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With the rapid development of integrated circuits, TiO 2 -based colossal dielectric constant ceramics have been widely studied as a critical alternative material in MLCC (Multilayer Ceramic Capacitors). However, the preparation technique is primarily based on the traditional solid-phase reaction method. In this work, (In 0.5 V 0.5) 0.1 Ti 0.9 O 2 , (In 0.5 Nb 0.5) 0.1 Ti 0.9 O 2 , and (In 0.5 Ta 0.5) 0.1 Ti 0.9 O 2 (abbreviated as IVTO, INTO, and ITTO) ceramics were prepared by a sol-gel method. In comparison, Nb5+ (r = 0.64 Å) and Ta5+ (r = 0.65 Å) have close ionic radii, which are more susceptible to Ti4+ (r = 0.745 Å) sites substitution than V5+ of a small ionic radius (r = 0.54 Å), effectively facilitating the carrier concentration. Meanwhile, the Ta5+ has another advantage in refining the ceramic grain size to further improve grain boundary resistance. The ITTO ceramics show a colossal dielectric constant of 9.3 × 104, low dielectric loss of 0.07 (1 kHz, room temperature), and stable temperature application range for X9F (−55 °C–200 °C，Δε r /ε 25 °C ≤ ±7.5 %). The dielectric mechanism is related to the internal barrier layer capacitance (IBLC) effect. Thus, this work as a novel strategy provides an effective mean for further development of future colossal dielectric constant materials. [ABSTRACT FROM AUTHOR]

The Pechini method was used for the first time to synthesize the phase-pure nickel-containing cubic pyrochlore Bi 2 NiNb 2 O 9 (space group Fd-3m, a = 10.5371(5) Å), while the solid-phase reaction method provided no possibility to obtain impurities-free pyrochlore. At a synthesis temperature of 950°С, low-porosity ceramics with indistinct grain boundaries were formed. The results of elemental mapping indicated a uniform distribution of metal atoms on the surface of the sample. The X-ray energy dispersive analysis showed that the chemical composition of the synthesized sample corresponded to the predetermined theoretical composition. The calcination of the sample synthesized by the Pechini method was studied by the thermal analysis up to 1100°С. The functional composition of intermediate synthesis products was analyzed by vibrational spectroscopy (FTIR). In the FTIR spectrum of pyrochlore (4000–400 cm−1), absorption bands were identified at 829, 540, 654, and 490 cm−1. The dielectric properties of the pyrochlore were studied using an impedance spectroscopy. Pyrochlore Bi 2 NiNb 2 O 9 has the high relative dielectric permittivity of 145 and low dielectric losses of 0.001 (at 24°С, 1 MHz), which make it a promising for dielectric in multilayer ceramic capacitors. [ABSTRACT FROM AUTHOR]

A supercapacitor (SC) is considered to be one of the best energy storage devices due to its high-power density, long lifespan, fast charge storage capability, and eco-friendliness. Ceramics with low-cost, nontoxic, high efficiency, and stability are the suitable and promising materials for performed supercapacitors at room temperature. As proposal, we synthesized by sol–gel method the ceramics Ba(Ti1-xMnx)O3 (where x = 0, 1, 2, or 3%) to study the effect a low rate of manganese doping on their morphological, structural, dielectric, and optical properties. The microstructure of the sintered ceramics was examined using scanning electron microscope (SEM), and the results reveal that the average grain size (AGS) of the ceramics (0.663–1.018 μm) increases with increasing Mn doping content. The optical behavior was studied by UV–visible spectroscopy, and the results indicate that Mn doping reduces the band gap (Eg) from 3.27 to 2.79 eV thus, the possibility of using these materials in photocatalyze applications. The dielectric properties of all studied samples were investigated at the temperature range 30–400 °C and frequency range 103–106 Hz. Significant modification in dielectric permittivity and an appreciable decrease in dielectric losses were observed when adding Mn2+ ions to BaTiO3 ceramics. Variations in dielectric properties and AC conductivity, as a function of frequency, reveal a relaxation mechanism related to the Maxwell–Wagner interfacial polarization. The obtained results suggest the use of prepared ceramics in capacitor and actuator applications at room temperature (RT). [ABSTRACT FROM AUTHOR]

The addition of Mg generally enhances the high-temperature stability and reliability of BaTiO 3 -based multilayer ceramic capacitors (MLCCs). Herein, a series of Mg-doped BaTiO 3 -based ceramics and ultra-thin MLCCs were successfully fabricated, and the coherent and semi-coherent interface has been observed in samples. Based on the density functional theory (DFT) calculations, the improvement in temperature stability is due to changes in the coherent interface and electronic structure that promote the formation of polar nano-regions (PNRs) and induce relaxation behavior. Based on the atomic displacement, it is found that the excess substitution released the coherent stresses in the form of defects and formed semi-coherent interfaces. The reliability degradation of MLCCs is mainly due to the evolution of the semi-coherent interfaces. This work points out an avenue to obtain high-temperature stability and high reliability in BaTiO 3 -based MLCCs. [ABSTRACT FROM AUTHOR]

Titanite CaTiSiO 5 (CTS) is considered to be a promising dielectric material for preparing high-voltage multilayer ceramic capacitors because it exhibits a positive bias dependence of the dielectric permittivity due to its antipolar crystal structure. In this study, we investigated the dielectric response and breakdown strength of CaTiGeO 5 (CTG), a structural analog of CTS, inspired by its higher low-field dielectric permittivity. Particular attention was paid to the sintering temperature to reveal the effect of the microstructure and loss of volatile Ge on the electrical properties of CTG. Dense CTG ceramics with relative densities above 97 % and grain sizes between 1.3 and 3.4 μm were obtained through a conventional solid-state reaction route at sintering temperatures between 1150 and 1250 °C. A secondary phase of CaTiO 3 was formed in the ceramics sintered at 1200 and 1250 °C due to Ge loss, but this phase was easily removed by surface polishing alone. The sintering temperature largely affected the dielectric breakdown strength through microstructural development, resulting in the highest breakdown strength of 1190 kV cm−1 for a sample sintered at 1200 °C, while it did not change the low-field dielectric properties of the samples. Furthermore, the sample retained high breakdown strength of >900 kV cm−1 at elevated temperatures up to 150 °C and exhibited a nonlinear polarization response, resulting in the positive electric field dependence of the dielectric permittivity. [ABSTRACT FROM AUTHOR]

(Pb,La)(Zr,Sn,Ti)O3‐based antiferroelectric ceramics have excellent energy storage performance(more than 90% efficiency), which make them have great application advantages in the field of ceramic capacitors. However, the sintering temperature of (Pb,La)(Zr,Sn,Ti)O3‐based antiferroelectric ceramics is generally above 1250 °C, which limits application as a material for ceramic capacitors. Cu inner electrode has a low co‐firing temperature and high conductivity and a low cost price, making it more competitive in the field of ceramic capacitor inner electrode. Therefore, the first step is to reduce the sintering temperature of (Pb,La)(Zr,Sn,Ti)O3‐based ceramics to below 1000 °C(co‐firing temperature with Cu inner electrode), which is the key and difficult point. In this paper, Pb0.94La0.02Sr0.04(Zr0.45Sn0.47Ti0.08)0.995O3(PLSZST) antiferroelectric ceramics are doped with ZnO, which effectively reduce the sintering temperature. Among them, PLSZST‐1 wt% ZnO is sintered at an ultra‐low sintering temperature (TSintering = 940 °C), which is 330 °C lower than that of PLSZST(TSintering = 1270 °C) without doping ZnO. At the same time, PLSZST‐1 wt%ZnO obtain a recoverable energy density of 4.26J cm−3 and an energy efficiency of 95.5% at 230 kV cm−1. The pulse discharge energy density (Wdis = 3.92 J cm−3) and discharge time (t0.9 = 351 ns) are obtained at 220 kV cm−1, and the current density (CD = 1338A cm−2) and power density (PD = 134MW cm−3) are obtained at 200 kV cm−1. The results provide a possible material basis for Cu internal electrode ceramic capacitors. [ABSTRACT FROM AUTHOR]

