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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 dielectric and energy storage properties of (1- x)(0.7(Bi 0.5 Na 0.5)TiO 3 -0.3(Sr 0.7 Bi 0.2)TiO 3)- x Bi(Mg 0.5 Zr 0.5)O 3 (BNT-SBT- x BMZ) ceramics are systematically investigated, and further modified by using the strategy of doping two kinds of sintering aids, LiF and B 2 O 3 –Bi 2 O 3. The results show that all ceramics exhibit a typical perovskite structure. The doping of sintering aids reduces the sintering temperature effectively to below 1000 °C and obtains the dense microstructure. Meanwhile, the ferroelectric long-range order can be disrupted that facilitates the polarization in nano-regions at high temperatures induced by LiF dopants, which enhance the relaxor behavior and form a dielectric platform together with low dielectric loss in a wide temperature range. In addition, extremely slender polarization-electric field (P - E) hysteresis loops are gained by doping LiF in BNT-SBT- x BMZ ceramics associated with an almost non-polar phase that exhibits linear response. In comparison, little change in shape of P - E loops is observed when adding B 2 O 3 –Bi 2 O 3. As a result, outstanding energy storage performances are achieved in sintering-aids modified ceramics under the relatively low electric fields of 180 kV/cm −210 kV/cm. This work provides the optimized energy storage properties and dielectric stability of BNT-based ceramics at reduced sintering temperatures, and pave the way for the cofiring with base metal electrodes in multilayer ceramic capacitors. [ABSTRACT FROM AUTHOR]

dielectric capacitors are highly desired in advanced high-power electrical systems owing to their fast charge-discharge capabilities, such as electromagnetic devices, high-power microwaves, and hybrid electric vehicles. While the performance of dielectric capacitors is mainly dominated by dielectric materials. (Na 0.5 Bi 0.5)TiO 3 -(Sr 0.7 Bi 0.2)TiO 3 (NBT-SBT) as well-known dielectric ceramics attracted much attention and are widely studied owing to their combining antiferroelectric and relaxor features which achieve high energy density and efficiency. However, few studies report the compositional modification of B-site in NBT-SBT dielectric ceramics. Here, we prepared a series of MgNb 2 O 6 doped NBT-SBT ceramics at B-Sites of the perovskite structure. Their phase structure, microstructure morphology structure, elemental distribution, dielectric and energy storage properties are systemically investigated. The resultant characterization showing minor doping MN into NBT-SBT ceramic decreases the polarization hysteresis generating an outstanding energy storage property. In addition, their energy-density variation of less than 10 % over a wide temperature range of −50 to 150°. The present research offers a route for designing dielectric ceramics with enhanced energy storage performance. • Synthesized pure phase NBT-SBT ceramics with varying MgNb 2 O 6. • Small additions of MgNb 2 O 6 reduced polarization hysteresis while boosting energy storage potential. • Achieved a 1.5 J cm⁻1 energy storage density with stable efficiency (83–95 %) and less than 10 % fluctuation. [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]

High-performance dielectric energy-storage ceramics are indispensable core components in pulsed power systems. Despite progress in enhancing energy storage performance, there are still significant constraints among various macroscopic performance parameters, hindering their miniaturization and integration into devices. Herein, we propose a novel weakly coupled relaxor ferroelectric ceramic system that delays premature polarization saturation of BaTiO 3 -based ceramics to achieve the desirable energy storage characteristics. The ceramic exhibits a high energy storage density (W rec) of ∼4.58 J cm−3 and high energy efficiency (η) of ∼95.2 % under an electric field of 540 kV cm−1, along with good performance stability in the range of 40–160 °C and 1–120 Hz. Furthermore, the enhanced insulation properties and refined average grain size contribute to the high breakdown field strength (E b) of the system. These findings provide a viable framework for the design of dielectric ceramic capacitors with high energy-storage characteristics. [ABSTRACT FROM AUTHOR]

