Rare earth ion-doped SrTiO3-based colossal permittivity (CP, relative permittivity is defined as Ɛr) ceramics have been investigated, with two typical stoichiometric strategies commonly adopted, namely the charge compensation strategy (valence balance, Sr1−1.5xLnxTiO3) and the equimolar substitution strategy (site balance, Sr1−xLnxTiO3). However, there is currently no unified research standard, and it remains unclear which approach is superior. The Y-doped SrTiO3 (ST) ceramics were fabricated under identical conditions using two stoichiometric strategies, and a comparative study was performed. The Sr1−1.5xLnxTiO3 ceramics possess more strontium vacancies ( V^''_Sr ) and oxygen vacancies ( V_O^∙∙ ), and form more abundant defect dipoles. Consequently, the Sr0.979Y0.014TiO3 (valence balance) ceramics exhibit a CP of 24,870 and a low dielectric loss (tanδ, 0.02) at 1 kHz and room temperature. The valence balance Ln‑doped ST ceramics exhibit not only a higher Ɛᵣ across the measured frequency range but also improved frequency stability compared to the site balance ones. It is provided a theoretical basis for the design strategies toward the preparation and performance optimization of ST‑based CP ceramics.

ABSTRACT Conventional sintering (CS) suffers from prolonged processing times and high temperatures. Flash sintering (FS) in N 2 offers a promising route for the rapid, low‑temperature fabrication of high‑permittivity ceramics. However, during FS in N 2 , the low conductivity of SrTiO 3 causes surface flashover and arc breakdown, leading to insufficient densification and impairment of permittivity. In this work, metallic Cu was added to SrTiO 3 to modify conductivity, thereby steering the arc through the ceramic interior rather than along the surface. This strategy enables successful densification via FS in N 2 within 1–2 min through the Joule heating effect. During FS, electrochemical reduction caused cathode darkening (oxygen vacancy () enrichment and Ti 4+ reduction to Ti 3+ ) and anode reddening (oxidation of metallic Cu to Cu 2 O). The 2 wt %Cu‐SrTiO 3 cathode achieved high permittivity ( Ɛ r > 2431), which is attributed to interfacial polarization from heterogeneously distributed Cu particles, along with a higher concentration of defect dipoles and maximum relative density. Overall, this work overcomes arc flashover issues that previously caused insufficient densification, produces ceramics with distinct color and electrical property variations, deepens understanding of electrochemical reduction, and offers a potential route for preparing high‐permittivity SrTiO 3 via FS in N 2 .

One of the primary challenges associated with ceramic capacitors is their limited energy storage density and efficiency, which restricts their widespread application. In this study, we propose a strategy based on highentropy glass and multi-phase crystallization method to modify glass-ceramics with enhanced energy storage performance. Theoretical and experimental investigations reveal that the high entropy strategy within the glass system achieves a new balance between material nucleation and crystallization. The inherent "sluggish diffusion effect" and "cocktail effect" of high-entropy materials address the longstanding issue of grain agglomeration during the crystallization of silicate glass. The coexistence of NaNbO3, Ba2Na(Nb5O15), and Ca2Nb2O7 phases contributes to the performance optimization. Additionally, the reduction of grain size, the formation of multiphase structures, and the suppression of interface polarization collectively contributed to a higher breakdown strength (Eb), which enhanced the energy storage performance. Notably, a glass-ceramic sample with (x = 0.15) achieves a high theoretical energy storage density of 6.1 J/cm3, an ultra-high eta of 99 %, and an ultra-fast discharge rate (t0.9=24.8 ns). This work not only broadens the research scope of energy storage materials for high-field energy storage devices but also establishes a new paradigm for the development of high-performance high-entropy glass-ceramic materials.

High-temperature dielectric loss in BaTiO3-based MLCCs poses a critical reliability challenge for next-generation electronics. To address this challenge, this study proposes a simple and low-cost strategy: subjecting CuO-doped BaTiO3 ceramics to a flash joule heating (FJH) post-treatment after conventional sintering (CS). Unlike singlestep FJH sintering that couple densification with defect engineering, this approach first achieves densification ceramics via CS. Subsequently, the strongly reducing environment of FJH promotes the reduction of Cu2+ to Cu+/ Cu, which the remaining unreduced Cu2+ defects associate with oxygen vacancies to form electrically neutral defect dipoles (Cu''Ti-VO center dot center dot )& times;. This process suppresses the evolution of high-temperature defects that typically occur during conventional slow cooling and establishes effective pinning centers, thereby effectively inhibiting oxygen vacancy migration. As a result, the FJH-treated samples exhibit significantly reduced high-temperature dielectric loss (below 0.1 at 1 kHz) over a broad temperature range (-100 degrees C to 200 degrees C). Meanwhile, a slight increase in permittivity is observed, along with enhanced polarization and domain switching capability. This work provides a low-cost and industrially feasible post-treatment strategy for high-performance dielectric ceramics, demonstrating great potential for applications in high-reliability electronic devices.

