A porous wollastonite ceramic with high porosity and low density has been successfully fabricated at low temperature with silicate tailings and electrolytic manganese slag (MS) as primary raw materials in this study. The influences of calcination temperature, SiC, and MS addition amounts on porosity, water adsorption, pore size distribution, bulk density, and bending strength were systematically studied. The results showed that 0.4 wt

Low-temperature co-fired ceramics (LTCC) with unique multilayer interconnection architectures are indispensable for electronic communication devices and high-density integrated packaging, facing stringent demands in millimeter-wave and higher-frequency applications. This review highlights recent advances in optimizing the comprehensive performance of LTCCs and proposes strategies for further enhancement to meet the ever-growing demands of high-performance microwave devices and systems. Specifically, LTCC material designs tailored to achieve desirable properties are discussed, including appropriate permittivity, low dielectric loss, a near-zero temperature coefficient of resonant frequency, high thermal conductivity, matched coefficient of thermal expansion, and excellent mechanical strength. Additionally, innovations in sintering technologies are highlighted, such as ultra-low temperature co-fired ceramic (ULTCC) technology and cold sintering process (CSP). These approaches further reduce sintering temperatures, enabling LTCCs to integrate with a broader range of materials (e.g., silicon chips, aluminum electrodes, 2D materials, and polymers) that were previously incompatible with traditional high-temperature processes. Finally, this review offers insights into the future development directions of LTCCs in emerging applications, including 3D integration and advanced packaging, integrated communication and sensing systems, and millimeter-wave/terahertz integrated miniaturized devices for next-generation electronics.

Low-temperature co-fired ceramic (LTCC) technology is crucial for high-density integration in microwave circuits. Molybdate ceramics possess diverse compositions and typically low sintering temperatures, yet their severe reaction with silver electrodes greatly hinders LTCC applications. Inspired by the “common-ion effect”, this study proposes an Ag+ pre-occupation strategy and designs two novel AgReMo2O8 (Re = Y, Yb) ceramics. Both ceramics can be densified below 900 °C and show extremely low dielectric loss (tanδ < 2 × 10−4) at microwave frequencies. Specifically, AgYMo2O8 exhibits a quality factor (Q·f, where Q is the quality factor, and f is the operating frequency) exceeding 80,000 GHz and excellent chemical compatibility with silver electrodes, demonstrating great potential for LTCC. The polarization mechanisms and property differences were systematically elucidated through the analysis of the complex permittivity of samples across a wide frequency range. Furthermore, a high-performance X-band dielectric resonator antenna was designed based on the superior AgYMo2O8 ceramic, achieving a peak gain of 5.3 dB, and a peak radiation efficiency of 97.4%, confirming the material's promising application in advanced microwave devices. This work proposes a novel targeted development strategy for LTCC materials, which is highly conducive to the advancement of LTCC technology and the development of new functional dielectric ceramics.

Aqueous zinc-ion batteries (AZIBs) are promising for large-scale energy storage owing to their high safety, low cost, abundant Zn resources, and environmental compatibility. However, Zn metal anodes suffer from interfacial instability in aqueous electrolytes, including dendrite growth, hydrogen evolution, corrosion/passivation, and insulating by-products, which impair reversible Zn2+ plating/stripping and cycling durability. Artificial interfacial protective layers offer an effective route to stabilize Zn anodes by integrating protective and regulatory functions at the Zn/electrolyte interface. This review summarizes the failure mechanisms of Zn anodes and the design principles of artificial interphases, emphasizing homogenized Zn2+ flux and electric-field distribution, suppression of active water and side reactions, and improved ionic conductivity and interfacial stability. The compositions, fabrication methods, mechanisms, advantages, and limitations of inorganic, organic/polymeric, and organic-inorganic hybrid interphases are discussed. Finally, current challenges, including molecular-level mechanism identification, long-term structural stability, practical-condition evaluation, and scalable fabrication, are highlighted. A mechanism-oriented framework linking interfacial composition, Zn2+ transport, desolvation, water activity regulation, electric-field homogenization, and structural adaptability is proposed to guide advanced Zn-anode protection.