Dielectric ceramics have attracted significant attention in power electronic systems, owing to their exceptional charging and discharging speeds, as well as their high power density. However, simultaneously achieving a high recoverable energy density (Wrec) and high efficiency (η) in high‐voltage dielectric ceramics remains a challenge for applications where a high breakdown electric field (Eb) is required. In this study, high‐quality (1 – x)NaNbO3–xSr0.7Bi0.2(Mg1/3Nb2/3)O3 [(1 – x)NN–xSBMN] ceramics were prepared based on an optimization strategy combining phase structure with microstructural regulation. A quasilinear P–E loop with negligible hysteresis was realized in the ceramic with x = 0.4, excellent Wrec of 5.61 J/cm3, and high η of 85.1% obtained at a largely improved Eb of 710 kV/cm. To the best of our knowledge, the Eb of 710 kV/cm is one of the highest values achieved in dielectric ceramics to date. The noticeable reduction in grain size (∼0.95 µm) and increased bandgap improve the Eb to an ultra‐high level, which is a crucial factor in high energy storage density. The coexistence of a few antiferroelectric phases and the dominant paraelectric phase is the structural origin of the comprehensive energy‐storage performance improvement. Therefore, our research develops a unique approach to unleash the potential in NaNbO3‐based ceramics, holding great promise for application in high‐voltage dielectric capacitors. [ABSTRACT FROM AUTHOR]

La-doped BaTiO 3 ceramics are essential materials in electronic devices, finding applications in multilayer ceramic capacitors and positive temperature coefficient thermistors. While the electrical properties of La-doped BaTiO 3 have been investigated, the impact of its room-temperature resistivity anomaly on dielectric properties remains unclear. We synthesized pristine and La-doped BaTiO 3 (0.1 – 0.5 mol%) powders via hydrothermal methods, and then sintered bulk samples. Their resistivities (DC and AC), Curie temperature, room-temperature dielectric constant, and lattice volume with varying La doping concentrations were characterized. Beyond 0.3 mol%, the shift from electronic to ionic charge compensation mechanisms resulted in abrupt changes in resistivities, Curie temperature, and dielectric constant near 0.3 mol%. Given minimal changes in average grain size and relative density near 0.3 mol% La, the dominant factor influencing the dielectric constant peaking near this concentration was the shift in charge compensation mechanism. [ABSTRACT FROM AUTHOR]

Due to the demands of miniaturization, weight reduction and green development for electronic devices, development of lead-free dielectric ceramic capacitors with high recoverable energy density (W rec) and energy storage efficiency (η) attracts much attention. To this end, (1- x)[0.75(Na 0.5 Bi 0.5)TiO 3 -0.25SrTiO 3 ]- x NdNbO 4 (abbreviated as: NBST- x NN) ceramics were fabricated through a solid-state reaction method. After adding NN, the non-perovskite phase of Bi 2 Ti 2 O 7 (BTO) with low dielectric constant (ε r) and loss (tan δ) is generated. Finite element software (COMSOL) was used to explore the influence of the BTO phase on breakdown strength (E b). The simulation result indicates that the BTO phase with a low ε r concentrates a larger local electric field (LEF), and thus weakens the LEF loading in the main perovskite phase, which is beneficial for enhancing E b. Moreover, NN doping significantly decreases the oxygen vacancy concentration in NBST ceramics, which plays a key role in improving E b. On the other hand, as NN content increases, the hysteresis of the polarization (P)-electric field (E) loops is substantially suppressed, and the polarization saturation is delayed, which can be ascribed to the appearance of the BTO phase having a linear dielectric characteristic and to the enhanced fluctuations of composition and charge by NN doping. Benefitting from the above factors, the optimal energy storage performance (ESP) with a W rec of 4.14 J/cm3 and an η of 90 % is obtained in NBST-0.08NN ceramics. Meanwhile, the ESP of NBST-0.08NN ceramics shows good charge-discharge properties and thermal stability. In conclusion, these results demonstrate that NBST-0.08NN ceramics are promising candidates as environment-friendly dielectric capacitor materials. [ABSTRACT FROM AUTHOR]

As the demand for miniaturization of electronic devices increases, ceramics with an ABO3 structure require further improvement of the dielectric constant with high permittivity. In the present work, Ba1−1.5xBixTiO3 (BB100xT, x = 0.0025, 0.005, 0.0075, 0.01) ceramics were prepared via a solid-state reaction process. The effect of Bi doping on dielectric properties of lead-free relaxor ferroelectric BaTiO3-based ceramics was studied. The results showed that both colossal permittivity (37,174) and a temperature stability of TCC ≤ ±15% (−27–141 °C) were achieved in BB100xT ceramics at x = 0.5%. The A-site donor doping produces A-site vacancies, a larger space for Ti4+, and fluctuation of the component, which is partially responsible for the high permittivity and responsible for the temperature stability. Meanwhile, the contribution of defect dipoles, and IBLC and SBLC effects to polarization leads to the colossal permittivity. The formation of a liquid phase during sintering promotes mass transfer when the doping content is higher than 0.5%. This work benefits the exploration of novel multilayer ceramic capacitors with colossal permittivity and temperature stability via defect engineering. [ABSTRACT FROM AUTHOR]

The pursuit of lead-free ceramic capacitors with superior energy storage properties has garnered increasing attention. Herein, 0.7Bi 0.5 Na 0.5 TiO 3 -0.3SrTiO 3 - x La (BNT-ST- x La) ceramics were synthesized via citrate combustion technology. The results show that La doped BNT-ST induces dielectric relaxation behavior and promotes the formation of nanoscale domains, which has been confirmed by PFM and TEM, and slim hysteresis loops are realized as addition of La. The recoverable energy-storage density (W re of 2.05 J/cm3) and efficiency (η of 82 %) are obtained in 4 mol% La doped ceramic under relatively low electric field of 170 kV/cm. The energy-storage performances of the ceramics show excellent frequency stability (W re varies <1.9 % and η varies <3.1 % at 5 Hz–100 Hz) and thermal stability (W re varies <1 % and η varies <6.1 % within 23 °C to 73 °C). It is revealed that the introduction of La results in the formation of nanodomains with currently improved energy storage properties. [ABSTRACT FROM AUTHOR]

Herein, NaTaO 3 (NT) is introduced into 0.7Bi 0.5 Na 0.5 TiO 3 -0.3 Sr 0.7 La 0.2 TiO 3 (BNSLT) ceramic to increase the content of the highly stable P4bm phase, constructing a temperature-insensitive phase structure and permittivity over a wide temperature range (25–300 °C); thus, excellent thermal stability (W rec = 4.68 ± 0.50 J/cm3, η = 89.0 ± 2.1%) over an ultra-wide temperature range (20–240 °C) is realized, superior to most lead-free ceramics. The co-substitution of heterovalent ions at both A and B sites in BNSLT leads to enhanced relaxor state and bandgap, delayed saturation polarization, reduced grain size and permittivity. Thereby, an excellent recoverable energy storage density (W rec = 8.55 J/cm3), high efficiency (η = 89.5%), and extremely high power density (P D = 320 MW/cm3 at 280 kV/cm) are obtained in BNSLT-8%NT ceramics. This work offers a new paradigm for the development of ceramic capacitors with both excellent comprehensive energy storage performance and high-temperature working stability. [ABSTRACT FROM AUTHOR]

The inferior energy storage capability and high temperature reliability of ceramic capacitors are a main factor restrict the further application. In this article, we propose to overcome the above issues through increasing the configuration entropy (∆ S config). The novel high entropy ceramics (1- x) (Na 0.5 Bi 0.47 La 0.03) 0.94 Ba 0.06 TiO 3 - x Ca 0.7 La 0.2 Ti 0.85 Hf 0.15 O 3 were successfully designed and synthesized to enhance comprehensive performance. With the ∆ S config rises from 0.98 R to 1.54 R, the optimum composition exhibits outstanding recoverable energy storage density (W rec) of 6.21 J/cm3 under 420 kV/cm and dielectric high temperature stability (∆ C / C 25 °C ≤ ± 15%, −59–372 °C) in accordance with X9R, which can be ascribed to refined grain size, improved bandgap width, inhibited leakage current and interfacial polarization and modified relaxor behavior caused by the improvement of ∆ S config. Interestingly, the high entropy composition was firstly tested fatigue endurance at 150 °C and 200 °C and shown prominent high temperature reliability. These results provide a new viewpoint for designing high temperature capacitors. [ABSTRACT FROM AUTHOR]

