also simulate atomic rearrangement during α-Al₂O₃ phase transformation, clarifying heterogeneous nucleation mechanisms induced by iron sol additions. In a mesoscale, phase-field modeling can dynamically simulate densification-grain growth competition, grain boundary pinning by secondary phases, and defect evolution. In a macroscale, the fiber service failure can be simulated to correlate predicted microstructures to mechanical properties.

2) Advancing from static cross-sectional observation to dynamic in-situ characterization via developing advanced in-situ techniques to directly elucidate fiber microstructural evolution mechanisms. The existing understanding of microstructural evolution relies largely on static examination of samples from different processing stages, rendering direct validation difficult and many conclusions speculative. Future work should emphasize in-situ experimental methods applicable to both the preparation and service of alumina fibers, enabling the real-time observation of microstructural evolution.

3) Bridging a gap between laboratory samples and industrial products via addressing challenges in continuity, stability, and cost efficiency in fiber manufacturing. Future efforts should focus on developing online monitoring and feedback systems for precursor sols to maintain viscosity and spinnability, advancing intelligent temperature and tension control to minimize fiber bending damage while collecting real-time data on the effects of thermal and tensile variations and exploring low-cost alternative aluminium sources paired with optimized sintering protocols to reduce energy consumption.

4) Addressing next-generation application requirements via investigating fiber performance limits under ultra-high-temperature, long-duration service conditions and developing novel reinforcement strategies. Systematic studies should be conducted on creep mechanism transitions, grain boundary evolution, and the performance degradation mechanisms in high-temperature environments such as steam and air.

C-S-H/PCE nanocomposites represent a significant advancement over conventional accelerators, offering a synergistic approach to enhance early-age strength and durability in cement-based materials. This review systematically discusses the fundamental understanding of their synthesis, the complex interplay between C-S-H and PCE, their unique nucleation seeding mechanism, and the factors governing their performance. The development of novel metal-doped nanocomposites and the exploration of synergistic combinations with other admixtures expand their potential and effectiveness across diverse cementitious systems. These materials demonstrate clear advantages in enabling rapid strength development, improving microstructure, and facilitating sustainable construction practices with reduced clinker content. Despite these advances, several critical gaps remain. A deeper understanding of the dynamic evolution, migration, and in-situ behavior of these nanocomposites within the complex chemical environment of hydrating cement paste is urgently needed. Future research should focus on imparting multifunctionality to these materials, such as self-healing or responsive properties, to create smarter and more durable concrete. The development of cost-effective, scalable, and sustainable synthesis methods, potentially utilizing industrial by-products, is essential for widespread adoption. Leveraging advanced computational tools like molecular dynamics simulations and machine learning can be instrumental in accelerating the rational design and optimization of the next generation of these high-performance nanomaterials.

Despite significant achievements, several challenges remain in understanding and optimizing nanofiller-modified interfaces. First, the existing characterization techniques are limited in their ability to capture the dynamic evolution of interfacial structures at high spatial and temporal resolution. Most methods provide only static, two-dimensional information, making it difficult to fully understand multi-scale and multi-physics processes. Second, the inherent heterogeneity and discontinuity of interfaces complicate quantitative modeling. The existing models often describe average behavior, but fail to capture local weak zones or nanoscale force transfer mechanisms. Third, the introduction of multifunctional nanofillers increases the complexity of multi-field coupling (i.e., mechanical, thermal, chemical, and electrical), posing challenges for unified theoretical frameworks. Finally, the large-scale engineering application of nanomodified interfaces is hindered by some issues such as nanofiller dispersion, cost, and performance stability under complex service conditions.

Future research should focus on several key directions. Advanced characterization techniques with a high spatiotemporal resolution, such as synchrotron radiation-based imaging and X-ray computed tomography, should be developed to enable real-time tracking of interfacial evolution. The integration of artificial intelligence and machine learning can facilitate high-throughput data analysis and predictive modeling, enabling a quantitative design of interfacial properties. Multi-scale theoretical frameworks that link material composition, microstructure, and macroscopic performance are needed to achieve accurate prediction and optimization. Also, efforts should be made to translate laboratory findings into practical engineering applications, particularly in emerging areas such as 3D-printed concrete, recycled concrete, concrete repair, and self-healing cement-based materials.