Enhancing the electrical performances in low-cost all-organic systems is essential to meet the requirements of rapid developments of electronic devices, especially advanced flexible electronics. However, it remains a crucial challenge to concurrently improve dielectric properties and electrical reliabilities of dielectric materials. Herein, carbon quantum dots (CQDs) are synthesized using a solid-phase strategy with an environment friendly and low-cost carbon source and introduced into polyvinylidene fluoride (PVDF) matrix to fabricate all-organic materials with enhanced comprehensive performances. Structural analyses manifest that the introduction of CQDs favors the formation of polar β-phase in PVDF and increases crystallinity, which results in enhanced polymer chain packing and decreased free volume. Well-distributed CQDs/PVDF interfaces initiate energy barriers and impede charge carrier migration at high electric fields. The nanocomposite with 5 wt% CQDs exhibits the highest electrical breakdown strength and mechanical properties, together with excellent dielectric properties and improved dielectric temperature stability. This work provides a promising approach for the development of lightweight and low-cost all-organic nanocomposite films with superior comprehensive performances for flexible dielectric applications.

The cold sintering process (CSP) is recognized as an emerging low-temperature densification strategy that provides a scalable and energy-efficient route for producing advanced ceramics and composite materials. However, its application has thus far been largely confined to small samples (diameter u0026lt; 15 mm), leaving the behavior of large-sized electronic ceramics scarcely explored. Here, a multidoped ZnO-based varistor ceramic with a diameter of 40 mm was employed to investigate the regional heterogeneity induced by cold sintering and subsequent annealing. The synergistic effects of radial pressure attenuation, liquid-phase migration, Marangoni convection, and pore evacuation accelerated densification at the edges, leading to an intensified dissolutionu2013precipitation process. Consequently, the edge region exhibited higher densification (relative density (u03C1r) = 94.3%), smaller pore volume (VP = 0.215 cm3u00B7gu22121), and larger grains (average grain size (Gaver) = 233 nm) compared with the center part (u03C1r = 91.6%, VP = 0.385 cm3u00B7gu22121, and Gaver = 189 nm). Furthermore, the regional heterogeneity originating from the CSP extended into the annealing stage, as reflected by a reduced leakage current (JL = 0.3 u03BCAu00B7cmu22122), enhanced nonlinearity (u03B1 = 66), and a high breakdown field (Eb = 1108 Vu00B7mmu22121) at the edge region. The superior electrical performance is attributed to the larger interface state density (NS = 2.9u00D71015 mu22122) and higher barrier height (u03C6b = 1.92 eV). This work elucidates the regional effect of cold sintering and offers theoretical insight for its industrial application.

Next-generation dielectric energy storage technologies, spanning renewable energy systems, electrified transportation, and advanced propulsion platforms, necessitate stable operation under extreme thermal conditions. However, the inherent trade-off between high capacitive performance and thermal stability in existing dielectric materials imposes a critical bottleneck on their practical deployment. Here we engineer an octahedrally rigid framework by 1:2 B-site ordering (Mg/Nb) within an ABO₃ perovskite structure, synergistically coupled with Sr/Bi A-site chemistry to lock structure rigidity and tailor polarizability, culminating in a high-symmetry dual-cubic phase matrix for harsh-temperature capacitive energy storage. Finite-temperature ab initio molecular dynamics simulations combined with density functional theory analysis demonstrate the retention of cubic symmetry with minimal lattice expansion up to 500  °C, consistent with the temperature-stable permittivity and bandgap required for ultra-wide-temperature capacitive energy storage. Further experiments confirm the outstanding energy storage of Sr0.7Bi0.2Mg1/3Nb2/3O3 dielectrics, achieving an energy density of 2.2 J cm-3 and an efficiency of 84% at 270 °C under 800 kV cm-1, alongside a remarkable enhancement in energy density from 3.0 J cm-3 (96.5% efficiency) to 4.9 J cm-3 at 1150 kV cm-1 enabled by the cold sintering process. The symmetry-driven design, rooted in a cubic matrix, provides critical insight into achieving capacitors with both high energy density and thermal stability under harsh operating conditions.

