In transition towards a decarbonized energy system globally, hydrogen plays a crucial role as a zero carbon energy carrier. In this context, solid oxide electrolysis cell (SOEC) technology with its advantages in high-temperature operation significantly reduces material costs and improves overall system energy efficiency, compared to low-temperature solutions such as alkaline and proton exchange membrane electrolysis. SOEC system adopts a non-precious metal ceramic structure. When operating at 650-1000 ℃, electrochemical kinetics acceleration mechanism achieves a conversion efficiency of > 80%, providing a feasible approach to reduce cost of green hydrogen leveling. The existing domestic demonstration projects are limited to a scale of tens to hundreds of kilowatts, and the commercial implementation needs to break through bottleneck of "three highs and one low", thus increasing power density of fuel cell stack, extending its service life, and optimizing system integration, while reducing assets and operation and maintenance costs. Solving these obstacles requires collaborative efforts in three major fields, and innovation in materials and structures must break through conventional design framework of electrodes, electrolytes, and sealing glass. With precise microstructure design and interface stress control, system can maintain a high current density of 2 A·cm^-2, while controlling degradation rate at 1 mV per thousand hours, significantly extending lifespan of battery pack. Multi-energy coupling optimization is crucial, which requires integrating the SOEC with industrial waste heat and renewable resources, thus utilizing low-grade thermal energy (i.e., 200-300 ℃), efficiently offsetting internal heating demand, reducing external electricity consumption by approximately 30%, and comprehensively improving energy utilization efficiency. For those localized supply chains, establishing a complete domestic production capacity from precursor powder to single cell manufacturing, stacking and assembly to system integration is particularly crucial. The goal is to control stacking cost at RMB 2500 per kW and achieve an operating life of 5×10⁴ h, laying a foundation for large-scale applications. At present, although the SOEC has significant energy efficiency advantages, its promotion and application still face multiple constraints, i.e., gradual decay of oxygen electrodes under high temperature and high vapor partial pressure, mechanical and electrochemical damage caused by power fluctuations, and daunting initial capital investment. Subsequent exploration should focus on preparing new electrode materials with a higher stability, establishing flexible thermoelectric synergistic regulation mechanisms to adapt to fluctuating renewable energy, and promoting standardization and cost reduction and efficiency improvement throughout entire industry chain. The cost of photovoltaic and wind power continues to decrease, coupled with increasing demand for green hydrogen in chemical and metallurgical fields. Solid oxide electrolysis cell technology is expected to be widely applied in "electricity hydrogen ammonia/methanol" integrated system, distributed energy system, and sustainable refining scenarios. This technology will undoubtedly become a key pillar technology supporting the dual carbon goals in China.

Cement production accounts for approximately 12% of China's total CO₂ emissions, having a significant challenge to achieving the national "dual carbon goals". Carbon capture, utilization, and storage (CCUS) represent a pivotal innovative technology for mitigating these emissions. However, conventional amine-based CO₂ capture requires an energy-intensive high-temperature desorption, hindering its industrial implementation in cement plants. Also, the limited utilization pathways for captured CO₂ pose another challenge for cement CCUS. Diethanolamine (DEA) offers a promising solution as it functions both as a CO₂ absorber and a cement additive. This dual capability enables a potential carbonation utilization of CO₂ absorbed DEA solutions without requiring the desorption step within cementitious systems. This study was thus to investigate the effect of CO₂-absorbed diethanolamine (DEAC) on the early hydration behavior and strength development of cementitious systems. The findings could propose a novel approach for low-energy CO₂ capture coupled with efficient in-situ utilization within cement industry.

Cement mortars with a water-to-cement ratio (W/C) of 0.50 were prepared with P·I 42.5 Portland cement (GB 8076) and ISO standard sand. The specimens were designated as REF, D0.1%C0%, D0.1%C0.02%, D1.0%C0%, and D1.0%C0.22%, respectively. DEA and its equivalent CO₂ admixture were added as percentages of cement mass. All associated cement paste mixtures were prepared at a W/C ratio of 0.3. DEAC was prepared by continuously bubbling CO₂ gas (≥99% purity) at a flow rate of 200 mL/min through a 5 mol/L DEA solution maintained at 40 ℃ until saturation was achieved. An eight-channel microcalorimeter recorded the hydration heat of cement paste specimens at 25 ℃ for 72 h. The phase composition of hardened cement pastes was determined by X-ray diffraction (XRD). The contents of bound water, CH, and CaCO₃ were analyzed by thermogravimetric analysis (TGA). The cumulative porosity and pore size distribution of hardened paste samples at 7 d were characterized by mercury intrusion porosimetry (MIP). The compressive strength was measured on mortar specimens at 1, 3 d and 7 d of curing in accordance with the standard GB/T 17671.