In pursuit of high-performance energy storage ceramics compatible with green manufacturing, this study employs an advanced electric field-assisted sintering (flash sintering; FS) technology for 0.55BiFeO(3)-0.4SrTiO(3)-0.05NaNbO(3) (BFST-0.05NN) ceramics, addressing the inherent low breakdown strength of volatile Bi-based systems. Structural disorder induced by NaNbO3 (NN) near the morphotropic phase boundary (MPB) in the 0.6BFO-0.4STO matrix enhances relaxor behavior, while FS achieves full densification at 572 degrees C/300 s, with a sintering temperature similar to 500 degrees C lower than conventional methods (> 1000 degrees C, 2 h). This ultrafast process suppresses Bi3+ volatilization, shifting the high-field conduction mechanism from space-charge-limited conduction (SCLC) to intrinsic Ohmic behavior, and yields a uniform and dense submicron microstructure (0.42 mu m), resulting in a breakthrough breakdown strength of 340 kV/cm and a high recoverable energy density (W-rec = 4.98 J/cm(3)). Furthermore, infrared thermography validates the critical role of optimized flash durations in mitigating current localization and achieving phase-pure perovskite structures in BiFeO3-based ceramics. This work provides an effective strategy for low-temperature densification sintering of Bi-based systems, resolving the long-standing trade-off between sustainable manufacturing and excellent performance in practical applications.

Accurate prediction of dielectric breakdown remains a long-standing challenge in energy-storage dielectrics. Phase-field modeling offers valuable mechanistic insights, yet most existing simulation setups rely on needle-shaped electrodes, which fail to capture realistic device configurations and often overemphasize localized filament formation. Here, we employ phase-field modeling to systematically investigate the influence of electrode geometry (from needle-shaped to plate-shaped) on breakdown behavior in both dense and porous microstructures. Needle electrodes exhibit pronounced edge effects and are sensitive to microscopic defects such as pores, resulting in highly position-dependent, unreliable breakdown paths with significant simulated dispersion. In contrast, large-area planar electrodes, which closely mimic actual capacitor operating conditions, generate more uniform electric field distributions and yield breakdown pathways that exhibit complex network structures with excellent reproducibility. Our findings highlight the critical role of electrode configuration in determining breakdown characteristics. We strongly recommend the use of application-representative flat electrodes to obtain reliable and meaningful performance metrics for energy storage dielectrics.

As electromagnetic environmental issues become increasingly prominent, particularly in scenarios where multiple frequency bands coexist—such as 5G/satellite communications, radar, and Wi-Fi—there is a growing need for efficient, thin, and lightweight electromagnetic wave absorption materials across wide bandwidths (e.g., 2–18 GHz) to mitigate electromagnetic interference and leakage risks. Polyurethane (PU) and graphene (GR) have emerged as focal points in broadband absorber research due to their lightweight properties, processability, and tunable dielectric characteristics. This paper systematically reviews the limitations of traditional absorption materials, focusing on recent advances in PU/GR composite absorption materials regarding composition, fabrication techniques, and absorption mechanisms. It analyzes key mechanisms affecting broadband absorption—including dielectric loss, impedance matching, and multiple scattering—through specific case studies. The paper identifies key shortcomings in current research—such as impedance mismatch caused by GR agglomeration, the trade-off between thin-film thickness and broadband performance, environmental stability, and standardization of fabrication processes—while proposing feasible optimization strategies and future research directions. This aims to provide researchers in the field with clear, actionable design and fabrication recommendations.