In summary, nanomodification is demonstrated to effectively tailor interfaces in cement-based materials and their structures, while the enrichment effect and nano-core effect is proposed to clarify the underlying mechanisms. These advances provide a foundation for mitigating the inherent weakness of interfaces. Despite these advances, some challenges remain in terms of characterization, quantitative modeling, and large-scale application. Nevertheless, continued progress in nanotechnology, multi-scale analysis, and intelligent design is expected to enable the rational design and engineering of high-performance, durable, and multifunctional cement-based materials and their structures.

With the increasing depth of oil and gas exploration, high-temperature and high-pressure conditions become common in deep and ultra-deep wells. Under such harsh environments, the long-term integrity of wellbore cement is frequently compromised due to the strength retrogression, posing serious risks to zonal isolation and production safety. Although silica sand is widely used to mitigate strength degradation via modifying the Ca/Si ratio of hydration products, recent studies show that significant strength loss still occurs at ultra-high temperatures.

Previous studies focused on curing regimes involving low-temperature pre-curing followed by high-temperature exposure, which mainly represent upper wellbore conditions. However, in deeper sections of high-temperature wells, cement typically sets and cures directly at elevated temperatures, resulting in more severe degradation. In addition, low-density cement is widely applied in cementing operations, its long-term performance under such conditions remains insufficiently understood, particularly beyond short-term curing periods. This study was to investigate the long-term performance evolution and underlying mechanisms of low-density sand-added oil well cement under different high-temperature conditions, providing a guidance for the design of durable cement systems for deep well applications.

Six low-density cement slurry formulations with a target density of 1.6 g/cm³ were designed, incorporating silica sand, silica fume, and hollow glass microspheres. Two curing regimes were adopted to simulate different downhole environments, i.e., (1) direct curing at 180 ℃ to represent high-temperature deep well conditions, and (2) curing at 80 ℃ for 2 d and then long-term curing at 180 ℃ to simulate upper wellbore conditions. The long-term performance of cement samples was evaluated after curing at 180 ℃ for 2, 30 d, and 90 d, respectively. The compressive strength, Young's modulus, and permeability were measured to assess macroscopic properties. The microstructural and mineralogical evolution was characterized by mercury intrusion porosimetry (MIP), X-ray diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM), enabling a comprehensive analysis of pore structure development and hydration product transformation.

The results indicate that curing conditions have a decisive influence on the long-term performance of low-density cement systems. Under direct high-temperature curing at 180 ℃, all formulations exhibit severe strength retrogression. The compressive strength of silica sand-based systems remains approximately 28 MPa within 30 d, but decreased to below 10 MPa after 90 d. The incorporation of hollow glass microspheres significantly enhances the early strength (i.e., up to 45 MPa at 2 d). However, these systems experience a rapid deterioration, with strength nearly disappearing after 30 d. In contrast, the samples subjected to low-temperature pre-curing and followed by high-temperature exposure show significantly improved stability. For formulations without hollow glass microspheres, the compressive strength remains stable or slightly increases for 90 d. However, the systems containing hollow glass microspheres still exhibit a noticeable strength reduction, indicating their limited suitability for high-temperature applications. The evolution of Young's modulus and permeability is consistent with the strength results. Under direct high-temperature curing, Young's modulus decreases markedly, while permeability increases in orders of magnitude, indicating severe degradation of structural integrity. Conversely, under low-temperature pre-curing conditions, the parameters both remain relatively stable, reflecting an improved durability. The microstructural analysis reveals that pore structure coarsening plays a key role in the performance degradation. Under direct high-temperature curing, the median pore size increases significantly from tens to hundreds of nanometers, accompanied by a transformation from harmless pores to harmful large pores. In contrast, the samples subjected to low-temperature pre-curing exhibit slower pore coarsening and more stable pore size distributions. The mineralogical evolution further explains the observed macroscopic behavior. Under direct high-temperature curing, beneficial amorphous hydration products and tobermorite gradually transform into more crystalline phases such as xonotlite, leading to the strength loss. The thermogravimetric analysis confirms significant changes in decomposition peaks, indicating alterations in hydration product composition. In contrast, under low-temperature pre-curing conditions, the content of amorphous phases and tobermorite remains relatively stable, contributing to sustained mechanical performance. The SEM images show that hollow glass microspheres progressively react and disappear under prolonged high-temperature exposure, leaving large voids that significantly deteriorate the microstructure. Although these microspheres enhance the early strength, their long-term effect is detrimental due to the pore enlargement and structural weakening.