The hydration calorimetry results demonstrate that D0.1%C0.02% and D0.1%C0% both accelerate the hydration rate of silicate phases, as evidenced by an increased second exothermic peak rate, while leaving the induction period duration unaffected. Conversely, D1.0%C0% and D1.0%C0.22% significantly reduce the second exothermic peak rate. D1.0%C0.22% extends the hydration induction period to 240 min, while D1.0%C0% has a negligible effect on its duration. The XRD patterns and TG analyses reveal that the impact of DEAC on the cement hydration depends critically on its specific DEA and CO₂ dosage. At a low dosage (i.e., D0.1%C0.02%), a mild carbonation promotes a concurrent hydration of silicate and aluminate phases. However, a high dosage (i.e., D1.0%C0.22%) substantially inhibits early hydration of silicates. The MIP results indicate that DEAC and DEA both refine the pore structure of hardened cement paste. The pores below 20 nm are significantly reduced in D0.1%C0% and D0.1%C0.02% systems, aligning with their enhanced early hydration kinetics. This refinement also occurres in D1.0%C0% and D1.0%C0.22% systems despite inhibited silicate hydration. The results of compressive strength tests show that D0.1%C0.02% and D0.1%C0% can enhance mortar strengths at 1, 3 d, and 7 d, respectley. The strengths of D0.1%C0.02% systems can be increased by 8.4%, 10.2%, and 16.8% at these ages, respectively, primarily due to the DEA component with the weak carbonation contributing minimal additional enhancement. The 3-day and 7-day strengths of D1.0%C0.22% and D1.0%C0% systems both are increased (more significantly in the carbonated system), indicating a synergistic hydration-carbonation effect. However, the 1-day strength of D1.0%C0.22% system drastically is reduced by 52.2%, with silicates hydration inhibition by D1.0%C0% identified as a primary factor underpinning early strength reduction. According to the analysis of bound water content, calcium hydroxide (CH) content, porosity, and compressive strength relationships, a linear correlation between CH content and mortar strength is proposed. This demonstrates that silicate phase hydration kinetics can be modulated differently by DEAC and DEA formulations-fundamentally governed compressive strength development.

The addition of 0.1%DEA with 0.02% CO₂ (D0.1%C0.02%) as DEAC enhanced the flexural and compressive strengths of cement mortar at 1, 3 d, and 7 d. In contrast, the addition of 1.0% DEA with 0.22% CO₂ (D1.0%C0.22%) significantly reduced the 1-day strength. In D0.1%C0.02% system, the CO₂ component reacted with dissolved Ca²⁺ released from cement minerals to precipitate CaCO₃. This reaction promoted cement hydration, refined the pore structure of the hardened paste by reducing the volume of harmful pores, and facilitated a synergistic enhancement of hydration and carbonation. D1.0%C0.22% addition significantly retarded cement hydration within the first 24 h, primarily by inhibiting the dissolution of silicate phases and extending the induction period, leading to the reduced early strength. Although carbonation exacerbated the retardation of silicate phase hydration via DEA interaction, the hydration process recovered normal kinetics after 7 d.

High-temperature vibration sensors are indispensable key components for the health detection of core equipment in fields such as aerospace and nuclear energy. The BiScO₃-PbTiO₃(BS-PT) system has attracted much attention due to its high Curie temperature (T_C≈450 ℃) and excellent piezoelectricity (d₃₃≈450 pC/N). However, the poor insulation properties of this material hinder its application in high-temperature vibration sensors because high electrical resistivity (ρ) and a long time constant (τ) are critical to prevent thermal runaway and ensure signal integrity. Manganese (Mn) doping is a commonly used modification method for piezoelectric ceramics. Previous studies on Mn-doped BS-PT were controversial regarding the valence state distribution and substitution positions of Mn ions, which could not be conducive to the design of high-temperature piezoelectric ceramics with the collaborative optimization of multiple electrical parameters. Therefore, this work was to clarify the defect chemical mechanism associated with manganese doping through refined structural characterization combined with electrical performance analysis, and to obtain the modified BS-PT piezoelectric ceramic components suitable for high-temperature vibration sensors.