The advancement of pulsed power technology, with its pressing demand for miniaturization and integration, necessitates the development of lead-free dielectrics that exhibit synergistically enhanced energy storage performance (ESP) and stability. In this study, a high-entropy ceramic system was established by doping Ca0.85N-d0.1Hf0.2Zr0.2Mg0.2Nb0.4O3 into a Na0.41K0.09Bi0.5TiO3 matrix, a material known for its high polarization. The substantial increase in configurational entropy (Delta Sconfig from 0.9R to 2.1R) disrupts the long-range ferroelectric order, leading to slimmer polarization-electric field (P-E) loops and enhanced efficiency. Concurrently, the introduction of diverse high-insulation oxides synergistically refines grains and widens the energy bandgap, drastically suppressing interfacial polarization. These effects collectively elevate the breakdown strength (Eb) to 400 kV/cm, representing a 4-fold increase over the unmodified matrix. The resulting ceramics exhibit a 3.87-fold increase in recoverable energy density (Wrec = 3.83 J/cm3) and a 2.08-fold improvement in efficiency (eta = 86%). Remarkably, the ceramics demonstrate outstanding dielectric temperature stability (Delta C/C25 degrees C <= +/- 15%) across an ultra-broad range of 56 to 500 degrees C. This work systematically validates high-entropy and bandgap engineering as a potent strategy for developing comprehensive performance ceramic capacitors for advanced energy storage applications.

Amidst the swift progress of electronic devices, there's an escalating need for capacitors to attain heightened energy storage capabilities (> 5 J/cm(3)) under low electric fields(< 300 kV/cm), facilitating integration and downsizing. In this research, (0.67-x)BiFeO3-0.33BaTiO(3)-xLaAlO(3) (x = 0-0.07) ceramics with ultrahigh polarization difference (Delta P = P-max-P-r) were successfully synthesized via the traditional solid-phase method. Initially, the progressive substitution of LaAlO3 was found by XRD Rietveld refinement, PFM, and dielectric spectroscopy analysis to lead to a phase transition from the R3c phase to the Pm3m phase, obtaining ultra-small and highly electric field responsive PNRs, thus facilitating the relaxation behavior and achieving low P-r values. Moreover, the introduction of La3+ enables the 0.67BiFeO(3)-0.33BaTiO(3) ceramics leading to an increased deviation of Bi ions from the centre, which maintains a relatively high P-max to achieve an ultrahigh Delta P (similar to 52.43 mu C/cm(2)), resulting in excellent energy storage density (W-rec similar to 5.71 J/cm(3)) under relatively low electric fields (270 kV/cm), along with super temperature stabilities. This study offers an effective pathway to explore the high energy storage capabilities of dielectric capacitors under low fields.

The conventional sintering (CS) of SrTiO3-based ceramics requires long time and extremely high temperature to achieve colossal permittivity (CP, r) pound, making it energy-intensive and challenging for industrial scaling. Herein, N2-Cal-FS-SYT14 CP ceramics were fabricated by a combined strategy involving thermal treatment and flash sintering (FS). This strategy reduced the onset furnace temperature while generating high power dissipation, resulting in high relative densities (>= 95.4 %) in N2-Cal-FS-SYT14 ceramics that indicate high quality and a dense microstructure. Defect structure analysis reveals that defect dipoles, such as [V & sdot;& sdot;O-V'Sr], [Ti4+& sdot;e'- V & sdot;& sdot; O - e'& sdot;Ti4+], [2Y & sdot;Sr- V'Sr], and [Y & sdot;Sr-e'& sdot;Ti4+] formed during the FS process, leading to superior dielectric properties for the N2Cal-FS-SYT14 ceramic compared to TiO2-based and CaCu3Ti4O12-based ceramics fabricated by FS, specifically a r pound of 10142 and a lower dielectric loss (tans) of 0.17, which provides a potential way to prepare SrTiO3-based CP ceramics with low energy consumption.

Increasing the interlayer spacing of metal–organic frameworks (MOFs) through multi-metal ion doping has emerged as an effective strategy to enhance electrolyte-ion transport within the MOF unit cell, enabling the design of nickel-based MOF materials with high capacity and energy density. In this work, a series of NiCo-MOF-x (x = 1–5) were synthesized by incorporating Co2+ ions into Ni-MOF. The introduction of Co2+ modulated the unit cell structure and governed the stacking configuration of MOF nanosheets. At an optimal Ni/Co molar ratio of 4:1, the NiCo-MOF-2 sample demonstrates superior electrochemical performance, delivering a specific capacitance of 1238.6 F g−1 at 0.2 A g−1. Subsequently, NiCo-MOF-2 was grown in situ on carbonized wood (CW) to fabricate a NiCo-MOF@CW composite, which exhibits an areal capacitance of 4960 mF cm−2 at 0.6 mA cm−2. An asymmetric supercapacitor (NiCo-MOF@CW//AC) was assembled using NiCo-MOF@CW as the positive electrode and activated carbon (AC) as the negative electrode. The device achieves an areal energy density of 1.88 mWh cm−2 at a power density of 2.88 mW cm−2 (1 mA cm−2), with 83.6