(1-x) (Na 0.2 K 0.8)NbO 3 -xSrTiO 3 [(1-x) (N 0.2 K 0.8)N-xST] ceramics with a homogeneous perovskite structure were well-sintered in the range of 1080–1160 °C. The 0.9(N 0.2 K 0.8)N-0.1ST ceramic was found to have a temperature-stable dielectric constant (ε r) that complies with the X9R multilayer ceramic capacitor (MLCC) requirement. The temperature stability of the ε r value was also investigated for the 0.9(N 1-z K z)N-0.1ST ceramics (0.0 ≤ z ≤ 1.0). The results indicated that as z (or K+ ions) increased, the Curie temperature (T C) decreased, and its peak broadened. The broadening of the T C peak was attributed to the development of the relaxor property owing to the tilting of the NbO 6 octahedra. The 0.9(N 1-z K z)N-0.1ST ceramics (0.7 ≤ z ≤ 1.0) exhibited a temperature-independent ε r value, thus fulfilling the X9R MLCC requirement because of the broad T C peak. The MLCC fabricated from 0.9(N 0.2 K 0.8)N-0.1ST thick films complied with the X9R MLCC requirement with excellent capacitance stability under the supplied electric field. Hence, 0.9(N 1-z K z)N-0.1ST ceramics (0.7 ≤ z ≤ 1.0) are good candidates for X9R MLCCs. [ABSTRACT FROM AUTHOR]

Highly accelerated lifetime test (HALT) for lifetime evaluation was performed on the state-of-art automotive MLCC prototypes by varying Dy/Mg (donor/acceptor) ratio added to BaTiO 3. The results clearly showed that the mean time to failure (MTTF) more than 280 times as the Dy/Mg ratio increased from 1.0 to 10.0. Since oxygen vacancies typically form in-gap state/defect at the donor level, the activation energy value under thermal activation process as a function of voltage was calculated and compared by non-destructive testing (I – V curve) for an accurate evaluation of the extrinsic behavior. It was found that barrier height at the Ni/BT interface decreases as the voltage increases, resulting in a decrease in activation energy. As the Dy/Mg ratio increases, the density of defects/in-gap states formed at the donor level in the bandgap by oxygen vacancies decreases, which may lead to a decrease in the number of electrons excited by the external voltage. Furthermore, it was verified that the calculated Schottky barrier height of the 10.0 Dy/Mg ratio under voltage has higher value than that of the 2.6 Dy/Mg ratio. Based on the results of this study, we propose a new indicator for the design of automotive MLCCs with high lifetime reliability that can be used for comparative analysis of additive compositions through non-destructive test (I – V curve) with low evaluation time/cost. [Display omitted] [ABSTRACT FROM AUTHOR]

Relaxor ferroelectric ceramics are extremely encouraging materials for energy storage capacitor applications in pulse equipment. As the second largest ferroelectric ceramic system, tungsten bronze structure relaxor ferroelectric ceramics have emerged as a significant contender and garnered significant attention in the pulse capacitor research field. In this work, an Sb-modified Sr 2 KNb 5 O 15 -based tungsten bronze relaxor ferroelectric ceramic system is designed to explore its energy storage potential. XRD refinement reveals the declines in the oxygen octahedra tilting and distortion after the introduction of Sb, which significantly augments the relaxation behavior. Additionally, refined grain size and reduced oxygen vacancy concentration are observed, greatly improving the breakdown strength. Consequently, a superior energy storage density (∼4.57 J/cm3) accompanied by wonderful energy storage efficiency (∼89.3 %) is received at 540 kV/cm, with wide frequency stability and great thermal stability. Moreover, amazing discharging performances are also achieved with rapid discharge speed (τ 0.9 < 70 ns), towering discharge current density (815.2 A/cm2) and surprising power density (130.4 MW/cm3). All these performances indicate that the designed Sr 2 KNb 5 O 15 -based tungsten bronze relaxor ferroelectric ceramic can be one encouraging option in the dielectric energy storage field. [Display omitted] [ABSTRACT FROM AUTHOR]