The study investigated the formation of inhomophase ceramics through Zn doping in Bi 2 СrTa 2 O 9.5–Δ. It was found that all Bi 2 Zn x Cr 1– x Ta 2 O 9.5–Δ (0.3 ≤ x ≤ 0.7) investigated samples crystallized in the pyrochlore structural type (sp. Gr. Fd-3m) and contained an admixture of triclinic β-BiTaO 4 (up to 24 wt %, sp. gr. P-1), with the admixture concentration proportional to the degree of zinc doping. It was shown that impurities in the samples could be eliminated by creating a defective bismuth sublattice proportional to the impurity content, resulting in single-phase Bi 2– y Zn x Cr 1– x Ta 2 O 9.5–Δ (y ≤ 0.5, 0.3 ≤ x ≤ 0.7) samples with the pyrochlore structure. The unit cell parameter of pyrochlore increased with an increase in zinc ion content in the samples from 10.4493 Å (x = 0.3) to 10.4976 Å (x = 0.7). The microstructure of ceramics was represented by individual slightly melted grains 0.5–2 μm in size, which increased in size and fuse with each other with an increase in zinc content. The near edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) data showed that zinc doping did not change the oxidation degree of bismuth and tantalum in pyrochlore, with the ions in charge states Bi(+3), Zn(+2) and Ta(+5). The study also observed an energy shift of the absorption band in the Ta 4f spectrum toward lower energies (Δ E = 0.55 eV) characteristic of tantalum ions with an effective charge (+5–δ) and a shift of the Bi 4f 7/2 and Bi 4f 5/2 bands shift to lower energies with increase in x (Zn), due to the distribution of some Zn(II) ions in the bismuth position. The oxidation degree of chromium ions in the samples was mainly (+3), with some chromium ions oxidized and having an oxidation degree close to (+6) according to NEXAFS data. The studied ceramics showed promise as dielectrics for multilayer ceramic capacitors and devices for microwave applications due to their low sintering temperature and high porosity. [ABSTRACT FROM AUTHOR]

Lead-free Sr0.6Ca0.4TiO3 ceramic was prepared by solid-state reaction route. X-ray diffraction technique showed the phase purity and identified the orthorhombic perovskite structure. Scanning Electronic Microscopy observation evidenced homogeneous morphology and dense microstructure. Electrical conduction and dielectric relaxation mechanisms at high temperature have been studied by complex impedance measurement techniques over a wide range of frequencies and temperatures, from 100 Hz to 1 MHz and from 573 K to 783 K. Fitting of impedance measurements allowed us to study grains and grain boundaries electrical characteristics and their contribution to the conduction and dielectric relaxation processes in the ceramic. Electrical conduction in grains is due to oxygen vacancy jumps for temperatures below 733 K and to polarons above 763 K. Electrical DC conductivity in grains and grain boundaries is mainly due to oxygen vacancies. Impedance measurements and relaxation time distribution function calculations show non-Debye-type relaxation effects for both grains and grain boundaries. [ABSTRACT FROM AUTHOR]

In pursuing enhanced performance for electronic applications, we synthesized ferroelectric materials, specifically Ba(1-x)Nd2x/3TiO3 (BNdTx) nanoceramics, utilizing solid-state reaction techniques coupled with microwave heating treatment. Our investigation involved varying Nd3+-doping levels (x = 0%, 2%, 4%, and 8%) to tailor the material's properties. XRD analysis confirmed the presence of a single-phase tetragonal perovskite structure (space group P4mm). A comprehensive examination of the partial density of states for both undoped and Nd3+-doped BaTiO3 was undertaken to discern the impact of Nd3+-doping on the energy bands. Microscopic analysis revealed the presence of pores in the samples, accompanied by a reduction in grain size with increasing Nd3+ content. The introduction of Nd3+ induced a shift in the Curie temperature (TC) towards room temperature. Simultaneously, the dielectric characteristics exhibited a consistent value above 1900, with a low loss of less than 5% observed across a range of temperatures (30–100 °C). Notably, the sample with x = 4% demonstrated thermally stable dielectric properties, suggesting its potential suitability as a material for Multilayer Ceramic Capacitor (MLCC) applications. Integrating microwave sintering and ball milling techniques is a significant development in advanced materials engineering, specifically in producing Multi-Layer Ceramic Capacitors (MLCC). The practical implementation of these novel methodologies is essential in decreasing particle size, which is a critical determinant in improving thermal stability. Ball milling further refines the particle size distribution, whereas microwave sintering guarantees a more uniform and fine-grained microstructure through its rapid and effective heating capabilities. The capacitors acquire enhanced thermal stability and a more refined material granularity through this synergistic combination. By achieving a more uniform and compact ceramic structure, these processes result in a finer particle size, enhancing the overall performance and dependability of MLCC capacitors. The increasing need for miniaturized and high-performance electronic components has focused on utilizing microwave sintering and ball milling. These processes are at the forefront of technological advancements in the pursuit of improved thermal properties and increased efficiency in manufacturing MLCC capacitors. [ABSTRACT FROM AUTHOR]

(1 −x)(K 0.8 Na 0.2)NbO 3 –xBaTiO 3 [(1 −x)(K 0.8 N 0.2)N–xBT] ceramics are well densified at 1080 °C for 2 h. The Curie temperature (T C) and orthorhombic–tetragonal phase transition temperature (T O-T) of the ceramics considerably decrease and broaden with increasing x. Moreover, the ceramics (x ≥ 0.08) have large relaxor properties. The (1 −x)(K 0.8 N 0.2)N–xBT ceramics (0.09 ≤x ≤ 0.11) exhibit excellent thermal stability of dielectric properties, satisfying the X9R multilayer ceramic capacitor (MLCC) specification requirements. However, the (1 −x)(K 1−y N y)N–xBT ceramics (0.0 ≤x ≤ 0.3 and y = 0.5 and 0.8), which contain a large amount of Na+ ions, cannot satisfy the X9R MLCC specification requirements owing to the weakened relaxor properties and reduced decreasing rate of T C and T O-T. An MLCC is fabricated using the 0.9(K 0.8 N 0.2)N–0.1BT ceramic. The MLCC complies with the X9R MLCC regulation requirements and has excellent stability of the applied electric field. Therefore, the 0.9(K 0.8 N 0.2)N–0.1BT ceramic serves as a promising candidate for X9R MLCC devices. • (1−x)(K 0.8 N 0.2)N–xBT ceramics (0.09 ≤ x ≤ 0.11) exhibit large relaxor properties. • The ceramics (0.09 ≤ x ≤ 0.11) satisfy X9R MLCC specification requirements. • An MLCC was fabricated using the 0.9(K 0.8 N 0.2)N–0.1BT ceramic. • 0.9(K 0.8 N 0.2)N–0.1BT MLCC satisfied the X9R MLCC regulation requirements. • This MLCC has excellent stability of the applied electric field. [ABSTRACT FROM AUTHOR]

Tape casting is currently the mainstream method for preparing multilayer ceramic capacitor (MLCC). However, digital light processing (DLP) shows great promise for MLCC preparation due to its planar exposure and layer-by-layer printing characteristics. In this study, La x Ba (1-x) (Zr 0 · 1 Ti 0.9)O 3 (LBZT) ceramics were fabricated using DLP molding. The effects of La content change on the phase composition, microstructure, and properties of the materials were investigated. A stable ceramic slurry was formulated, and its rheological behaviors and cure properties were studied. TG-DTG was used to develop a two-step debinding process, and its debinding mechanism was analyzd. Finally, the samples were sintered by holding at 1300 °C for 4 h. The results showed that with the increase in La content, the phase composition gradually transformed from the rhombohedral to the tetragonal phase. The microstructure was initially gradually dense, and then the pores increased rapidly, resulting in a quick decrease in relative density. LBZT ceramics exhibited the densest structure at x = 0.006: ρ = 5.79 g/cm3 with a relative density of 95.74%, and have the most excellent dielectric properties (25 °C, 1 kHz): ε r = 7068, tanδ = 0.232. [ABSTRACT FROM AUTHOR]