This study investigates the influence of thermal process on the structural, dielectric, and ferroelectric properties of sodium niobate (NaNbO3, NN) ceramics, which exhibit both antiferroelectric and ferroelectric phases, offering potential for dielectric and piezoelectric applications. The synthesis of NN is challenged by sodium volatility and difficulties in achieving stoichiometric precision at high temperatures, both of which impact its intrinsic properties. To address these challenges, calcination temperatures (750 degrees C, 800 degrees C, 850 degrees C, and 900 degrees C) and sintering temperatures (1290 degrees C, 1310 degrees C, 1330 degrees C, and 1350 degrees C) were varied to investigate their effects on phase structure, grain size, and functional properties. X-ray diffraction and Raman spectroscopy show that lower calcination temperatures promote the coexistence of antiferroelectric and ferroelectric phases, while higher temperatures stabilize the P-phase. The optimal conditions (NN ceramics calcined at 800 degrees C and sintered at 1310 degrees C) result in ceramics with fine grains, stable dielectric properties, and a broad Curie transition peak. Dielectric analysis reveals that higher sintering temperatures broaden dielectric peaks, increase phase transition temperatures (TP-R), and improve polarization and breakdown strength. Under these optimal conditions, NN ceramics calcined at 800 degrees C and sintered at 1310 degrees C demonstrate a maximum polarization of 50 mu C/cm2, breakdown strength of 199 kV/cm, and a low phase transition field of 38.96 kV/cm. This study provides insights into the temperature-dependent behavior of NN ceramics and strategies for optimizing their properties for advanced applications.

Hydrogel has developed into a very important platform in solar interface evaporator.However,the current hydrogel evaporators are usually three-dimensional evaporators,which will consume a lot of raw materials.Thus,a new two-dimensional hydrogel evaporator is urgently needed to alleviate this problem.Here,a double layer hydrogel evaporator was designed by twice vacuum filtration.Furthermore,through the arched design and the introduction of concentrated brine drainage system,the hydrogel evaporator has enhanced water transportation and tailored water transportation path.Such a unique drainage evaporation system greatly improves the stability of the evaporator.Thereby,a good balance is established between photothermal conversion and water supply,and solar energy is utilized efficiently.It can remain stable in continuous evaporation for up to 12 h with an excellent evaporation rate of 2.70 kg m -2 h -1 under 1 sun irradiation.Meanwhile,the drainage system realized the 1.8×10 -10 mol m -2 s -1 diffusion flux of concentrated brine.Through one-time freeze-drying preparation,an arch-shaped drainage evaporator was used to prepare an evaporation area of more than 20 cm 2 .With the self-made condensate collecting device in outdoor environment,the fresh water yield reaches 7.5 L m -2 d -1 .This provides a new scheme for building a new hydrogel evaporator and solving the fresh water crisis.

Electrode interface effects on electrical properties of solid-state synthesized Sr0.99La0.01TiO3 (SLT) ceramics were investigated. Ultra-high insulation samples were fabricated through oxidation treatment and coated with three electrodes: Coated silver (Ag), Sputtered Ag, and Sputtered gold (Au). Systematic comparisons revealed that ion-sputtered electrodes form continuous electrode films, creating interfacial Schottky barriers and enhancing dielectric permittivity and resistivity. Sputtered Au samples demonstrated optimal performance with Colossal Permittivity (CP, epsilon' = 30430) and low dielectric losses (tan delta = 0.03) at 1 kHz, and DC resistivity of 2.07 x 10(11) Omega center dot cm. However, sputtered electrodes significantly increased tan delta at elevated temperatures (>200 degrees C) in medium-high frequency ranges (1-100 kHz), attributed to thermally activated interfacial polarization. Screen-printed (Coated) electrodes showed inferior interface continuity but better high-frequency stability. Electrode fabrication methods critically influence dielectric responses through interface barrier formation and contact quality, with key mechanisms involving Schottky barrier modulation of charge injection and interface-limited conduction processes, providing guidance for electrode selection in high-performance dielectric applications.

At present, the excellent energy storage density of pulse capacitors often depends on ultra-high operating electric field (>500 kV/cm). Owing to the danger of high voltage and the high cost of insulation technology, it is vital that achieving superior energy storage density (Wrec > 3.5 J/cm(3)) at low electric fields (<220 kV/cm). To overcome the above concerns, the Na0.4K0.1Bi0.5TiO3 ceramic with high Pmax are selected as the matrix, the (Ca0.2Sr0.4Ba0.4) (Zr0.5Ti0.5)O-3 linear dielectrics are introduced as additives to modulate configuration entropy. Utilizing entropy engineering, the phase structure, dielectric properties and relaxor behavior of samples are optimized. When the configurational entropy reached 1.96 R, a large Wrec of 3.78 J/cm(3 )is realized at a low electric field of 180 kV/cm. In addition, the optimum sample exhibits outstanding energy storage stability at 25-175 degrees C and 1-100 Hz. These findings suggest that entropy engineering is a promising candidate for next-generation ceramic capacitors under low electric fields.