BaTiO 3 -based ceramic is considered to be a fascinating dielectric material with high reliability for ultra-thin multilayer ceramic capacitors (MLCC). Here, we fabricated a series of acceptor-doped BaTiO 3 (Mg: 0.2, 0.5, 1.0, 1.5, 2.0, and 5.0 mol%) ceramics with Al 2 O 3 and SiO 2 as sintering additives. With an increase in Mg concentration, the insulation resistance of the BaTi 1- x Mg x O 3 ceramics initially increases and then decreases, in which the 0.5 mol% Mg-doped ceramic achieves superior degradation behavior. The reason is that with the incorporation of the acceptor ion Mg2+, the charge compensation mechanism in the system changes. Initially, barium vacancy is generated, which is gradually dominated by oxygen vacancy. Analysis indicates that the segregation of the acceptor state barium vacancy to the grain boundary increases the schottky barrier of the grain boundary, while the gradual increase of the donor state oxygen vacancy reduces the reliability of the ceramic. This study provides a comprehensive overview illustrating the significant role of point defects in the potential barrier of the grain boundary in acceptor-doped BaTiO 3 ceramics. It identifies a pathway to achieve high reliability in BaTiO 3 -based MLCC. [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]

Glass frits effectively facilitate the sintering densification to produce high-density terminal electrodes, crucial for achieving high reliability of MLCC (Multilayer Ceramic Capacitors) devices. However, manufacturing terminal electrodes with high density and strong adhesion under low-temperature sintering condition still has enormous challenges. Herein, Na 2 O–BaO–ZnO–B 2 O 3 –SiO 2 glass has been fabricated for low temperature sintering copper paste. We demonstrate that the densification degree and adhesion strength of the terminal electrode can be notably optimized by adjusting the Na 2 O content in the glass frit. The doping of Na+ in glass effectively improves the wettability of the melt on the copper substrate and the surface tension of the glass melt, enhancing the capillary force in the liquid phase sintering process. The rate of electrode densification is accelerated by the increase in capillary force, thus reducing the sheet resistance of copper film from 4.52 to 4.30 mΩ/□. Furthermore, with the increase in the Na+ content, the work of adhesion between glass and ceramic gradually increases, which effectively enhances the shear strength of the electrode from 19.66 MPa to 29.55 MPa. Our work provides novel insights for the design of glass compositions in the field of terminal paste. [ABSTRACT FROM AUTHOR]

Energy storage capacitors for advanced pulse power systems and high-power electric devices is a kind of important electronic components, the demand continues to grow, specifications are constantly being upgraded, and performance boundaries are continuously being pushed. Multilayer ceramic capacitors (MLCCs) for energy storage applications have received increasing attention due to the advantages of ultralow equivalent series inductance, equivalent series resistance, good frequency characteristics, strong voltage overload ability, and stable operability at high temperatures. However, the relatively low energy storage density significantly limits its broader applications. Here, 0.4Ba 0.55 Sr 0.45 TiO 3 -0.4Bi 0.5 Na 0.5 TiO 3 -0.2SrZrO 3 (0.4BST-0.4BNT-0.2SZ) relaxor ferroelectric MLCCs are prepared at different heating rates. Excellent recoverable energy storage density of 10.3 J cm−3 and high energy efficiency of 93 % are achieved in fast-fired MLCCs under the electric field of 106.3 V μm−1. The impedance spectroscopy and thermally stimulated depolarization current technologies are employed to investigate the conductance mechanism of MLCCs, and the results can explain the effect of heating rate on the performance of MLCCs. In addition, the charge-discharge performances of fast-fired MLCCs are also thoroughly investigated, exhibiting great thermal and fatigue stability. [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]

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]