Ceramic capacitors are widely used devices due to their excellent characteristics, such as rapid charge and discharge rates and high power density. However, simultaneously attaining exceptional energy storage performance and outstanding cycling stability in ceramic-based energy storage capacitors remains a considerable challenge. In this work, a multi-scale synergistic optimization strategy was proposed to enhance the energy storage performance and cycling stability of K 0.5 Na 0.5 NbO 3 ceramics, accomplished through grain refinement, introducing polar nanoregions (PNRs), and inducing weakly polar pseudo-cubic phases. As a result, ultrafine grains (∼110 nm), excellent energy storage performance [energy storage density (W rec) ∼ 3.16 J/cm3, energy storage efficiency (η) ∼ 65%], and incredible cycling stability (W rec variation: ∼0.09%, η variation: ∼0.28%) are concurrently realized in the 0.93K 0.5 Na 0.5 NbO 3 -0.07(Sr 0.7 La 0.2)(Mg 1/3 Nb 2/3)O 3 relaxation ferroelectric ceramic. This work investigates the microscopic origins of the improved energy storage performance of KNN-based ceramics and presents a synergistic optimization strategy to achieve exceptional energy storage performance and incredible cycling stability. [ABSTRACT FROM AUTHOR]

To meet the demand for miniaturization and integration of electronic and electrical equipments, developing dielectric capacitors with excellent energy storage properties is of utmost importance. Bi 0.5 Na 0.5 TiO 3 -based ceramics have been investigated extensively for potential energy storage applications. However, its low breakdown strength E b and high remnant polarization P r limit the energy storage density and efficiency (η). Therefore, we explored a synergistic design strategy of domain control and grain size adjustment via La doping to successfully synthesize 0.8Bi 0.5 Na 0.5 TiO 3 -0.2NaNbO 3 - x La 2 O 3 (0.8BNT-0.2NN- x La 2 O 3) ceramics with superior energy storage properties to overcome above issues. It shows that the composition regulation by antiferroelectric NaNbO 3 results in improved disrupted long rang order ferroelectric domain structure, effectively promoting the formation of polar nanoregions, subsequently weakening P r and enhancing relaxation behavior. The introduction of antiferroelectric NaNbO 3 effectively improves the η of the system. Moreover, the grain size is decreased and densification is enhanced after La tailoring, which is beneficial for the E b and recyclable energy storage density (W rec). Finally, a high W rec of 4.40 ± 0.20 J/cm3 and η of 80.1 ± 2.1% at 450 kV/cm are obtained in 0.8BNT-0.2NN-0.07La 2 O 3 ceramic. Besides, the sample demonstrates admirable temperature stability (25–175 °C) and frequency stability (10–100 Hz). Simultaneously, it displays stable discharge energy density, rapid discharge time of 0.36 μs, and good fatigue endurance (105 cycles). The results offer useful guidance for the design of novel ceramic capacitors with comprehensive energy storage performance. [ABSTRACT FROM AUTHOR]

As consumer electronics and industrial control systems continue to evolve, the operating temperature range of capacitors is gradually increasing. Barium titanate-based ceramic capacitors are widely used in the field of high dielectrics, so temperature-stable barium titanate-based dielectric materials have been a hot research topic in the field of dielectric ceramics. The construction of a core–shell structure by unequal doping is an effective way to obtain temperature-stable dielectric materials. At the same time, this structure retains part of the highly dielectric tetragonal phase, and materials with overall high dielectric constants can be obtained. In this work, we prepared BaTiO3-xNaNbO3-0.002Gd2O3 (x = 1.0–6.0 mol%) as well as BaTiO3-0.05NaNbO3-yGd2O3 (y = 0–0.30 mol%) dielectric ceramics. On the basis of high-electronic-bandgap NaNbO3-modified BaTiO3 dielectric ceramics, a core–shell structure with a larger proportion of core phase was obtained by further doping the amphiphilic rare-earth oxide Gd2O3. By designing this core–shell structure, the temperature stability range of capacitors can be expanded. At a doping level of 5.0 mol% NaNbO3 and 0.20 mol% Gd2O3, the room temperature dielectric constant εr = 4266 and dielectric loss tan δ = 0.95% conforms to the X8R standard (from −55 °C to 150 °C, TCC < ±15%); volume resistivity ρv = 10,200 GΩ·cm and breakdown strength Eb = 13.5 kV/mm is attained in BaTiO3-based ceramics. The system has excellent dielectric and insulating properties; it provides a new solution for temperature-stable dielectric ceramics. [ABSTRACT FROM AUTHOR]

Glass ceramic capacitors with ultra-fast discharge speed and high energy density play a key role in pulse power systems. However, the low dielectric performance of glass ceramics limits their energy storage density. To reinforce the dielectric properties and energy storage capacity of glass ceramics, the microstructures and contents of the ceramic phases composing BaO–Na 2 O–Nb 2 O 5 –SiO 2 –TiO 2 –ZrO 2 glass ceramics can be effectively controlled by adjusting different crystallization conditions. At the optimum crystallization temperature of 950 °C, the maximal theoretical energy storage density of BaO–Na 2 O–Nb 2 O 5 –SiO 2 –TiO 2 –ZrO 2 dielectric glass ceramics reaches 9.54 J/cm3 at 1394 kV/cm, which is 1.47 times that of dielectric glass ceramics crystallized at 750 °C. Moreover, glass ceramics exhibit a rapid discharge rate of approximately 0.237 μs and superior power density (2.39 MW/cm3) at 800 kV/cm. Significant enhancement in energy storage performance of the above ceramics is attributed to the component regulation and the reduction of interface polarization. [ABSTRACT FROM AUTHOR]

High-performance lead-free dielectric ceramics are key to energy storage ceramic capacitors. In this work, an effective strategy was adopted to improve the dielectric energy storage properties (ESP) of Bi 0.5 Na 0.5 TiO 3 based ceramics using CeO 2 doping. The introduction of Ce4+ refines the grain size and improves the dielectric temperature stability of the (1- x)Bi 0.4 Na 0.4 Ca 0.2 TiO 3 - x CeO 2 ceramics. However, Ce4+ is susceptible to reductive valence changes at high temperatures, forming defects that deteriorate the breakdown electric field strength (E b). To address this issue, Ce4+ valence transitions were successfully inhibited by sintering ceramics in an oxygen atmosphere. Remarkably, the E b value increases from 160 kV cm−1 for x = 0 wt% to 220 kV cm−1 for x = 0.8 wt%, and the total energy storage density increases from 1.38 J cm−3 to 2.99 J cm−3, as well as realizing a high energy storage efficiency (η ∼ 81 %). This study offers a framework for optimizing the performance of BNT-based energy storage ceramics and elucidating the precise link between valence variations and ESP. [ABSTRACT FROM AUTHOR]

As a dielectric material, BaTiO 3 -based ceramics are desirable for high performance ultra-thin multilayer ceramic capacitors (MLCCs) application. In this work, BaTiO 3 -based dielectric ceramics with superior dielectric properties were synthesized using a reducing atmosphere sintering process. It is found that the contribution of "wet" grain-boundary diffusion become significant as the oxygen partial pressure increases, resulting to a larger grain size and higher permittivity. Especially, for the specimen sintered in higher oxygen partial pressure, the stable temperature coefficient of capacitance (TCC) is dominated by irreversal domain due to the increase of super-lattice phase. Samples with higher oxygen partial pressure exhibit a higher permittivity of 2700 and better permittivity-temperature stability. Furthermore, ultra-thin MLCCs with thickness of 1 μm and capacitance of 10 μF and the TCC of X7R were successfully fabricated. This work provides a comprehensive explanation demonstrating upon the significant roles of grain size and defect engineering in the dielectric performance in BaTiO 3 -based ceramics, and points out an avenue to obtain excellent permittivity-temperature stability in ultra-thin MLCCs. [ABSTRACT FROM AUTHOR]