0.365BiScO₃-0.635PbTiO₃-x% MnO₂ (BSPT-x% MnO₂, x=0.00, 0.01, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75, 2.00) ceramics were synthesized by a conventional solid-state reaction method. The powders were firstly calcined at 800 ℃ for 2 h and then sintered at 1050 ℃ for 2 h. The phase composition was analyzed by X-ray diffraction (XRD). The rietveld refinements were performed using a software named GSAS. The microstructure and elemental distribution were examined by scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS). The average grain size was estimated by a software named Nano Measurer. The Mn valence states were determined by X-ray photoelectron spectroscopy (XPS). For electrical measurements, poled samples (120 ℃, 5 kV/mm, 30 min) were used. The piezoelectric coefficient (d₃₃) was measured by a model CAS ZJ-6A quasi-static meter. The electromechanical coupling coefficient (k_p) was measured by a model Agilent 4294A impedance analyzer. The temperature-dependent dielectric properties were measured by a model Agilent E4980A LCR analyzer. The high-temperature DC resistivity (ρ) was measured by a model Keithley 6517B high-resistance electrometer. The in-situ d₃₃ was measured by a model Julang TZFD-600 variable temperature quasi-static d₃₃ measurement system.

The Mn doping mechanism and high-temperature performance of BS-PT ceramics are systematically clarified. The XPS results confirm the coexistence of Mn²⁺ and Mn³⁺. To quantitatively verify the substitution site, the rietveld refinement reveals a non-monotonic evolution of unit cell volume. Based on the EDS evidence of Sc segregation without Ti precipitation, Mn ions preferentially substitute for B-site Sc³⁺. The dominant aliovalent substitution introduces defect dipoles accompanied with strong local random electric fields, significantly enhancing a relaxor behavior, while triggering a "hardening" effect that reduces tanδ and ε_r. The decoupling of piezoelectric and dielectric properties is achieved in specific compositions due to the grain boundary effect compensating for the hardening effect, especially obtaining the optimal piezoelectric voltage constant (g₃₃) at the component with x of 1.00. For high-temperature capabilities, the optimal composition (x=1.00) demonstrates a superior stability, with in-situ d₃₃ variation remaining within 20% up to 400 ℃. The thermally stable defect dipoles effectively trap oxygen vacancies, leading to a high resistivity of 10⁹ Ω·cm and an enhanced time constant of 0.072 s at 350 ℃. Consequently, the ceramic with x of 1.00 exhibits a high g₃₃ of 0.012 V·m/N when evaluated at a unified service temperature of 350 ℃, which is 50% higher than that of the undoped counterpart. These results indicate that the modified ceramic achieves an optimal balance of sensitivity and insulation for high-temperature vibration sensors.

This work clarified the Mn doping mechanism in BS-PT ceramics. The results of correlative XPS, Rietveld refinement, and EDS analysis confirmed that Mn ions could preferentially substitute for B-site Sc³⁺. The dominant aliovalent substitution induced a hardening effect, while the recovery of d₃₃ was dominated by grain size restoration. The optimal composition (x=1.00) exhibited a robust stability with d₃₃ variation within 20% at 400 ℃. The thermally stable defect dipoles could obtain a high resistivity (10⁹ Ω·cm) and time constant (0.072 s) at 350 ℃. Meanwhile, a superior piezoelectric voltage coefficient (g₃₃) of 0.012 V·m/N was achieved at 350 ℃, which was 50% higher than that of the undoped counterpart, validating its potential for high-temperature sensors.