This study demonstrated that curing conditions critically affected the long-term performance of low-density sand-added oil well cement. Direct high-temperature curing led to severe strength retrogression, pore structure coarsening, and unfavorable phase transformations, whereas low-temperature pre-curing significantly improved long-term stability. Hollow glass microspheres were effective in enhancing early strength but are not suitable for high-temperature applications due to their negative impact on long-term durability. The stability of hydration products, particularly amorphous phases and tobermorite, could be identified as a key factor governing strength retention. These findings could provide important insights into the design of durable cement systems for high-temperature oil and gas wells and highlight the necessity of considering both curing conditions and material composition in practical applications.

Low-temperature co-fired ceramic (LTCC) technology becomes a cornerstone in the fabrication of high-frequency, high-density microelectronic devices. However, a critical challenge lies in a thermal expansion mismatch between conventional LTCC substrates (typically <7 × 10^-6 ℃^-1) and printed circuit boards (PCBs, 12-16 × 10^-6 ℃^-1), leading to interfacial delamination and compromised reliability. To address this issue, developing LTCC materials with high and linear thermal expansion coefficients is essential. Among some potential candidates, BaO-B₂O₃-SiO₂ glass-ceramics stand out due to their tunable properties and relatively high thermal expansion. Nevertheless, achieving dense sintering at < 900 ℃, while maintaining a high thermal expansion coefficient (>11 × 10^-6 ℃^-1), remains a key obstacle. This study was to investigate the synergistic effects of incorporating CaO and SrO into BaO-B₂O₃-SiO₂ glass-ceramics on the sintering behavior, crystallization characteristics, and overall performance for LTCC applications.

Four glass compositions were designed based on the BaO-B₂O₃-SiO₂ system at different additions of CaO and SrO (in mole fraction), i.e., BBS1 (baseline), BBS2 (with 10% CaO), BBS3 (with 10% SrO), and BBS4 (with 5% CaO and 5% SrO). Raw materials including BaCO₃, CaCO₃, SrCO₃, H₃BO₃, and SiO₂ were melted at 1400 ℃ for 2 h, quenched, and ground into powders with a consistent particle size (D₅₀ ≈ 5 μm). The powders were pressed into pellets and bars, then sintered at 800 ℃ for 20 min. The sintering behavior was analyzed by high-temperature microscopy and dilatometry. The glass transition (T_g) and crystallization (T_c) temperatures were determined by differential scanning calorimetry (DSC). The phase identification and crystallinity were evaluated by X-ray diffraction (XRD), and the microstructural features were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. The thermal expansion, density, dielectric properties, flexural strength, and hardness were measured to assess the performance of the sintered glass-ceramics.

The introduction of CaO and SrO significantly lowers the onset (T_fs) and maximum shrinkage (T_ms) temperatures, with SrO having a more pronounced effect. For instance, T_fs decreases from 720 ℃ (BBS1) to 654 ℃ (BBS3), and T_ms decreases from 794 ℃ to 761 ℃. This indicates enhanced sintering kinetics due to the larger ionic radius and higher polarizability of Sr²⁺, which facilitates atomic mobility and reduces activation energy. The results of DSC reveal that the addition of CaO and SrO also decreases T_g and T_c, with SrO again exhibiting a greater influence. The ΔT (T_c-T_g) value, which reflects the processing window for sintering, is increased in SrO-containing samples, indicating an improved sinter-ability.

The XRD patterns show that the baseline sample (BBS1) primarily crystallizes into Ba₂Si₄O₁₀, while CaO addition (BBS2) promotes the formation of Ba₅(Si₈O₂₁), and SrO addition (BBS3) and co-addition (BBS4) favor forming Ba₂Si₃O₈. The crystallinity increases due to CaO and SrO incorporation, reaching a maximum of 77.76% in BBS2, indicating that CaO is more effective in promoting crystallization due to its smaller ionic radius and higher field strength, which enhances network disruption and nucleation. The Raman spectra confirm a structural transformation from [BO₃] to [BO₄] units, indicating a more connected and dense glass network.