The high-capacity and quality ceramic materials have the potential of miniaturization and convenience for electronic components. In this work, CaMnO 3 (CMO) and La 0.5 Sr 0.5 CrO 3 (LSCO) powders are prepared by the traditional solid phase method and the laminated LSCO/CMO/LSCO samples are made via the rolling process. It can be found that the CMO and LSCO layers are clearly kept flat in co-sintered samples by SEM analysis. The capacity value of >0.1 μF/cm2(<100 Hz), the obviously reduced dielectric loss and the increased insulation resistivity are achieved in LSCO/CMO/LSCO samples at room temperature. Through the characterization of complex impedance spectroscopy, XRD and XPS, the ameliorative dielectric performance mainly depends on the interface between CMO and LSCO layers, which produces the high resistance value and blocks the long-range transition of the carriers. This phenomenon has an important significance for the development and application of large-capacity and co-sintered ceramic capacitors. [ABSTRACT FROM AUTHOR]

In this article, the dielectric properties of a Li4Ti5O12 (LTO) ceramic at the radio frequency (RF) and microwave (MW) regions were evaluated. X-ray diffraction showed that LTO was obtained without the presence of spurious and/or secondary phases. Complex impedance spectroscopy (CIS) analysis was conducted, whereas an activation energy (Ea) of 0.88 eV was observed. The temperature capacitance coefficient (TCC) was also calculated and demonstrated that LTO could be employed as a Class 1 ceramic capacitor. In the MW region, LTO presented ε'r = 25.4, tan δ = 5.7 × 10–4, and τf = -14.5 ppmºC−1, values that are interesting for devices that operate in the MW region. Numerical simulation demonstrated values of a realized gain of 4.78 dBi, a bandwidth of 227 MHz, and a radiation efficiency of 98%. Moreover, LTO was evaluated as a temperature sensor operating in the MW region and demonstrated a sensitivity of -0.06 MHz ºC−1. The values presented demonstrate that LTO could be employed in devices that operate in RF and MW regions. [ABSTRACT FROM AUTHOR]

Eco-friendly ceramic capacitors gradually become an important section of pulsed power devices. However, the synchronous realization of ultra-high energy storage density (Wrec > 6 J/cm³) and efficiency (η > 90%) is difficult. Thus, a novel multiscale amelioration strategy in Na0.5Bi0.5TiO3-based ceramics is proposed to achieve ultra-high energy storage density and efficiency. The multiscale amelioration strategy for (Na0.5Bi0.47La0.03)0.94Ba0.06TiO3 (NBLBT) ceramic focuses on grain size, bandgap width, and dielectric relaxor behavior, which can be regulated by introducing Sr(Al0.5Nb0.25Ta0.25)O3 (SANT). On the one hand, the refined grain size and increased bandgap width are conducive to improving the breakdown strength. On the other hand, the optimized dielectric relaxation behavior is beneficial to suppress the remanent polarization. Accordingly, an ultrahigh Wrec = 6.89 J/cm³ and η = 90.1% are simultaneously achieved in 0.84NBLBT- 0.16SANT ceramic. In addition, the sample synchronously possesses excellent thermal and frequency stability (a variation within 5% in Wrec and η), transient discharge rate of t0.9 ~ 78.8 ns and a high-power density of PD ~ 114.5 MW/cm³. This study provides an effective strategy to further develop pulsed power devices. [ABSTRACT FROM AUTHOR]

Multilayer ceramic capacitors (MLCCs) prepared using Ba1−xSrxTiO3 (BST) ceramics exhibit high dielectric constants (~1000), low dielectric loss (<0.01), and high breakdown voltage, with particularly significant tunability in dielectric properties (>50%) and with poor temperature stability. Doping-dominated temperature stability improvements often result in unintended loss of dielectric properties. A non-doping method has been proposed to enhance the temperature stability of BST capacitors. The composite gradient multilayer (CGML) ceramic capacitors with BaxSr1−xTiO3, where 0.5 < x < 0.8, as the dielectric, were prepared using a tape-casting method and sintered at 1250 °C. There exists a dense microstructure and continuous interface between the BaxSr1−xTiO3 thick film and the Pt electrodes. CGML ceramic capacitors feature a high dielectric constant at 1270, a low dielectric loss of less than 0.007, and excellent frequency and temperature stability. The capacitor showcases remarkable dielectric properties with a substantial tunability of 68% at 100 kV/cm, along with a notably consistent tunability ranging from 20% to 28% at 15 kV/cm across temperatures spanning from 30 to 100 °C, outperforming single-component BST-MLCCs in dielectric performance. [ABSTRACT FROM AUTHOR]

BaTiO3‐based compounds are recognized as the most common dielectric material used in multilayer ceramic capacitors (MLCCs), among which, BaTiO3‐BiMeO3 is extensively investigated to improve the thermal stability and extend the service life of MLCCs, which are strongly dependent on the conductivity at high temperatures. Despite numerous efforts have been made, the mechanism of oxygen vacancy conduction, which makes the major contributions to the conduction mechanism of BaTiO3‐based compounds at high temperatures below 450°C, is still unclear. In this paper, BaTiO3, 0.88BaTiO3‐0.12Bi(Zn2/3Nb1/3)O3, 0.88BaTiO3‐0.12Bi(Mg2/3Nb1/3)O3, and 0.88BaTiO3‐0.12Bi(Mg2/3Ta1/3)O3 ceramics have been prepared by solid‐state reaction method, and their electrical and dielectric properties have been studied in detail. Meanwhile, first principles were applied to study the mechanisms of the increase of electrical resistivity and the decrease of dielectric loss. It is found that B‐site dopants (Zn, Mg, Nb, and Ta) are effective in reducing the conductivity by inhibiting the migration of oxygen vacancies, which is a kinetics process with an increase of energy barrier. Notably, the greater ability of Zn to inhibit oxygen vacancies migration is a combination of thermodynamics (a strong ability to trap oxygen vacancies) and kinetics (an effect of block the migrating defects in the lattice). This work reveals a new insight into the mechanism of oxygen vacancies migration in BaTiO3‐based perovskite compounds, which makes BaTiO3‐BiMeO3 prospective in designing efficient and durable medium‐temperature solid oxide capacitor devices. [ABSTRACT FROM AUTHOR]

Developing dielectric ceramics with both negative temperature coefficient of capacitance (NTCC) and excellent energy storage performance is beneficial to obtain multifunctional dielectric ceramic capacitors. An effective strategy of composite modulation in the superparaelectric (SPE) state is proposed in BaTiO 3 -BaZrO 3 -CaTiO 3 (BT-BZ-CT) system to achieve the above two points. The simultaneous addition of BZ and CT to BT ferroelectrics can move the SPE state to the normal use temperature zone and the NTCC characteristic with enhanced energy storage performance can be obtained; and the intentional precipitation of CT at grain boundaries can refine the grain size, increase the bandgap, and strengthen the local electric field distribution as well, thus enhancing the breakdown electric field (E b). Benefiting from these features, EIA class I-R3L code NTCC together with a high W rec (∼3.46 J/cm3) and η (90.8%) were achieved in 20BT-40BZ-40CT system, providing a paradigm for building NTCC dielectric materials with high energy-storage performance. [ABSTRACT FROM AUTHOR]

Polycrystalline samples of (1-x)K 0.5 Bi 0.5 TiO 3 - xBaTiO 3 [(1-x)KBT - xBT] were synthesized using a solid-state reaction pathway. X-ray diffraction analysis confirmed the presence of a single-phase perovskite structure. To explore relaxation and conduction mechanisms, complex impedance spectroscopy was employed. Reduction in Curie temperature was observed as BT content increased. The grain and grain boundary contributions to relaxation was examined through complex impedance and modulus plots and quantified via fitting experimental data to an equivalent circuit model. Examination of the Complex impedance spectra uncovered the existence of dielectric relaxation characteristic of a non-Debye nature. Furthermore, the activation energy determined suggests commonalities in governing the conduction and relaxation processes in relation to temperature-dependent conductivity and relaxation time. A negative temperature coefficient of resistance behaviour was obtained from the temperature-dependent conductive study. Dielectric spectra revealed that these ceramic capacitors are useful in reduction of signal interference, signal attenuation and impedance matching circuits applications. [ABSTRACT FROM AUTHOR]