Although composite titanium salt coagulants demonstrate excellent performance, there are still some issues and challenges that need to be addressed. Future research can focus on the following aspects: (a) Enhancing Adaptability to Real Water Bodies. Currently, the complex composition of various actual water bodies imposes higher demands on the application of composite titanium salt coagulants. To ensure stable and efficient coagulation performance under complex water quality conditions, future efforts should focus on developing novel composite titanium salt coagulants with stronger specificity and broader applicability, thereby meeting the needs of more complex and demanding application scenarios. (b) Lower- Cost Preparation of Composite Titanium Salt Coagulants. At present, the preparation of composite titanium salt coagulants largely relies on complex processes such as SAT, ED, and sol-gel methods, which hinders their large-scale application. Future research should aim to develop simpler, greener, and more economically viable preparation pathways—for instance, utilizing industrial by-products or waste materials as raw materials—while optimizing the preparation process to reduce energy consumption and production costs. (c) Ensuring Ecological and Health Safety. Current research on the toxicity assessment of titanium-based coagulants has predominantly focused on TiCl₄ and Ti(SO₄)₂. Future studies should strengthen investigations into titanium residue and its ecotoxicological effects during the use of composite titanium salt coagulants. Meanwhile, it is essential to employ a wider range of aquatic organisms (e.g., fish, shellfish, and aquatic plants) for ecotoxicity studies, and to further explore the migration, transformation, and long-term accumulation of residual titanium in water bodies and organisms. This will provide a scientific basis for comprehensively safeguarding water environments and human health.

Across diverse application domains, glass materials are engineered to meet increasingly stringent criteria with regard to performance, reliability, and sustainability. It is worth mentioning that the most advanced display modules and semiconductor chips are currently manufactured mostly in East Asia. This geographic imbalance provides unique opportunities and challenges for both of the glass industry and academia. New applications such as ultra-thin glass for flexible display modules and glass core substrate for semiconductor packaging will present unprecedented functionalities and benefits to glass materials.

The Faraday effect was discovered 180 years ago, but this phenomenon has been still utilized for practical applications as mentioned above. In particular, Tb³⁺-rich and Eu²⁺-rich oxide glasses are important for both fundamentals and applications. The Tb³⁺-rich glasses show a high transparency even in blue to ultraviolet region, so that the magneto-optical figure of merit is large enough to apply for an optical isolator. The Eu²⁺-rich glasses are ferromagnetic, so that they notably show a large Faraday effect. A new technique of glass formation such as containerless processing is effective to produce new glass compositions with further higher concentrations of rare-earth ions that are expected to exhibit a larger Verdet constant. Besides, the possible enhancement of Faraday effect based on plasmonics and Mie-tronics, i.e., the usage of localized surface plasmon resonance of metal nanoparticles and the Mie resonance of dielectric nanoparticles to increase the Verdet constant, becomes an important subject in the near future. With the development of high-power lasers, the demand for optical isolators that can operate in a wide wavelength range must increase. The oxide glasses have a promising application in such fields.

In summary, SOCs thin film preparation technologies can form a diversified system, but some common challenges remain. Although vapor-phase technologies have excellent performance, they generally face high equipment costs and great difficulty in scaling up. Liquid-phase technologies are prone to film cracks or pores due to drying and sintering stress. Future research should focus on three core directions, i.e., 1) promoting intermediate and low-temperature operation, further expanding the low-temperature application range of batteries through interface regulation and film formation process optimization; 2) pursuing high performance, developing three-dimensional structured films to expand reaction interfaces and improve mass transfer and catalytic efficiency; and 3) accelerating commercialization, optimizing low-cost preparation processes combined with intelligent manufacturing technologies, and breaking through the key technical bottlenecks of new film formation technologies. Thin film preparation technology will continue to be a core breakthrough to solve the high-temperature dependence and performance attenuation of SOCs, promoting their transition from laboratory research to commercial application.

Quartz ceramics (SiO₂) possess unique properties such as low thermal expansion, excellent chemical stability, and outstanding dielectric performance, making them widely used in semiconductor manufacturing, optoelectronic devices, and high-frequency electronic components. Traditional sintering of quartz ceramics typically requires temperatures above 1000 ℃, which inevitably induces polymorphic transformations from α-quartz to β-quartz or cristobalite, hindering the preparation of single-phaseα-quartz ceramics. Recently, the cold sintering process (CSP) has emerged as a promising low-temperature densification route for ceramics, utilizing transient liquid phases to induce "dissolution-precipitation" or interfacial reaction mechanisms. However, for low-solubility ceramics such as quartz, CSP often fails to achieve full densification and crystallization due to insufficient dissolution kinetics and weak interfacial reactivity. The critical scientific problem addressed in this work is how to effectively trigger the amorphous-to-crystalline phase transition of low-solubility quartz at low temperature, thereby enabling the preparation of denseα-quartz ceramics.