The microstructural analysiss reveals that the baseline sample has a porous structure with dispersed spherical crystals. In contrast, CaO and SrO additions lead to denser microstructures with interlocked crystal morphologies. Particularly, BBS4 exhibits a uniform distribution of plate-like Ba₂Si₃O₈ crystals and reduced porosity, contributing to its superior mechanical properties.

Thermal expansion coefficients (30-300 ℃) range from 11.52 × 10^-6 ℃^-1 to 12.43 × 10^-6 ℃^-1, with BBS4 showing a balanced value of 11.94 × 10^-6 ℃^-1. The slight decrease compared to the baseline is attributed to the increased [BO₄] content and denser structure. The dielectric constants at 1 MHz vary between 6.51 and 7.82, with BBS3 showing the maximum value due to its high-polarizability Sr²⁺ and Ba₂Si₃O₈ phase. The flexural strength and hardness are significantly improved in CaO- and SrO-modified samples, with BBS4 achieving the maximum values (i.e., 124.36 MPa and 953.88 HV). These enhancements are attributed to increased crystallinity, reduced porosity, and optimized crystal interlocking.

This study demonstrated that the co-incorporation of CaO and SrO into BaO-B₂O₃-SiO₂ lass-ceramics effectively modulated their sintering and crystallization behaviors, enabling dense sintering at 800 ℃. SrO played a dominant role in lowering sintering temperatures, while CaO was more effective in promoting crystallization. The synergistic effect of both oxides led to a glass-ceramic with a high thermal expansion coefficient (i.e., 11.94 × 10^-6 ℃^-1), excellent mechanical strength (i.e., 124.36 MPa), and favorable dielectric properties (i.e., 8.71 at 1 MHz), making it highly suitable for LTCC applications. The findings could provide a promising pathway for developing high-performance, low-temperature sintering glass-ceramics with tailored thermal and mechanical properties.

COFs demonstrate a significant potential as advanced sulfur host materials in Li-S batteries, effectively mitigating the polysulfide shuttle effect as a major bottleneck to commercialization through their tunable pore structures, high surface areas, and designable functional sites. This review systematically outlines the development of COF-based materials in Li-S battery cathodes, from early physical confinement strategies to recent advances involving heteroatom doping, multidimensional architectures, flexible frameworks, and conductive composites. These approaches can collectively enhance sulfur utilization, improve reaction kinetics, and increase cycling stability.

Despite these promising developments, several challenges remain for the practical application of COF-based cathodes. The key issues include the limited intrinsic conductivity of most COFs, difficulties in maintaining crystallinity during large-scale synthesis, insufficient chemical stability under prolonged cycling, and high manufacturing costs. Moreover, optimizing electrolyte/sulfur ratios and interface engineering between COFs and sulfur are critical for improving electrochemical performance.

Future research should prioritize 1) enhancing the electronic and ionic conductivity of COFs through structural design and hybridization with conductive substrates; 2) developing scalable and eco-friendly synthesis methods to facilitate commercial adoption; 3) designing COFs with high sulfur loading capacity and strong polysulfide adsorption; 4) improving chemical and mechanical stability under operating conditions; and 5) employing advanced in-situ characterization techniques to elucidate ion transport and reaction mechanisms. With continued innovation in material design and processing, COF-based sulfur hosts are expected to play a vital role in realizing high-energy, long-lasting, and commercially viable Li-S batteries.

Ultra-high performance concrete (UHPC) has emerged as a critical material for achieving structural lightweight design and enhanced longevity in civil engineering due to its exceptional mechanical properties and durability. The optimization of UHPC performance relies on particle gradation design for constructing dense packing systems and interfacial transition zone (ITZ) regulation to enhance matrix continuity. However, traditional UHPC formulations depend on resource-intensive materials such as river sand and silica fume, while existing particle packing theories predominantly assume ideal spherical particles, lacking systematic understanding of the coupling mechanisms associated with natural aggregate complex morphological characteristics. Volcanic rock, characterized by rich active substances and irregular angular morphology, offers a novel material pathway for UHPC performance regulation through multi-scale morphological control when processed into aggregates (replacing standard sand) and mineral admixtures (volcanic rock powder replacing cement).