Low-voltage driven ceramic capacitor applications call for relaxor ferroelectric ceramics with superior dielectric energy storage capabilities. Here, the (Bi0.5Na0.5)0.65(Ba0.3Sr0.7)0.35(Ti0.98Ce0.02)O3 + x wt% Ba0.4Sr0.6TiO3 (BNBSTC + xBST, x = 0, 2, 4, 6, 8, 10) ceramics were prepared to systematically investigate the effect of BST content on the phase structure, microscopic morphology and dielectric energy storage properties. A single perovskite structure with a dense and homogenous microstructure is presented in all BNBSTC + xBST ceramics. A recoverable energy storage density Wrec = 1.39 J/cm3 with efficiency η = 81.5% is achieved only under a low electric field of 94 kV/cm in the optimal composition of x = 6, accompanied by an enhanced dielectric temperature stability meeting the requirement of wider working window. In addition to good frequency, anti-fatigue and temperature stability, the BNBSTC + 6BST ceramics exhibit tremendous potential for designing low-voltage driven energy storage ceramic capacitors. [ABSTRACT FROM AUTHOR]

Pulsed power and power electronics systems used in electric vehicles (EVs) demand high-speed charging and discharging capabilities, as well as a long lifespan for energy storage. To meet these requirements, ferroelectric dielectric capacitors are essential. We prepared lead-free ferroelectric ceramics with varying compositions of (1 − x)Ba0.7Sr0.3TiO3–(x)BiMg0.5Ti0.5O3 (BST–BMT) (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1) using a solid-state-reaction method. To analyze the crystallinity and structural parameters, we examined the X-ray diffraction (XRD) patterns using the pseudo-Voigt function in the FullProf software. Additionally, Raman spectrum analysis confirmed the presence of ceramic structural distortion caused by microstrain and doping. Microstructure images of the ceramic samples showed an increase in grain size from 1 to 2.4 μm and an improved distribution of grain sizes with increasing doping levels. We investigated the dielectric properties of the BST–BMT ceramic capacitors across a wide range of frequencies and temperatures. Interestingly, as the BMT content increased, the previously saturated ferroelectric (FE) curve for x = 0.01 gradually shifted towards a narrower relaxor ferroelectric (RFE) curve for x = 0.1. The most favorable effective energy storage density was observed with a BMT doping concentration of x = 0.04, which coincided with exceptionally high-energy efficiency (η ~ 91%) under a field strength of 50 kV/cm and a relatively high dielectric normalized energy storage density of 3.71 µJV−1 cm−2 due to structural modifications that causes relaxor ferroelectric behavior. More interestingly, the energy storage performance of 0.96BST–0.04BMT displays a fatigue free characteristic enduring through numerous switching cycles. We also calculated the optical bandgap (Eg) values from UV–Vis spectra and compared them with the increase in BMT concentration. The Eg value for all ceramics was approximately 3.2 eV, similar to the pure BST ceramic sample. Additionally, the resistive switching behavior demonstrated by our bulk ceramic capacitors is not commonly observed in other bulk ceramics. [ABSTRACT FROM AUTHOR]

Low-voltage driven ceramic capacitor applications call for relaxor ferroelectric ceramics with superior dielectric energy storage capabilities. Here, the (Bi0.5Na0.5)0.65(Ba0.3Sr0.7)0.35(Ti0.98Ce0.02)O3 + x wt% Ba0.4Sr0.6TiO3 (BNBSTC + xBST, x = 0, 2, 4, 6, 8, 10) ceramics were prepared to systematically investigate the effect of BST content on the phase structure, microscopic morphology and dielectric energy storage properties. A single perovskite structure with a dense and homogenous microstructure is presented in all BNBSTC + xBST ceramics. A recoverable energy storage density Wrec = 1.39 J/cm3 with efficiency η = 81.5% is achieved only under a low electric field of 94 kV/cm in the optimal composition of x = 6, accompanied by an enhanced dielectric temperature stability meeting the requirement of wider working window. In addition to good frequency, anti-fatigue and temperature stability, the BNBSTC + 6BST ceramics exhibit tremendous potential for designing low-voltage driven energy storage ceramic capacitors. [ABSTRACT FROM AUTHOR]

Pulsed power and power electronics systems used in electric vehicles (EVs) demand high-speed charging and discharging capabilities, as well as a long lifespan for energy storage. To meet these requirements, ferroelectric dielectric capacitors are essential. We prepared lead-free ferroelectric ceramics with varying compositions of (1 − x)Ba0.7Sr0.3TiO3–(x)BiMg0.5Ti0.5O3 (BST–BMT) (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1) using a solid-state-reaction method. To analyze the crystallinity and structural parameters, we examined the X-ray diffraction (XRD) patterns using the pseudo-Voigt function in the FullProf software. Additionally, Raman spectrum analysis confirmed the presence of ceramic structural distortion caused by microstrain and doping. Microstructure images of the ceramic samples showed an increase in grain size from 1 to 2.4 μm and an improved distribution of grain sizes with increasing doping levels. We investigated the dielectric properties of the BST–BMT ceramic capacitors across a wide range of frequencies and temperatures. Interestingly, as the BMT content increased, the previously saturated ferroelectric (FE) curve for x = 0.01 gradually shifted towards a narrower relaxor ferroelectric (RFE) curve for x = 0.1. The most favorable effective energy storage density was observed with a BMT doping concentration of x = 0.04, which coincided with exceptionally high-energy efficiency (η ~ 91%) under a field strength of 50 kV/cm and a relatively high dielectric normalized energy storage density of 3.71 µJV−1 cm−2 due to structural modifications that causes relaxor ferroelectric behavior. More interestingly, the energy storage performance of 0.96BST–0.04BMT displays a fatigue free characteristic enduring through numerous switching cycles. We also calculated the optical bandgap (Eg) values from UV–Vis spectra and compared them with the increase in BMT concentration. The Eg value for all ceramics was approximately 3.2 eV, similar to the pure BST ceramic sample. Additionally, the resistive switching behavior demonstrated by our bulk ceramic capacitors is not commonly observed in other bulk ceramics. [ABSTRACT FROM AUTHOR]

In this research, non-stoichiometric Bi doped SrTiO 3 (ST) ceramics with nominal chemical formula of Bi x Sr 1-x TiO 3 (x = 0, 0.01, 0.03, 0.05, 0.07) were produced through a conventional solid-state reaction route. A giant permittivity (ε) ∼30000 and low dielectric loss (tan δ) ∼0.03 were obtained in Bi 0.05 Sr 0.95 TiO 3 ceramic. The temperature- ε and frequency- ε plots were conducted to investigate dielectric properties of the ceramics. The results of dielectric property plots revealed that the Bi 0.05 Sr 0.95 TiO 3 ceramic has excellent dielectric stability within the range of 103–106 Hz and 30–250 °C. The fine scan XRD analysis, X-ray photoelectron spectrometer (XPS) and first principles calculation results showed that giant permittivity property of the Bi 0.05 Sr 0.95 TiO 3 ceramic maybe attributed to the Bi ' Ti − V O ∙ ∙ − Bi ' Ti defect dipoles caused by Bi anti-occupation doping. And the gradient interface formed by Bi excessive doping also contributed to the giant permittivity. This study offers a new approach for achieving a giant permittivity with low dielectric loss in ST ceramic capacitors. [ABSTRACT FROM AUTHOR]

Lead-free dielectric ceramic capacitors are extensively studied for their environmental protection and excellent electrical properties. In this study, (1- x) Bi 0.47 Na 0.47 Ba 0.06 TiO 3 - x MgTiO 3 was synthesized by the classical solid-phase method. Perovskite materials usually have a complex structure, and the modification of the A-site and B-site doping can have a wonderful effect on the material. The effect of A-site Mg2+ doping on the phase structure and electrical properties of (1- x)BNBT- x MT was studied. Results showed that a wider optical band gap and a higher grain boundary density can be obtained by doping at the A-site, which greatly improved the breakdown electric field of the ceramics. X-ray diffraction, Raman scattering, transmission electron microscopy, and dielectric constant curves of (1- x)BNBT- x MT ceramics were also performed to characterize the transition between rhombohedral and tetragonal phases. The findings indicated that that doping at the A-site successfully induced the polar nanoregion, and the 0.94Bi 0.47 Na 0.47 Ba 0.06 TiO 3 -0.06MgTiO 3 relaxation ferroelectric ceramics had high W rec (5.82 J/cm3), stable frequency (W rec = 2.53 J/cm3±3 %, 1–200 Hz), excellent temperature stability (W rec ≈2.37 ± 3 % J/cm3, 30–100 °C), and fast discharge rate (4μs). This work can provide ideas for the development of green and harmless dielectric capacitors with high charge/discharge rate and high energy-storage density. [ABSTRACT FROM AUTHOR]