This study systematically investigates the cooperative effects of transient solvent alkalinity, sintering temperature, and uniaxial pressure on the amorphous-to-α-quartz phase transition during CSP. A transient alkaline liquid phase is introduced to regulate interfacial reactions and crystallization kinetics, aiming to provide a theoretical basis and technical strategy for the low-temperature processing of low-solubility ceramics.

Amorphous mesoporous silica (SBA-15) powders were used as the starting material. The powders were homogeneously mixed with different transient solvent phases: deionized water (neutral), 5 mol·L^-1 NH₃·H₂O (weak alkaline), and NaOH solutions of varying concentrations (0.5-10.0 mol·L^-1, strong alkaline). Approximately 0.4 g of powder was thoroughly ground with the liquid phase in a mortar and then loaded into a 10 mm diameter steel die. Uniaxial pressures ranging from 200 MPa to 600 MPa were applied, while the sintering temperature was varied between 200 ℃ and 350 ℃. Heating was conducted at a rate of 15 ℃·min^-1 and held for 40 min at the target temperature. After natural cooling, the sintered pellets were mechanically polished for further characterization.

The density of the cold-sintered ceramics was calculated by dimensional and weight measurements using a vernier caliper and electronic balance, and relative density was determined based on the theoretical density of quartz (2.2 g·cm^-3). Phase composition and structural evolution were analyzed using X-ray diffraction (XRD, Cu Kα radiation, λ = 0.154 06 nm, 50 kV, 100 mA, scanning range 10 °-90 °, step size 0.01). Fourier-transform infrared spectroscopy (FTIR-ATR) was used to identify bonding characteristics and confirm phase transitions. Microstructural evolution and fracture features were observed by field-emission scanning electron microscopy (FE-SEM). The mechanical properties of the sintered ceramics were evaluated by Vickers hardness tests (3 kgf load, 10 s dwell), flexural strength using the modified small punch (MSP) method, and fracture toughness (K_IC) calculated by the Anstis equation. Poisson's ratio and Young's modulus were determined by ultrasonic measurements.

This experimental design allows for a systematic investigation of how transient solvent alkalinity, temperature, and pressure cooperatively affect densification and amorphous-to-crystalline transformation during CSP of quartz.

The phase composition of the sintered bodies was strongly influenced by the type and concentration of transient solvent. Without a liquid phase or with neutral water, the sintered samples remained largely amorphous and exhibited low relative density (~80%). Weak alkaline NH₃·H₂O increased compaction and relative density (~92%) but failed to trigger phase transformation. In contrast, strong alkaline NaOH solutions (≥3 mol·L^-1) effectively promoted the dissolution of Si-OH surface species, forming soluble silicate intermediates. These intermediates subsequently underwent reprecipitation and recrystallization under external pressure and temperature, leading to complete transformation into α-quartz at 300 ℃ and 500 MPa. XRD and FTIR confirmed the disappearance of the amorphous broad peak and the emergence of α-quartz characteristic double peaks at 798 cm^-1 and 778 cm^-1, indicating a complete amorphous-to-α-quartz transition.

A clear alkalinity-dependent phase transition sequence was identified: amorphous → keatite (0.5 mol·L^-1 NaOH) → keatite +stishovite (1 mol·L^-1) → keatite + α-quartz (3 mol·L^-1) → α-quartz (≥5 mol·L^-1). Simultaneously, relative density increased from 71% (no solvent) to 95.7% (10 mol·L^-1 NaOH). SEM revealed that strong alkalinity produced well-defined grain boundaries and uniform microstructures, while weak or neutral conditions resulted in porous, poorly bonded networks.

The phase transition was also sensitive to sintering temperature and pressure. At 200 ℃, no crystallization occurred even at 600 MPa. Crystallization initiated at 250 ℃ and 300 MPa, and complete α-quartz formation occurred at ≥300 ℃ and ≥400 MPa. Increasing pressure facilitated particle rearrangement, pore elimination, and enhanced atomic diffusion at the interface, accelerating phase transition. A comprehensive temperature-pressure-phase diagram was established, clearly delineating the non-crystalline, partially crystalline, and fully crystalline regions.