The multi-layer ceramic capacitor (MLCC) is prepared with Bi 1.5 MgNb 1.5 O 7 (BMN) pyrochlores, which has medium dielectric constant, large dielectric tunability, and especially the very small dielectric loss. The multilayer ceramic capacitors with Bi 1.5 MgNb 1.5 O 7 as the dielectric material are prepared by a tape-casting method. The dielectric constant of the BMN thick film was observed to be superior to that of the bulk material, indicating its potential application in electronic devices. The increase in dielectric constant during the preparation of multilayer ceramic capacitors was explained by investigating the interdiffusion between the ceramic thick films and the electrodes. The BMN thick films and Ag 0.7 /Pd 0.3 electrodes showed a dense microstructure and serial interfaces when sintering at 1050 °C for 1.5 h. The capacitor exhibited good temperature stability with a dielectric constant temperature coefficient of −249.94 ppm/°C, a relative dielectric constant of 216, and a dielectric loss of 0.00036. Provides insights for the development and optimization of high-performance dielectric tunable electronic device. [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]

(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]

0.75(0.4Na 2 O-0.1K 2 O-0.5Nb 2 O 5)-0.25(0.87SiO 2 -0.13BaO) glass-ceramics were prepared by a traditional melting method to optimize the crystallization kinetics. We obtained a glass network with high degree of polymerization (DOP) by crystallization at different temperatures and achieved a high energy storage density. The increase of crystallization temperature has promoted the precipitation of ferroelectric phases Na 0.9 K 0.1 NbO 3 and NaNbO 3 with high dielectric constant (1200–2000), promoted the increases of grain size from 0.76 μm to 1.33 μm, and reduced the gap width from 3.71eV to 3.22eV. When the crystallization temperature increased to 1000°C–1100 °C, Ba 2 NaNb 5 O 15 with low dielectric constant (∼460) increases, grain boundaries appear, and dielectric constant and BDS decrease. Among all the samples, the sample crystallized at 900 °C showed homogeneous and dense microstructure (grain size∼0.91 μm). The experimental data confirmed that the glass sample crystallized at 900 °C achieves low dielectric loss (<0.005) and high dielectric constant (∼122). The glass sample crystallized at 900 °C sample had a maximum energy storage density of 3.65 J/cm3, a power density of about 54 MW/cm3 and a super-fast discharge speed of 38 ns at 660 kV/cm. [ABSTRACT FROM AUTHOR]

Future low-voltage driven capacitor devices are appealed to employ the eco-friendly ceramics featured with high-stable dielectric energy storage capabilities. Herein, the dielectric energy storage properties of (Bi 0 · 5 Na 0.5) 0.65 (Ba 0 · 3 Sr 0.7) 0.35 (Ti 0 · 98 Ce 0.02)O 3 +8 wt% K 0 · 5 Na 0 · 5 NbO 3 + x wt% CeO 2 (BNBSTCK + C x) lead-free relaxor ferroelectric ceramics were comprehensively investigated. By maintaining the relaxor ferroelectric phases near room temperature and disrupting the ferroelectric long-range order via CeO 2 additive, the EIA X9R specification was fulfilled at the best composition of x = 8 over a wide range of −74∼208 °C with a relatively high dielectric constant ε r = 904 and low loss tan δ = 10−3 (@25 °C & 1 kHz). Meanwhile, the good recoverable energy storage density W rec = 0.77 J/cm3 and high efficiency η = 91.6% were achieved only at a low electric field of 95 kV/cm. Furthermore, these ceramics exhibited exceptional frequency and cycle dependent energy storage stability, which could guide the design ideas of long-life X9R ceramic capacitors suitable for high and low working temperature environments in low-voltage driven energy storage applications. [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]

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]

Aging in dielectrics manifests as a reduction in capacitance over time owing to the applied electric field. This study revisits the aging mechanism in multi-layer ceramic capacitors (MLCCs), specifically considering DC-bias voltage and temperature variables. The findings indicate that aging is intensified by higher DC-bias voltages (electric field strength) and elevated temperatures, ultimately leading to capacitance saturation. A poling–depoling experiment confirms the rapid assessment of saturation capacitance. Consequently, we propose a straightforward method involving electric field manipulation to quantitatively evaluate the saturated capacitance of MLCCs under aging conditions. The estimated capacitance aligns closely with the measured capacitance after 2000 h, with an error rate not exceeding 4 %. [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]