ZnO varistors with high breakdown strengths are essential for compact overvoltage protection devices, yet achieving high breakdown strength (E-b), high nonlinear coefficient (alpha), and low leakage current density (J(L)) simultaneously remains challenging. Herein, ZnO varistor ceramics are fabricated via cold sintering process (CSP) using hydrated metal salts as both transient liquid media and dopants. This approach enables homogeneous dopant distribution along grain boundaries through a dehydration-assisted CSP at 350 degrees C, attaining a relative density of similar to 94%. Subsequent annealing at 850 degrees C stabilizes grain boundaries and forms Bi-rich phases, constructing a high Schottky barrier of 3.36 eV. This combined approach of CSP and annealing suppresses ZnO grain growth (average grain size of 1.42 mu m) and enhances densification to 98.8%, yielding an ultrahigh E-b of 2777.52 V/mm, a high alpha of 147.53, and a low J(L) of 0.07 mu A/cm(2). This work provides an energy-efficient route to obtain superior ZnO varistor ceramics by cold sintering using hydrated metal salts, which was achieved by post-annealing.

Conventional ceramic sintering generally requires high sintering temperatures, high energy consumption, and long processing time. To overcome these limitations, a rapid and highly efficient cold sintering/spark plasma sintering (CSP/SPS) is employed, with ZnO serving as a model system to systematically investigate the effects of different transient liquid phases, including water, CH3COOH and NaOH solution on the sintering behavior. ZnO shows appreciable solubility under both acidic and alkaline conditions. During CSP/SPS, the [Zn(CH3COO)]+ complex promotes ZnO reprecipitation more effectively than [Zn(OH)4]2-, leading to superior cold sintering performance in the CH3COOH system. A relative density exceeding 95% is achieved at 100 MPa/150 degrees C in the CH3COOH system, whereas the NaOH system requires more stringent conditions (150 MPa/200 degrees C) to reach comparable densification. Due to the limited solubility of ZnO in water, high densification is achieved only under more severe conditions (150 MPa/250 degrees C). The CSP/SPS approach leverages SPS-enabled rapid heating to preserve the transient liquid phase and thereby facilitate the dissolution-precipitation process during cold sintering. Systematic comparison of different transient liquid phases reveals that densification efficiency is governed by both solubility and precipitation kinetics. Enhanced electrical conductivity in wet compacts may enable localized charge transport, while electric-field-induced point defects and liquid-solid interfacial chemical defects enhance mass transport and accelerate densification. This work provides a mechanistically informed strategy for the low-temperature, energy-efficient fabrication of ceramic materials.

In this research, an 8/20 mu s pulse current generator was used to measure the residual voltage ratio of bismuthfree ZnO varistor ceramics under different pulse currents. Furthermore, 1/200 mu s EMP pulse test is adopted to compare the peak voltage of varistors with and without bismuth. Additionally, continuous multiple impulse tests under a 75 A current were conducted to investigate the influence law of element doping content on the residual voltage ratio of varistors. The results show that when the doping amount of Ca is 2 mol%, Co is 0.5 mol%, and Cr is 0.4 mol%, the residual voltage ratio is 1.84, the stability is the best, the change rate of the residual voltage ratio is 1.1 %, the change of the nonlinear coefficient is -0.8 %, and the change rate of the breakdown voltage is -0.7 %. This study offers a new approach for the preparation of varistors with low residual voltage ratio.

The cold-sintering process (CSP) has been developed as an alternative method for the densification of ceramics at significantly low temperatures (<300°C) and in a short time (<2 h), with potential applications in the fabrication of high-performance ceramics and for the reliable integration of dissimilar materials such as metals, polymers, and ceramics into multifunctional devices. Relying upon the combined use of transient liquid media, mechanical pressure, and heat, CSP offers both fundamental and technological advantages compared with conventional sintering, minimizing energy consumption and enhancing the efficiency of the sintering process. Besides a brief overview of the densification mechanisms of CSP, knowledge obtained from earlier studies thus far regarding the effects on densification and grain growth behavior of various materials and processing parameters, such as the powder characteristics, solvent chemistry, temperature, heating rate, pressure, and dwell time, is discussed in detail in this review. Efforts that have been made to bring CSP technology into mainstream manufacturing are also described. Challenges and opportunities related to the preparation of the starting materials, the tooling quality, optimization of the process parameters, and in situ and ex situ characterization of sintered materials for the development of high-performance ceramics by the CSP method are also explored.