Mechanical properties were strongly correlated with microstructure and phase composition. The α-quartz ceramics cold-sintered with 5 mol·L^-1 NaOH exhibited a Vickers hardness of 5.1 GPa, Young's modulus of 67.8 GPa, fracture toughness of 0.98 MPa·m^1/2, and flexural strength of (58 ± 7) MPa. These values represent increases of 30%, 40%, and 110% in hardness, modulus, and toughness, respectively, compared to the amorphous samples. The enhanced mechanical properties are attributed to the formation of well-bonded crystalline interfaces that enable efficient stress transfer and crack deflection, unlike the disordered amorphous structure.

This work demonstrates a controllable strategy to induce amorphous-to-α-quartz transformation in low-solubility silica ceramics through the regulation of transient solvent alkalinity during cold sintering. By introducing strong alkaline NaOH solutions (≥3 mol·L^-1), the activation energy for crystallization can be significantly reduced, enabling complete transformation at 300 ℃ under 500 MPa. The critical crystallization threshold was identified at 250 ℃ and 200 MPa, and a detailed temperature-pressure-phase diagram was established to illustrate the transition pathways. The resulting ceramics achieved a relative density above 95% and exhibited excellent mechanical performance, including a Vickers hardness of 5.1 GPa, Young's modulus of 67.8 GPa, fracture toughness of 0.98 MPa·m^1/2, and flexural strength of (58 ± 7) MPa. These results clearly indicate that alkaline regulation during CSP not only enables precise control of phase structure but also produces dense, mechanically robust α-quartz ceramics at dramatically reduced sintering temperatures. This approach provides both fundamental insights and practical guidance for the low-energy fabrication of advanced low-solubility ceramic components.

A cathode with mixed hole, oxygen vacancy, and proton conductivity extends the reactive zone for the oxygen reduction to water beyond the triple phase boundary, making the whole cathode surface an active electrocatalyst. The defect chemistry (i.e., concentrations and mobilities of point defects) of such materials with three charge carriers is complex, and some of the desired properties for a PCFC cathode material are in mutual conflict (i.e., proton uptake, electronic conductivity, catalytic activity, and long-term chemical stability). And the promising protonic cathode material needs a high catalytic activity for the oxygen reduction reaction to water to improve its performance. Nevertheless, the reactions both require the dissociation of the strong oxygen-oxygen bond.

The mechanism for this reaction is not exactly identical to that in oxide-ion-conducting cells (where the resulting oxide ions are incorporated into the cathode material, while on PCFC cathode, they are desorbed in the form of steam). The dependence of proton uptake on cation composition in cathode perovskites in order to extract the parameters that are most important for a high proton concentration. Regarding the optimization of PCFC cathode materials, refraining from striving for very high electronic conductivities is anticorrelated with proton uptake. It is prospected that the role plays due to oversized dopants in barium ferrate for enhancing the hydration properties. The beneficial effect on protonation is attributed to a higher degree of disorder in the local structure of doped samples, which translates in B-O-B bonds buckling. The B-O-B buckling reduces the Fe-O bond covalency (i.e., less Fe 3d-O 2p orbital overlap), thus decreasing the hole transfer from iron to oxygen. This leaves more negative charge density on the oxide ions, which increases their basicity and propensity for protonation.

In addition, although the existing thermogravimetric and electrical conductivity relaxation methods still have certain limitations in measuring proton concentration in mixed ionic conductors. The in-situ characterization techniques (such as in-situ transmission electron microscopy, in-situ spectroscopy, neutron diffraction, etc.) can be used to analyze the process of proton absorption and transport in mixed ionic conductors. Also, combining multi-scale simulations with experiments can further analyze numerical values such as the binding energy of proton absorption and the activation energy of diffusion. For instance, in-situ transmission electron microscopy is used to directly observe water entering Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ via introducing a small amount of water vapor into the TEM chamber. Electron energy loss spectroscopy is also used to determine the formation of oxygen bubbles on the material surface, while the protons ultimately remain within the material. This result provides the most direct evidence for studying the reactions of water and protons in mixed ionic conductors.