The demand for robust multilayer ceramic capacitors with high-temperature and high-power capabilities is surging. Cost-effective production is a key challenge, often linked to precious metal electrodes like Pt, Pd, and Ag in multilayer ceramic capacitors (MLCCs). To address this, cost-efficient base metal electrodes such as Cu and Ni are sought. Promising lead-free options are Na 0.5 Bi 0.5 TiO 3 (NBT)-based materials. However, their sintering temperatures exceed Cu's melting point (1085 °C), necessitating sintering aids for compatibility. We investigated several low-temperature sintering aids (Li 2 O, Na 2 O, Bi 2 O 3 , B 2 O 3 , ZnO, and V 2 O 5) to lower the sintering temperature of Na 0.5 Bi 0.5 TiO 3 -BaTiO 3 -CaZrO 3 -BiAlO 3 solid solutions. Results reveal NBT-based materials' sensitivity to acceptor dopant incorporation from sintering aids, impacting electrical properties. Yet, we successfully reduced the sintering temperature to 975 °C, suitable for Cu co-sintering, with minimal adverse effects on capacitor properties using well-tuned sintering aids. [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]

A chemical coating method to form a core-shell structure was applied to produce ZnO@Ba 0.65 Bi 0.07 Sr 0.245 TiO 3 (ZnO@BBST) relaxing ferroelectric ceramics with high energy storage density. The ZnO@BBST ceramic grain was refined and the structure is dense. Simultaneously, the relaxor behavior of ZnO@BBST was improved due to the synergistic effect of ZnO shell and internal BBST. Ultimately, under the electric field of 320 kV/cm, a energy storage density of 1.91 J/cm3 and an energy storage efficiency of 82 % are obtained in 2 wt% ZnO@BBST, together with fast discharge characteristics(τ 0.9 <1.25 μs) and excellent cycle stability (up to 1 × 105 times). ZnO@BBST ceramics have its unique advantages in the field of ceramic capacitors. [ABSTRACT FROM AUTHOR]

In this study, in-situ formation of intermetallic compound (IMC) was proposed to reduce the sintering shrinkage mismatch between Ni electrode and dielectric material for multilayer ceramic capacitors (MLCCs). Tin (Sn) was selected as an alloying element and introduced in the form of SnCl 2 into Ni nanopowder. The Sn precursor was decomposed at ∼450 °C and a cubic Ni 3 Sn intermetallic phase was formed at 500 °C, which was gradually transformed to a hexagonal Ni 3 Sn phase at 700 °C and thereafter thermally decomposed above 800 °C forming the Ni–Sn solid solution. The Sn addition shifted the shrinkage onset temperature of Ni electrode to a higher temperature by 300–400 °C and effectively retarded the low temperature densification through in-situ formation of Ni 3 Sn intermetallics by inhibiting the inter-diffusion between Ni nanoparticles. Furthermore, the sintered Sn added Ni (Ni–3Sn) electrode exhibited an electrical conductivity comparable to that of pure Ni electrode, demonstrating its suitability as an alternative electrode for MLCCs. [ABSTRACT FROM AUTHOR]