The study systematically investigated the physicochemical synergistic enhancement mechanisms of volcanic rock materials in UHPC through comprehensive experimental analysis. Volcanic rock aggregates (VRA) with varying replacement ratios (0%-100%) of standard sand and volcanic rock powder (VRP) with different substitution levels (0%-30%) of cement were incorporated into UHPC mixtures. The modified Andreasen-Andersen model guided the mix design optimization. Fresh properties were evaluated through flow spread tests and wet packing density measurements according to the established method. Mechanical performance was assessed via compressive and flexural strength tests at 3, 7 d, and 28 d. Accelerated ASR expansion was measured using mortar bar method. Three-dimensional structural analysis using X-ray computed tomography (CT) characterized macropore structure and fiber orientation distribution. Hydration processes were monitored using isothermal calorimetry, while microstructural features were examined through scanning electron microscopy (SEM) and nanoindentation testing.

The workability and wet packing density of fresh UHPC exhibited an initial increase followed by a decrease with increasing VRA replacement ratios, achieving optimal values at 50% replacement. Flow spread increased from 122 mm to 133.5 mm before declining to 128.5 mm, while wet packing density improved from 0.803 to 0.819 before decreasing to 0.808. VRP substitution demonstrated a monotonic increasing trend in flowability, with wet packing density peaking at 10% replacement. This phenomenon was attributed to the friction network regulation mechanism of "angular-rounded" particle interactions and particle gradation optimization by volcanic rock powder.

Mechanical performance analysis revealed that 75% VRA replacement maximized flexural strength across all curing ages, while 20% VRP substitution yielded optimal 28 d compressive strength. X-ray CT analysis demonstrated that 50% VRA replacement minimized total porosity, with large pores (10⁷-10⁸ μm³) systematically decreasing as VRA content increased. The angular morphology of volcanic rock aggregates promoted preferential horizontal alignment of steel fibers, with significant clustering in low-angle regions (0°-30°), thereby substantially enhancing UHPC flexural performance. VRP optimized pore distribution structure through pozzolanic reactions filling microscopic pores at appropriate replacement levels, achieving a dynamic balance between secondary hydration benefits and cement dilution effects. Nanoindentation results confirmed that VRA-matrix interfacial transition zones exhibited superior mechanical properties compared to those of standard sand interfaces, with elastic modulus improvements of approximately 49.7%.

Calorimetric analysis revealed that VRA incorporation increased 3 d cumulative heat release compared to standard sand groups, attributed to surface active substances and enhanced interfacial contact promoting early cement hydration. VRP exhibited delayed hydration kinetics with peak heat release occurring at later ages, with 20% replacement achieving the highest 3 d cumulative heat release due to optimized pozzolanic reaction contributions, while higher dosages (30%) inhibited hydration processes due to lower reactivity of VRP and dilution effect.

This study established that volcanic rock materials effectively enhance UHPC performance through physicochemical synergistic mechanisms, with optimal performance achieved at 50%-75% VRA replacement and 20% VRP substitution. The angular morphology of volcanic rock aggregates improved fiber orientation distribution and mechanical interlocking with the cement matrix, while volcanic rock powder optimized particle packing efficiency and promoted secondary hydration reactions. The enhancement mechanisms originate from three synergistic factors: superior intrinsic mechanical properties comparable to standard sand, angular particle morphology creating three-dimensional mechanical interlocking structures that optimize packing efficiency, and surface active components promoting pozzolanic reactions that densify interfacial microstructure. These findings provide experimental evidence for extending particle packing theory beyond conventional spherical particle assumptions, establishing critical relationships between “morphological characteristics-packing efficiency-interface performance” and macroscopic UHPC properties for complex-shaped aggregates design.