Highlights: Achieving ultrahigh energy-storage density (7.19 J cm−3) and outstanding storage efficiency (93.8%) at 460 kV cm−1 in BNT-based relaxor ferroelectric ceramics under a moderate electric field. Superior energy-storage performance accomplished through meticulous regulation of permittivity, enhancement of insulation quality, and strategic domain engineering via chemical formula optimization. The intricate structure–property relationship elucidated with precision using high-resolution transmission electron microscopy. The increasing awareness of environmental concerns has prompted a surge in the exploration of lead-free, high-power ceramic capacitors. Ongoing efforts to develop lead-free dielectric ceramics with exceptional energy-storage performance (ESP) have predominantly relied on multi-component composite strategies, often accomplished under ultrahigh electric fields. However, this approach poses challenges in insulation and system downsizing due to the necessary working voltage under such conditions. Despite extensive study, bulk ceramics of (Bi0.5Na0.5)TiO3 (BNT), a prominent lead-free dielectric ceramic family, have seldom achieved a recoverable energy-storage (ES) density (Wrec) exceeding 7 J cm−3. This study introduces a novel approach to attain ceramic capacitors with high ESP under moderate electric fields by regulating permittivity based on a linear dielectric model, enhancing insulation quality, and engineering domain structures through chemical formula optimization. The incorporation of SrTiO3 (ST) into the BNT matrix is revealed to reduce the dielectric constant, while the addition of Bi(Mg2/3Nb1/3)O3 (BMN) aids in maintaining polarization. Additionally, the study elucidates the methodology to achieve high ESP at moderate electric fields ranging from 300 to 500 kV cm−1. In our optimized composition, 0.5(Bi0.5Na0.4K0.1)TiO3–0.5(2/3ST-1/3BMN) (B-0.5SB) ceramics, we achieved a Wrec of 7.19 J cm−3 with an efficiency of 93.8% at 460 kV cm−1. Impressively, the B-0.5SB ceramics exhibit remarkable thermal stability between 30 and 140 °C under 365 kV cm−1, maintaining a Wrec exceeding 5 J cm−3. This study not only establishes the B-0.5SB ceramics as promising candidates for ES materials but also demonstrates the feasibility of optimizing ESP by modifying the dielectric constant under specific electric field conditions. Simultaneously, it provides valuable insights for the future design of ceramic capacitors with high ESP under constraints of limited electric field. [ABSTRACT FROM AUTHOR]

TiO 2 -based ceramics have application potential in multilayer ceramic capacitors because of its large dielectric constant and low dielectric loss. In this work, Cu2+, Nb5+ co-doped TiO 2 ceramics (CNTO) with colossal permittivity and low loss were designed and prepared via an oxide mixed method, and the effect of Cu2+, Nb5+ co-doped amount on dielectric properties were systematically investigated. Remarkably, the compositions of (Cu 1/3 Nb 2/3) 0.005 Ti 0.995 O 2 and (Cu 1/3 Nb 2/3) 0.01 Ti 0.99 O 2 exhibit large dielectric permittivity (ε r) of ∼27,060 and ∼41,200 accompanied with low dielectric loss (tan δ) of ∼0.011 and ∼0.032 at 1 kHz, respectively. Based on dielectric properties, relaxation behavior assessments and X-ray photoelectron spectroscopy analysis, we confirmed that the high dielectric permittivity of CNTO ceramics mainly originates from the electron-pinned defect-dipole (EPDD) effect. Moreover, the temperature stability value of ε r keeps stable of ±7.5% at 1 kHz from −200 to 200 °C for (Cu 1/3 Nb 2/3) 0.005 Ti 0.995 O 2 and from 10 to 200 °C for (Cu 1/3 Nb 2/3) 0.01 Ti 0.99 O 2 ceramics, which separately meet the X9F and Z9F capacitor requirements, respectively. The findings presented in this work might have important strategic significance for promoting the miniaturization of electronic components. [ABSTRACT FROM AUTHOR]

Eco-friendly dielectric energy-storage ceramics capacitors are extremely urgent for pulsed power system applications. Unfortunately, it is a grand challenge to boost the energy-storage properties. In this study, we make use of a composition driven strategy to refine microstructures, enhance dielectric relaxation, and adjust phases composition of (1- x) (Na 0.47 Bi 0.47 Ba 0.06)TiO 3 - x Ba(Mg 1/3 Ta 2/3)O 3 lead-free ceramics. The results showed that all the sintered samples owned a perovskite structure, and dense microstructure. Furthermore, with Ba(Mg 1/3 Ta 2/3)O 3 doping level increasing, the peak of ε r shifts to a lower temperature, and becomes boarder. Interestingly, the superior recoverable energy density (W rec)⁓5.9 J/cm3 and energy efficiency (η) ⁓82.3% values are simultaneously received for the x = 0.14 ceramic, respectively. Moreover, the above sample also illustrates positive temperature (25–120 °C) and frequency (1–500 Hz) energy-storage stabilities. Meanwhile, a power density of 59.2 MW/cm3, as well as a discharge speed time of 199 ns are also obtained in the x = 0.14 ceramic. It is believed that this work will give a helpful guideline for the promotion of Na 0.5 Bi 0.5 TiO 3 lead-free dielectric ceramics capacitors. [ABSTRACT FROM AUTHOR]

Dielectric ceramic capacitors with superior energy storage efficiency and ability to operate in high temperature environments (T ∼200 °C) are urgently needed for practical application. In this study, a relaxor component of Bi(Zn 2/3 Nb 1/3)O 3 (BZN) was massively doped into Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 (BCZT) ceramic to improve energy storage properties and ability to operate in high temperature. The massive introduction of Bi(Zn 2/3 Nb 1/3)O 3 optimizes dielectric relaxor behavior, enhances bandgap width, refines grain size and improves electrical homogeneity, which can significantly increase breakdown strength (E b), decrease remanent polarization (P r) and broaden dielectric constant peak. Here, the 0.75BCZT-0.25BZN ceramic possesses an ultrahigh energy storage efficiency (∼96.8%) with a large recoverable energy density (∼2.39 J/cm3) under a medium applied field (260 kV/cm). In addition, the optimum sample exhibits prominent thermal stability within 20∼200°C and dielectric temperature stability (Δ C / C 25°C ≤ ± 15%, −63∼234°C) in accordance with X9R. More critically, the same composition was firstly measured fatigue endurance at 200°C and possesses excellent fatigue stability. The above results demonstrate that the optimum sample has potential for practical application in high temperature environments. [ABSTRACT FROM AUTHOR]

Modified BaTiO3 ceramics that possess high dielectric permittivity and acceptable temperature stability have been widely utilized as multilayer ceramic capacitors (MLCCs) for high‐frequency bypass and power filtering in automotive applications. However, since the increasing demand for high‐capacity and small‐size, high‐permittivity materials that can serve as dielectric layers in MLCCs are urgently required. In this work, we design and fabricate a special BaTiO3‐0.03Mg‐0.02Y‐0.02CaZrO3 ceramic with a high dielectric permittivity of 3000 and the dielectric variation below ±13% in the temperature range of ‐55–150°C, fulfilling the requirements of X8R capacitors. To achieve these results, we employed grain size engineering and cation doping, using BaTiO3 precursors with a particle size of 240 nm to prepare the BaTiO3‐based ceramics with fine grains, while Mg and Y co‐doping was used for improving the temperature stability due to dielectric dispersion. Utilizing these high‐permittivity BaTiO3‐based materials, we fabricated MLCCs that satisfy the X8R criterion, possessing a high dielectric constant of 2950 and a high breakdown field (410 kV/cm). [ABSTRACT FROM AUTHOR]