Point defects play a versatile role in modulating ferroelectricity and piezoelectricity, however, the decisive role of point-defect concentration/species in controlling macroscopic performance remains unknown. In this work, defects are implanted by reduced atmosphere annealing and/or Mn doping in Pb 0.7 Ba 0.3 ZrO 3 ceramics. i) defects induce lattice distortion, internal lattice strain and accordingly, phase structure is changed (Williamson-Hall analysis and Rietveld refinement); ii) ferroelectricity is enhanced for 0 MN and 1 MA sample with contribution of defect polarization (first-order reversal curves). iii) Joule heat is depressed as an enhanced resistivity by carrier annihilation/forming defect complex; iv) ECE behaves distinctly among 0 MN, 1 MA and 1 MH, respectively. 0 MN sample exhibits a ΔT max of 0.39 K and 1 MA possesses a ΔT max of 0.34 K. Interestingly, a broad temperature span with a low instability of ∼20 % within 288 K–423 K is obtained in 1 MH sample. This work not only provides a guideline for defects enhancing ferroelectricity and ECE, but also clarifies the reduction-resistant properties of (Pb, Ba)ZrO 3 system that are suitable for constructing base-metal multilayer ceramic capacitors in solid-state cooling devices. [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]

Na 0.5 Bi 0.5 TiO 3 (NBT) ceramic is a potential dielectric material for the manufacture of high-performance dielectric ceramic capacitors due to its high polarization and environmentally friendly characteristics. In this work, (1– x)(0.70Na 0.5 Bi 0.5 TiO 3 –0.30SrTiO 3)– x Bi(Ni 0.5 Hf 0.5)O 3 (NBST– x BNH) ceramics have been prepared based on the strategy of refining grain size and inducing polar nano-regions (PNRs). As a result, the NBST–0.15BNH ceramic achieved large energy density and efficiency (W rec = 4.11 J/cm3, η = 82.1%) at a low electric field of 240 kV/cm. This performance is outstanding compared to existing reports at similar breakdown electric fields. The introduction of Sr2+ enabled the NBST to have a high relaxation property, and the introduction of BNH induced PNRs, which ensured the high energy storage efficiency of the ceramics. BNH doping refined grain size, which contributed to the large breakdown electric field strength of the ceramics. In addition, stability tests showed that the NBST–0.15BNH ceramic had excellent thermal and frequency stability. The ceramic also demonstrated a fast discharge rate (t 0.9 = 148 ns) in the charge-discharge test. [Display omitted] [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]

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]

Field-driven transition from antiferroelectric (AFE) to ferroelectric (FE) states has gained extensive attention for microelectronics and energy storage applications. High dielectric-breakdown-strength (DBDS) for a given material is a necessity to attain full capacity of electrical energy storage. An approach to increasing energy performances is to modulate the related materials to own a higher phase transition electric field (E FE-AFE) using elemental dopants. In this case, Cd2+ was selected as the dopant at A-site in the Pb 0.97 La 0.02 Zr 0.50 Sn 0.45 Ti 0.05 O 3 ceramics to tailor this E FE-AFE value due to the ionic difference enhanced antiferroelectricity. Surprisingly, the doped ceramics increased E FE-AFE by half, DBDS by 16 %, and maintained energy storage efficiency η of over 85 %, providing a way to improve energy storage density. It is worth mentioning that while the performance has been improved, the sintering temperature has been reduced by 170 °C. At the same time, the ceramics maintain good temperature stability, extremely fast discharging speed and discharging energy storage density, indicative of a promising choice in pulse power devices. [ABSTRACT FROM AUTHOR]

Dielectric ceramic capacitors have been extensively investigated in electronic and high-power electrical systems due to their high-power density, fast charge-discharge rates, brilliant fatigue endurance, and good high-temperature stability. In this study, the dielectric and energy-storage performance of [(Bi 0.5 Na 0.5)TiO 3 ] (1-x) –[Ba(Ni 0.5 Nb 0.5)O 3 ] x (x = 0, 0.02, 0.03, 0.04, 0.05, and 0.06) relaxor ferroelectric ceramics were investigated as a function of electric field and temperature. The splitting of (200) reflections in the XRD pattern confirmed the rhombohedral phase with R 3 c symmetry of all samples. The scanning electron microscopy confirmed that the average grain size gradually increased with doping. The introduction of BNN reduced the temperature of the ferroelectric-antiferroelectric phase transition (T d) and antiferroelectric - paraelectric phase and enhanced the relaxor behavior of BNT ceramics. The value of the recoverable energy density (W rec) and efficiency (η) increased from 0.049 J/cm3 to 0.627 J/cm3 and 2.13%–61.71% with an increase of x from 0 to 0.06. Further, the W rec values also showed temperature stability with a variation of less than 8% in the range RT-383 K. Hence, the substitution of BNN in BNT positively affects the overall properties and makes it a promising candidate for energy storage application with superior thermal stability. [Display omitted] [ABSTRACT FROM AUTHOR]