Achieving the "carbon peaking and carbon neutrality" targets requires efficient energy storage technologies. Supercapacitors with the high power density, rapid charge-discharge, and long cycle life show a great potential in renewable energy, electric vehicles, and smart grids. However, their low energy density limits wider applications. Transition metal oxides such as RuO₂ and MnO₂ are promising electrode materials due to their reversible faradaic reactions and high theoretical capacitance. Single-component oxides suffer from insufficient active sites and structural degradation, impairing rate capability and stability. Multi-metal oxide strategies leverage synergistic effects to optimize lattice, charge distribution, morphology, and performance. Cobalt-based oxides provide abundant Co²⁺/Co³⁺ redox pairs, manganese adds multiple valence states and structural buffering, while zinc enhances conductivity and stability. Nevertheless, low conductivity and poor kinetics persist. Oxygen vacancies improve conductivity, tune band structure, and create active sites via reducing bandgap and accelerating kinetics. In this work, oxygen-vacancy-rich Ov-Co₃Zn₁Mn_0.5O₅ nanoflowers were synthesized via hydrothermal-annealing-NaBH₄ reduction and multi-metal synergy and defect engineering to optimize morphology and electronic structure. This approach could validate the synergistic benefits and offer a strategy for high-performance transition metal oxide supercapacitor electrodes.

All chemicals were of analytical grade and used as received. Nickel foam substrates (2 cm × 3 cm) were pretreated in HCl solution of 3 mol/L under ultrasonication for 5 min to remove surface oxides and thoroughly rinsed with deionized water. For the synthesis of Co₃Zn₁Mn_0.5O₅, stoichiometric amounts of Co(CH₃COO)₂·6H₂O (3 mmol), Zn(CH₃COO)₂·H₂O (1 mmol), MnC₄H₆O₄·4H₂O (0.5 mmol), and urea (0.2 g) were dissolved in deionized water of 60 mL to form a homogeneous precursor solution. The solution together with the pretreated nickel foam was sealed in a 100 mL Teflon-lined autoclave and maintained at 120 ℃ for 6 h. After natural cooling, the nickel foam-supported precursor was washed, dried, and subsequently annealed in air at 400 ℃ for 2 h, yielding Co₃Zn₁Mn_0.5O₅ with a mass loading of 1.12 mg·cm^-2. For comparison, binary and other ternary oxides (i.e., Co₃Zn₁O₄, Co₃Mn_0.5O₄, Zn₁Mn_0.5O₂, Co₂Zn₁Mn_0.5O₄, and Co₄Zn₁Mn_0.5O₆) were prepared under the same conditions above. Oxygen vacancies were introduced via immersing the annealed Co₃Zn₁Mn_0.5O₅ in NaBH₄ solution for 12 min, followed by vacuum drying at 80 ℃ for 2 h to obtain Ov-Co₃Zn₁Mn_0.5O₅ (a mass loading of 1.02 mg·cm^-2). Comparative samples Ov-Co₂Zn₁Mn_0.5O₄ and Ov-Co₄Zn₁Mn_0.5O₆ were also prepared.

The morphology was determined by field-emission scanning electron microscopy (S-4800, Hitachi Co., Japan) and transmission electron microscopy (JEM-2100F, JEOL Co., Japan). The rystal structure was identified by X-ray diffraction (D/MAX-2500, Rigaku Co., Japan, Cu K_α, λ = 0.154156 nm). The surface chemical states and valence distributions were analyzed by X-ray photoelectron spectroscopy (K-Alpha, Thermo Co., USA). The oxygen vacancy concentration was quantified by electron paramagnetic resonance (EMXplus, Bruker Co., Germany) and thermogravimetric analysis (TG 209 F3 Netzsch Co., Germany). The electrochemical measurements were conducted in a three-electrode configuration with 6 mol/L KOH electrolyte using a CHI760e workstation. The cyclic voltammetry and galvanostatic charge-discharge within 0-0.5 V at different scan rates of 10-100 mV·s^-1 and various current densities were detremined. The electrochemical impedance spectroscopy was performed on a BioLogic SP-150 workstation. The density functional theory calculations were carried out by a software named Materials Studio package using the projector-augmented wave method.