Advancing lead-free dielectric ceramics with ultrahigh energy storage density (W-rec) is essential for next-generation pulse power systems. Yet, their capabilities continue to be hindered by the conflict between polarization difference (Delta P) and breakdown strength (E-b). This study proposes a perovskite-pyrochlore composite architecture within (1-x)(0.67BFO-0.33BTO)-xSmNbO(4) (SN-x) relaxor ferroelectrics to optimize energy storage performance. SmNbO4 (SNO4) is introduced to the high polarization 0.67BFO-0.33BTO system to enhance structural disorder through the A/B site ionic radius mismatch. This disrupted long-range order, promoted a rhombohedral to a pseudo-cubic phase transition, and established nanodomains with rapid polarization response, achieving a large Delta P(similar to 44.76 mu C/cm(2)). Secondly, SNO4 incorporation induced the formation of a highly insulating Bi2Ti2O7 secondary phase, which is distributed within the matrix to form a perovskite-pyrochlore composite, elevating E-b by 2.37 times (from 150 to 355 kV/cm). Through a synergistically optimized strategy combining R/PC phase ratio regulation with perovskite-pyrochlore composite engineering, the SN-0.03 composite ceramic achieves a W-rec of 6.12 J/cm(3) (3.62-fold enhancement) by concurrently attaining a high Delta P and superior E-b with excellent frequency-temperature stability, providing a practical pathway for developing lead-free dielectric capacitors with high energy storage capabilities.

The application of Sodium niobate (NaNbO3, NN) ceramics with antiferroelectric (AFE) crystal phase faces the severe limitations in low energy density and efficiency due to the instability of the antiferroelectric phase and relatively low breakdown strength. The traditional methods still rely on a large amount of experimental verification. However, the internal mechanism remains unclear. To address this challenge, in the present study, the results of A-site defect engineering from density function theory (DFT) guides to design the modified ingredient of (1-x)NaNbO3-xBi1/3SbO3 ceramics with more stable AFE P phase. The theoretical results indicate that the BiSbO3 (BS) doping helps to induce a crystal phase transition from the stable ferroelectric (FE) to the more stable AFE state, with an energy difference of 9.762 meV. The main reason is that doping with BS suppresses the distortion index D of BO6 from 4.39 to 2.86 and increases the theta caveraged tilting angle from 25.5 to 26.4, thereby significantly stabilizing the AFE P phase. However, this also generates Na vacancies, necessitating the formation of oxygen vacancies to maintain defect balance, which adversely affects the structural stability and breakdown strength of NN. First-principles calculations indicate that inhibiting oxygen vacancy formation raises the bandgap from 1.41 to 2.45 eV, thereby enhancing structural stability and breakdown strength. Guided by these theoretical insights, doped NN ceramics were heat-treated in oxygen atmosphere, and their insulation performance was evaluated. The results confirm the effectiveness of the oxygen vacancy suppression strategy. Ultimately, the experimental findings support our theoretical predictions, providing a strong theoretical and experimental foundation for improving the energy storage performance of NN-based AFE ceramics.

The insufficient energy storage properties (ESPs) of lead-free dielectric ceramics at low electric fields (E) hinder their applications in the integrated and miniaturized electronic equipment. From this perspective, a synergetic tactic for enhancing the ESPs of (1-x) (Na05Bi0.5)(0.75)Sr025TiO3-xCa(Mg1/3Ta2/3)O-3 ceramics at low E is proposed by constructing composite ceramics in combination with the design of average ionic polarizability. Consequently, the best recorded ESPs (recoverable energy density W-rec similar to 6.7 J/cm(3) and energy efficiency eta similar to 92.5 %) contrasted to other lead-free ceramics at the same E (260 kV/cm) are attained in the x = 0.15 ceramics. This is owing to the improved breakdown E caused by the second phase Bi4Ti3O12 and the retentive high-polarization characteristic of matrix. In addition, rapid discharge time (similar to 66.8 ns), excellent thermal (30-130 degrees C) and frequency (1-100 Hz) stability are also achieved. Hence, the present work offers an innovative insight into the optimization of comprehensive ESPs for dielectric ceramics at low E.