Bismuth potassium titanate (Bi 1/2 K 1/2)TiO 3 -based relaxor ferroelectrics are promising materials for high-energy-density ceramic capacitors. Herein, we compare the microstructure and energy-storage properties of (Bi 1/2 K 1/2) 0.5 Sr 0.5 TiO 3 (BKST50) ceramics fabricated via two different routes: solid-state and hydrothermal reactions. A BKST50 fine powder composed of well-dispersed cubic nanoparticles was obtained via the hydrothermal reaction, whereas the conventional solid-state reaction resulted in the aggregation of primary particles. The grain size of the ceramics prepared from the hydrothermal powder could be controlled between 273 ± 24 and 936 ± 69 nm while maintaining a relative density of over 95% by simply varying the sintering temperature. On the other hand, ceramics prepared via the solid-state reaction could not be fully densified even at 1200 °C (the highest tested sintering temperature). The hydrothermally derived ceramics withstood higher electric field owing to dense and fine-grained microstructure, leading to a high recoverable energy-storage density of 2.25 J cm−3 at 240 kV cm−1. [ABSTRACT FROM AUTHOR]

In general, NaNbO3 (NN) ceramics are considered to be one of the most promising lead-free perovskites (AFE) materials with low cost, low density, and nontoxic advantages. However, the energy storage capability of this material is often greatly hindered by the hysteresis exhibited during the transition from the antiferroelectric to the ferroelectric phase. In this study, lead-free dielectric (1−x)NaNbO3−xBi(Li1/3Sn2/3)O3, x = 0.0 − 0.08, ceramics were synthesized by solid-state reaction method. The XRD data show a structural change from orthorhombic to pseudo-cubic at x = 0.06 composition. With increasing Bi(Li1/3Sn2/3)O3 content, changes in dielectric properties demonstrated that the AFE P phase was successively replaced by the relaxor AFE R phase, resulting in a thin P–E loop characteristic which leads to the improvement of the energy storage density and efficiency of the ceramic capacitors. The optimum recoverable energy storage density (Wrec = 0.56 J/cm3) and efficiency (η = 74%) were obtained at x = 0.06 under an electric field of 120 kV/cm. The optimum composition also exhibited temperature stability in the range of 25 °C–100 °C. In addition, an increase in Bi(Li1/3Sn2/3)O3 content can lead to a decrease in leakage current density. This research shows that BLS modified NN ceramics are promising dielectric material candidates for energy storage applications. [ABSTRACT FROM AUTHOR]

Due to the high demand for dielectric materials with high energy density, the energy storage performance of antiferroelectric ceramic capacitors has always gained much attention. Polarization intensity is a key factor that is closely related to the energy storage density. However, thus far, there has been a lack of research studies or successful methods to effectively modulate polarization intensity. The behavior of the polarization process is complex and contains domain nucleation, growth, and flip-flapping. Based on this finding, the introduction of Nb5+ at the B-site was designed to influence the three stages of antiferroelectric polarization by regulating the balance between the ferroelectric and antiferroelectric phases, and eventually realized regulation of the saturation polarization intensity in the (Pb 1-1.5x La x)(Zr 0.5 Sn 0.43 Ti 0.07)O 3 antiferroelectric ceramics. The saturation polarization intensity has increased from 25.56 to 42 μC/cm2 with Nb5+ content increases from 0 to 4 mol% and the hysteresis was kept low, Pb 0.94 La 0.04 (Zr 0.65 Sn 0.35) 0.975 Nb 0.02 O 3 is the optimal component with a high releasable energy density of 8.26 J/cm3 and an energy storage efficiency of 90.31%. This work provides an in-depth explanation of the microscopic mechanism of antiferroelectric ceramic polarization and presents a novel approach for the composition design of high-energy storage density antiferroelectric ceramics. [ABSTRACT FROM AUTHOR]

Today's healthcare system relies on magnetic resonance imaging (MRI) for early diagnosis and treatment planning. For open MRI systems to achieve resolutions of about a hundred microns, a high voltage is required, as well as a specialized power supply. Negative–positive–zero (NP0) ceramic is selected for the fabrication of adjustable capacitors. Specifically, it stands for which is a classification based on the temperature coefficient of capacitance (TCC) of the ceramic material used in the capacitor. NP0 capacitors have a TCC of 0 ±30 ppm/°C, which means that their capacitance value does not change significantly with temperature and frequency. They are known for their stability and low losses, making them ideal for applications that require high accuracy and reliability, such as timing circuits for radio frequency (RF) applications. Here, MgTiO3–CaTiO3 ceramic is used to make an adjustable capacitor with desired properties for MRI systems. To enhance the dielectric properties of MgTiO3 ceramics, CaTiO3 was added in varying concentrations. After pressing and sintering, the resulting samples were tested using a vector network analyzer in the frequency range of 10–130 MHz. The adjustable capacitor fabricated using high co‐fired NP0 ceramic may have been used for MRI applications such as tuning circuits and matching networks, where precise capacitance values and low loss are critical. MRI systems with resonance frequencies of 128 MHz require trimmers with ceramic cores (VBreakdown = 3 kV @ 128 MHz, Cmin = 3 pF, CMax = 30 pF, and Cvariation step = 1.5 pF). [ABSTRACT FROM AUTHOR]

In this study, (1- x)Ca 0.5 Sr 0.5 TiO 3 - x SmNbO 4 ceramics were synthesized using the solid-phase reaction method at 1400 °C. The addition of SmNbO 4 led to significant improvements in breakdown strength (510 kV/cm) and energy storage performance (5.43 J/cm3 and 95.1%), which is the best among linear dielectrics at present. The effects of SmNbO 4 on charge transport and interfacial polarization behavior were investigated. Furthermore, ceramics capacitor exhibits an excellent power density of 36.7 MW/cm3 in an ultrafast discharge time of 29 ns at 140 kV/cm. Meanwhile, x = 0.005 ceramics exhibited good temperature (20 °C–170 °C) and frequency stability (1 Hz–100 Hz). [ABSTRACT FROM AUTHOR]

BaTiO 3 ceramics doped with different contents of Co 2 O 3 (abbreviated as (1-x) BT-xCo 2 O 3) and (1-x) BaTiO 3 -xBiCoO 3 (abbreviated as (1-x) BT-xBC) ceramics were prepared via conventional solid-state process and sintered in reducing atmosphere. The main crystal phase of both ceramic samples was characterized by X-ray diffraction (XRD), which was perovskite structure. Compared with (1-x) BT-xCo 2 O 3 , (1-x) BT-xBC ceramic samples were dense with uniform microstructure confirmed by scanning electron microscopy (SEM). The 0.95BT-0.05BC ceramics had good dielectric properties, with ε 25°C = 2670, tanδ = 0.012, and resistivity was 1.71 × 1011 Ω cm at 25°C, meeting the X7S standard for multilayer ceramic capacitor (MLCC) applications. The mechanism of improved anti-reduction property of (1-x) BT-xBC ceramics was studied by X-ray photoelectron spectroscopy (XPS) and thermally stimulated depolarization current (TSDC) techniques. The XPS results showed that there were two valence states of Co in 0.95BT-0.05BC and 0.95BT-0.05Co 2 O 3 ceramics, indicating that the introduction of Co can improve anti-reduction property of BT-based ceramics. The TSDC revealed the formation of defect dipoles [ 2 C o T i ' − V o ▪ ▪ ], which was considered to be the cause for the improvement in anti-reduction property. [ABSTRACT FROM AUTHOR]

0.96BaTiO 3 -0.04Bi(Mg 1/2 Ti 1/2)O 3 (0.96BT-0.04BMT) + y wt.% Nb 2 O 5 ceramics (0.0 ≤ y ≤ 2.0) were sintered at 1275 °C to fabricate a ceramic with a large ε r for an X8R multilayer ceramic capacitor (MLCC). Addition of Nb 2 O 5 afforded a core–shell structure, and the compositions of the core and shell regions were similar to those of BT and BT-BMT, respectively. The sample (y = 1.25) exhibited a large ε r of 2285 with a good temperature stability satisfying the X8R specification because of a broad shell-region phase-transition peak at −17 °C and a decreased ε r of the core-region phase-transition peak. The 0.1 wt% BaO–CaO–SiO 2 (BCS) was used to reduce the sintering temperature, and the 9-layered MLCC produced using a BCS-doped 0.96BT-0.04BMT + 1.25 wt% Nb 2 O 5 ceramic at 1200 °C showed a large capacitance of 67 nF with a good temperature stability thus complying with EIA-X8R regulations. [ABSTRACT FROM AUTHOR]