The three-step hydrothermal-annealing-NaBH₄ reduction process yields uniform flower-like Ov-Co₃Zn₁Mn_0.5O₅ nanoflowers directly grown on nickel foam. The SEM images reveal that the binary oxides display irregular nanosheets or nanowires, whereas the ternary Co₃Zn₁Mn_0.5O₅ forms large-sized nanosheets assembled into a loose porous flower-like morphology that provides abundant redox active sites. After NaBH₄ treatment, the overall morphology is preserved, while porosity is markedly increased. The TEM images confirm the porous nanosheet structure in the both samples, with Co₃Zn₁Mn_0.5O₅ exhibiting more mesopores and atomic-level defects evidenced by disordered lattice fringes. The HRTEM images display lattice spacings of 0.202 nm and 0.156 nm, corresponding to the plane (400) of MnCo₂O_4.5 and the plane (511) of ZnCo₂O₄. The EDS mapping shows a homogeneous distribution of elements Co, Zn, Mn and O, and Mn content is lower than the nominal ratio. The XRD patterns confirm the coexistence of cubic spinel MnCo₂O_4.5 and ZnCo₂O₄ phases in all the samples, and Ov-Co₃Zn₁Mn_0.5O₅ shows a higher crystallinity. The TGA and EPR unambiguously verify abundant oxygen vacancies. The XPS analysis reveals positive shifts in Co 2p, Mn 2p, Zn 2p, and O 1s binding energies after reduction, accompanied by increased proportions of low-valence Co²⁺, Mn³⁺, and a larger O_V peak area, confirming mixed-valence states and defect formation. The results of electrochemical tests demonstrate clear synergistic effects. The CV curves at 10 mV·s^-1 exhibit the largest integrated area for the ternary composition. The oxygen-vacancy introduction further enlarges the area due to more active sites and lowered OH^- intercalation barrier. The b-values of 0.70 and 0.77 indicate combined diffusion and pseudocapacitive contributions. The GCD measurements deliver an ultrahigh specific capacitance of 1509.8 F·g^-1 at 2 A·g^-1 and retain 809.1 F·g^-1 at 20 A·g^-1, demonstrating an excellent rate capability. The assembled Ov-Co₃Zn₁Mn_0.5O₅//AC asymmetric supercapacitor maintains stable CV shapes up to 100 mV·s^-1 within a 1.6 V window, achieves a high energy density of 53.8 W·h·kg^-1 at 750 W·kg^-1, and retains 76.4% capacitance after 5000 cycles with the Coulombic efficiency of 99%. The DFT calculations reveal that oxygen vacancies eliminate the original 0.098 eV bandgap, introduce mid-gap defect states, increase carrier concentration and facilitate electron hopping between low-valence Co²⁺and Mn³⁺ sites, thereby significantly enhancing conductivity and redox kinetics.

The flower-like Ov-Co₃Zn₁Mn_0.5O₅ with rich oxygen vacancies was successfully synthesized by a facile hydrothermal-annealing-NaBH₄ reduction method. The unique nanosheets-assembled nanoflower structure could expose abundant active sites and enhance redox kinetics. The introduction of oxygen vacancies regulated the electronic structure, improved conductivity, and induced low-valence Co²⁺ and intermediate Mn³⁺ to promote redox reactions. The Ov-Co₃Zn₁Mn_0.5O₅ electrode delivered a high specific capacitance of 1509.8 F·g^-1 at 2 A·g^-1 with the excellent rate performance. The assembled asymmetric supercapacitor achieved 53.8 W·h·kg^-1 energy density at 750 W·kg^-1 and retained 76.4% of its initial capacitance after 5000 cycles with the Coulombic efficiency of 99%. This work could demonstrate the synergistic optimization of multi-metal composition and oxygen vacancy engineering for advanced transition metal oxide electrodes in supercapacitors.

Lithium-ion batteries (LIBs) with a high energy density are critical for advancing electric vehicles and renewable energy storage systems. Silicon oxycarbide (SiOC) anode materials emerge as promising candidates due to their high cycling stability, suitable operating potential, low cost, and environmental compatibility. Unlike conventional silicon anodes that suffer from severe volume expansion (i.e., >300%), SiOC materials benefit from the uniform distribution of silicon and carbon in an atomic scale, forming protective Li₂O and lithium silicate layers during initial lithiation that mitigate volume changes. However, a practical implementation of SiOC anodes remains challenging due to their intrinsically low electronic/ionic conductivity and significant volumetric changes during cycling, leading to electrode pulverization, loss of electrical contact, and excessive solid-electrolyte interphase (SEI) growth. In this study, a novel synthesis strategy was proposed to create SiOC anodes with engineered yolk-shell and porous architectures that could simultaneously optimize structural stability, ionic/electronic transport, and interfacial properties.