2D material-based reconfigurable devices present a compelling approach to advancing system integration and functionality in the post-Moore era. The all-solid-state design offers enhanced reliability and scalability of reconfigurable devices. However, realizing multifunctional reconfigurability in simple all-solid-state configurations remains a significant challenge. In this work, we address this challenge through a ferroelectric-graded-doping (FeGD) strategy to develop an all-solid-state 2D reconfigurable device featuring both structural simplicity and functional richness. The device incorporates a poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) ferroelectric layer coupled with a 2D ambipolar MoTe2 channel, enabling the integration of 12 distinct reconfigurable functionalities within a single-gate device structure. These functionalities span nonvolatile memory operations, neuromorphic computing capabilities including both homosynaptic and heterosynaptic plasticity, as well as multiple in-memory logic operations. The device demonstrates exceptional performance metrics, achieving a sub-millisecond reconfiguration speed (<1 ms), an extended retention time up to 107 s and outstanding on/off ratio exceeding 106 for nonvolatile memory operations, and large on/off ratios higher than 103 for fundamental logic operations (NAND, AND, OR, and NOR) and even more complex logic functions (IMP, RIMP, NIMP, and RNIMP), thereby establishing a versatile platform for next-generation reconfigurable electronics.

Microwave dielectric ceramics with high thermal conductivities prepared through energy saving sintering routes attract much attention to meet the requirements of multi-functionalization applications and low-energy-consumption fabrications. Herein, microwave cold sintering process (MW-CSP), as a highly efficient sintering route, is proposed to fabricate (1-x)TiO2-xBN microwave dielectric ceramics with improved thermal conductivities. All the samples are well densified with relative densities in the range of 93 and 99

The cold sintering process (CSP), which has recently attracted significant research attention, is an emerging technique that enables the densification of high-melting-point ceramics at temperatures far lower than those required for conventional sintering (CS) by utilizing solvent-assisted mechanisms. In this study, CSP is employed as a pretreatment strategy for 8 mol% yttria-stabilized zirconia (8YSZ) to modify the initial microstructural and interfacial state prior to high-temperature sintering. In parallel, Fe2O3 was introduced as a sintering aid to enhance grain-boundary diffusion during the high-temperature stage. Rather than acting as an independent densification step, CSP establishes a path-dependent initial condition that governs the subsequent densification trajectory during conventional sintering. CSP at 180 degrees C for 1 h under a uniaxial pressure of 200 MPa, followed by postannealing at 1200 degrees C for 30 min, resulted in a high relative density of 98.11% theoretical density (TD). Depending on the type of solvent, the treated samples exhibited either a high Vickers hardness (H-v = 14.99 GPa) or a high fracture toughness (K-IC = 5.56 MPa & centerdot;m(1/2)), reflecting differences in grain growth mode and crack-path geometry. Stage-resolved densification kinetics were directly monitored using laser dilatometry, enabling the identification of pressure-driven rearrangement, solvent-mediated consolidation, and thermally activated diffusion contributions. The results demonstrate that CSP pretreatment governs the particle packing topology and interfacial chemistry, while Fe2O3 addition primarily amplifies high-temperature grain-boundary diffusion. This sequential coupling establishes a mechanistic framework for path-dependent densification in CSP-assisted ceramic processing.