Modern electronics highly demand base metal electrode multilayer ceramic capacitors (BME MLCCs) with ultra-thin dielectric layers and high capacitances owing to the trend for miniaturization. The reliability of MLCCs is crucial for practical applications and significantly affected by the lamination process and material defects. However, the detailed relationships between these factors and the reliability of ultra-thin MLCCs remain elusive. In this study, we investigated the influence of different lamination pressures (denoted as S1, S2 and S3) on the microstructure and reliability of BaTiO 3 (BT) based protocol MLCCs with hundreds of layers. Microstructural observations reveal that among the devices, S2 has the highest roughness for both the Ni internal electrode and dielectric layers. Dielectric property investigations show that S1 and S3 meet the X5R standard and the designed capacity of 10 μF while S2 fails to meet the X5R standard at high temperatures. The electron energy loss spectra investigation reveal that oxygen vacancies are asymmetrically distributed on both sides of the Ni-BT interface in the individual dielectric layers, especially for S2, which indicates that one-side pressure lamination from the bar bulk induces sintering differences on the two sides of the dielectric layer. The results from this study indicate that applying an appropriate critical pressure between BT and Ni (S1) is preferable for decreasing the asymmetry and improving the reliability of MLCCs with ultra-thin layers. [ABSTRACT FROM AUTHOR]

In the discussed work, (1-x) BaTiO 3 (BT)-x Bi(Mg 2/3 Nb 1/3)O 3 (BMN) solid-combinations have been synthesized via the solid-state process; and both corresponding dielectric and ferroelectric behavior have been learned for possible Multilayer Ceramic Capacitor (MLCC) applications. The phase confirmation has been identified utilizing X-ray diffraction; and Rietveld refinement technique has been used for structural analysis that unveils the formation of pure perovskite structure of the prepared ceramics. Rietveld refinement results reveal the structural changeover from tetragonal to pseudo-cubic for x≥0.125. Raman spectroscopy measurements confirm the structural phase changes and lattice modifications due to the chemical substitutions. Microstructural analysis has been done with the help of electron micrograph. Dielectric performance of the synthesized (1-x)BaTiO 3 (BT)-xBi(Mg 2/3 Nb 1/3)O 3 (BMN) solid solutions has been examined within a temperature range of 173K–473K at different applied frequencies. A broad phase transition and relaxor character is detected from dielectric investigation. The relaxor behavior has been quantified by the Vogel-Fulcher fitting. The thermal stability of the prepared samples was calculated by means of standard formula of Temperature Coefficient of Capacitance (TCC). Hysteresis loop was undertaken to identify the ferroelectric properties and energy storage capacity. Among all the compositions, x = 0.10 shows good thermal stability, an elevated recoverable energy density; and a remarkable efficiency that makes it suitable for MLCC applications. [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]

Currently, research on capacitor materials for high-temperature and power electronics focuses on achieving new record-breaking limits for dielectric properties or energy storage densities, with little regard for the stability of key parameters during operation or component reliability. While environmental conditions usually do not exceed 300 °C, the voltage ratings of capacitors are still unclear. Within this work, multilayer ceramic capacitors based on lead-free sodium bismuth titanate with AgPd inner electrodes have exhibited exceptional stability of properties and capacitance at high temperatures and voltages during operation. Despite the lack of precise requirements and limits specified by manufacturers and industry, these prototype MLCCs can help to open up the field of high-temperature and power electronics. Their extensive stability of dielectric properties allows for a rather universal application. [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]