This work employed a meticulously controlled sol-gel process followed by selective etching under mild alkaline conditions to fabricate SiOC anode materials with distinctive architectures. A yolk-shell structured material (YS@C) was prepared by a sequential addition approach via incorporating 1,4-bis(triethoxysilyl)benzene (BTEB) to form the core, and then adding tetraethoxysilane (TEOS) to create the shell. For the porous material (P@C), BTEB and TEOS were introduced simultaneously. The structures both underwent selective etching with a 2.4 mol/L Na₂CO₃ solution, removing portions of the inorganic silica, while preserving the organic-inorganic hybrid framework. Subsequently, resorcinol-formaldehyde resin was coated onto the etched structures and carbonized in 10% H₂/Ar atmosphere at 800 ℃ to form conductive carbon layers. The structural and chemical properties were determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and BET surface area analysis. The electrochemical performance was evaluated through cyclic voltammetry, galvanostatic charge-discharge testing, rate capability analysis, long-term cycling, and impedance spectroscopy, respectively.

The mild alkaline etching strategy produces monodisperse YS@C particles (with the sizes of 250-270 nm) featuring a distinctive yolk-shell structure with an intermediate void space, and P@C particles (with the sizes of 320-350 nm) with uniformly distribute internal pores. The structural analyses reveals amorphous characteristics with carbon contents of 75.51% for YS@C and 68.2% for P@C. The specific surface areas measured are 17.041 m²/g for YS@C and 27.458 m²/g for P@C, with the average pore sizes of 2.371 nm and 2.561 nm, respectively. The XPS analysis demonstrates different silicon valence states, with the average values of 2.796 9 for YS@C and 2.999 2 for P@C, indicating varying degrees of silicon oxidation that affect the electrochemical behavior.

In electrochemical testing, YS@C delivers the superior performance with an initial Coulombic efficiency of 55%, compared to 49% for P@C. Most significantly, YS@C maintains an exceptional cycling stability with specific capacities of 453 mA·h·g^-1 after 550 cycles at 0.5 A/g and 361 mA·h·g^-1 after 1000 cycles at 1 A/g, with the Coulombic efficiency consistently of > 99% after the sixth cycle. The kinetic analyses reveals the superior Li⁺ diffusion coefficient and remarkable pseudocapacitive contribution of YS@C (i.e., 82.2% at 2.0 mV/s) due to its shortened ion diffusion pathways. The post-cycling SEM examination confirms the structural integrity after 300 cycles of YS@C, while P@C exhibits significant cracking and degradation.

This research demonstrated that the gradient composition and hierarchical architecture of YS@C, featuring a high-capacity siloxane-rich core, intermediate void space, and protective carbon/SiOx shell, could collectively address the fundamental limitations of SiOC anode materials. The internal void space effectively accommodated volume expansion during lithiation/delithiation, while the carbon-rich shell enhanced conductivity and minimized detrimental side reactions with the electrolyte. The mild alkaline etching approach presented could offer a gentle yet effective method for engineering complex architectures without damaging the organic components critical for performance. The exceptional electrochemical performance of YS@C, particularly its unprecedented cycling stability at high current densities, could establishe a benchmark for SiOC-based anodes. This work could advance the development of high-performance lithium-ion battery anodes and provide valuable design principles for engineering gradient-structured materials for various energy storage applications. Future research could focus on scaling this synthesis approach and exploring its applicability to other conversion/alloying-type electrode materials requiring volume change accommodation.

As functional ceramics are increasingly required for more advanced device platforms and harsher service environments, the demand for even higher levels of performance continues to grow. At the core of this challenge lies the persistent coexistence of multi-objective trade-offs and multi-scale problems. Therefore, we systematically summarize the paradigm shifts and representative advances brought about by the introduction of AI into materials research. We outline the broader landscape of AI-enabled functional ceramics research from the perspectives of data, model and application, and further summarize the key strategies and transformative pathways for this field through three major directions: intelligent inverse design, cross-scale intelligent computation and large-language-model-driven research platforms. As data infrastructure, model capability and closed-loop deployment technologies continue to mature, artificial intelligence is poised to evolve from an auxiliary analytical tool into a systematic design framework that connects knowledge, computation, decision and experimental execution, thereby advancing functional ceramics research towards a more efficient and scalable paradigm.