Microwave dielectric ceramics are critical components in wireless communications. However, it is still a challenge to develop microwave dielectric ceramics with reduced sintering temperatures, high thermal stabilities and good dielectric properties at the same time. Herein, the entropy value, which is able to modulate the grain boundary energy and adjust the inherent sintering temperature, is engineered to develop high-performance microwave dielectric ceramics with low sintering temperatures. The structure-property relationships of AWO4 ceramics, including (NaCaBi)1/3WO4, (NaCaSrBi)1/4WO4, (NaLiCaBiSm)1/5WO4 and (NaLiCaSrBiSm)1/6WO4 with increased entropy values are investigated systematically. X-ray diffraction and high-resolution TEM analyses confirm the formation of single-phase solid solutions with the tetragonal scheelite structure in AWO4 ceramics. As the number of elements in the A-site varies, the relative permittivities, Q x f values and TCF values shift in the range of 12.2-16.5, 8,000-25,000 GHz and - 32.3-31.6 ppm/degrees C, respectively. Simultaneously, the high-entropy samples demonstrate the lowest sintering temperature of 750 degrees C among the four formulations. Phillips-Van Vechten-Levine (PVL) complex chemical bond theory reveals that the covalency, lattice energy and bond energy affect the relative permittivity, Q x f value and TCF value, respectively. Raman spectra suggest that high entropy value leads to increased disorder, and infrared reflectivity spectra illustrate that the dielectric response is dominated by polarized optical phonons of [WO4] tetrahedron. It is anticipated that entropy design will facilitate the development of microwave dielectric ceramics in low temperature co-fired ceramic applications.

Field-assisted sintering technology has revolutionized material processing by integrating temperature, mechanical, electrical, and magnetic fields to achieve unprecedented densification efficiency and microstructural control. Recent advances in techniques such as hot oscillatory pressing, cold sintering, high/ultra-high pressure sintering, spark plasma sintering, ultrafast high-temperature sintering, and flash sintering have enabled the fabrication of previously unattainable materials, including ultrafine-grained ceramics, nanostructured composites, and functionally graded materials. These materials possess exceptional performances under extreme conditions, expanding applications in aerospace, electronics, energy, and biomedicine. However, the rapid development of these methods has exposed limitations in conventional sintering theory, particularly in describing mass transport and interface evolution under multi-physics coupling. This review systematically examines representative field-assisted sintering technologies and discusses their principles, equipment configurations, and application cases. By analyzing current challenges and opportunities, we aim to bridge fundamental understanding with industrial implementation, providing insights for the design and fabrication of next-generation high-performance materials.

In contemporary radio frequency (RF) systems, organic substrate materials are extensively utilized due to their low permittivity. However, their low thermal conductivity (κ ≈ 0.25 W/(m·K)) can lead to catastrophic thermal management issues in RF systems. This work proposes a LiPO3 ceramic substrate, which demonstrates ultralow permittivity (εr ≈ 4) and exceptional quality factors (tanδ at the 10-4 level). However, the temperature coefficient of resonant frequency for the LiPO3 ceramic is a large negative value (TCF ≈ -110 ppm/°C), which requires further adjustment. The εr of LiPO3 is comparable to that of organic laminates, which helps reduce signal delay, and its high quality factor gives it excellent frequency selectivity. The low ionic polarizability of Li+ and P5+ in combination with the unique (PO3)n chain structure of the phosphate groups in LiPO3 is intrinsically responsible for its low permittivity. In addition, the κ of LiPO3 exceeding 2 W/(m·K) contributes to extending the lifespan of the RF components. Furthermore, LiPO3 has a sintering temperature of only 630 °C and does not undergo chemical reactions or physical penetration with aluminum. This suggests its potential in the ultralow temperature cofired ceramics (ULTCC) field. The potential of LiPO3 was validated through an antenna array application in the 5G network. This work effectively resolves the conflict between signal delay and thermal management in high-integration RF systems.

Developing ZnO-based varistor ceramics with high breakdown field and large nonlinear coefficient remains a great challenge. To address this issue, a thermal-assisted cold sintering process was employed to densify ZnObased varistor ceramics at 300 degrees C and enhance their electrical properties through an annealing process at 900 degrees C. The pivotal roles of Dy2O3 in tailoring the microstructure and electrical properties have been systematically studied. It is found that doping of Dy2O3 suppresses ZnO grain growth, reducing the average grain size from 3.23 mu m to 2.21 mu m. Simultaneously, it introduces deep-level defects and increases interface state density, significantly elevating the Schottky barrier height from 1.74 eV to 3.15 eV. Specifically, the ZnO-based varistor ceramic with 0.5mol% Dy2O3 presents a high breakdown field of 990 V/mm, with a large nonlinear coefficient of 109, and an ultralow leakage current density of 0.07 mu A/cm2. This work provides an energy-efficient route for developing high-performance ZnO-based varistor ceramics.