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The (electro)chemical stability of undoped and Zn-doped 0.94Na1/2Bi1/2TiO3–0.06BaTiO3 lead-free piezoceramics (NBT–6BT) was studied. For this purpose, the Fermi level at the interface between NBT–6BT and Sn-doped In2O3 (ITO) electrode is varied by gradually reducing the ITO film either by annealing in vacuum or by applying a voltage across a Pt/NBT–6BT/ITO. The chemical and electronic changes are monitored in situ by x-ray photoelectron spectroscopy. The experiments reveal the formation of metallic Bi when the Fermi level is reaching a value of 2.23 ± 0.10 eV above the valence band maximum, while no reduction of Ti is observed. The electrochemical reduction of Bi constitutes an upper limit of the Fermi level at ≈1 eV below the conduction band minimum. High electron concentrations in the conduction band and a contribution of free electrons to the electrical conductivity of NBT–6BT can, therefore, be excluded. The reduction occurs for an ITO work function of 4.2–4.3 eV. As typical electrode materials such as Ag, Cu, Ni, or Pt have higher work functions, an electrochemical instability of the electrode interfaces in ceramic capacitors is not expected. Under the given experimental conditions (350 °C, electric fields <40 V/mm), no degradation of resistance and no enrichment of Na at the interface are observed. [ABSTRACT FROM AUTHOR]

Various impurities have been doped into ferroelectric BaTiO3-based materials, which are used in multi-layer ceramic capacitors, to improve their insulation resistance, reliability, and dielectric properties. However, the relationship between doped impurities and these device properties at the microscopic level remains unexplored. This study investigated the charge states and solubilities of doped impurities (V, Cr, Mn, Fe, Mg, Ca, and Sr) in BaTiO3 using density functional theory. We employed the screened hybrid functional and a rhombohedral lattice model. Owing to a better description of unoccupied states with the hybrid functional, equilibrium charge states and magnetic moments of V, Mn, and Fe impurities were in good agreement with those measured by magnetic susceptibility measurements. Furthermore, impurity levels of transition metal elements were qualitatively consistent with the experimental reports obtained by electron paramagnetic resonance. However, levels of Fe calculated in cubic BaTiO3 did not reproduce those observations. Therefore, a dynamically stable rhombohedral lattice was found to be more suitable than a cubic lattice for calculating the defects in BaTiO3. The solubility of transition metal dopants was highly dependent on the oxygen chemical potential conditions. By analyzing the cohesive energy, we observed a lower (higher) equilibrium charge state of the defect compared with the higher (lower) oxidation number of stable competitive phase enhanced solubility under reducing (oxidizing) conditions. Our calculations revealed that vanadium and manganese dopants were soluble under reducing conditions owing to instabilities of their metal phases and act as effective acceptors in BaTiO3. [ABSTRACT FROM AUTHOR]

Various impurities have been doped into ferroelectric BaTiO3-based materials, which are used in multi-layer ceramic capacitors, to improve their insulation resistance, reliability, and dielectric properties. However, the relationship between doped impurities and these device properties at the microscopic level remains unexplored. This study investigated the charge states and solubilities of doped impurities (V, Cr, Mn, Fe, Mg, Ca, and Sr) in BaTiO3 using density functional theory. We employed the screened hybrid functional and a rhombohedral lattice model. Owing to a better description of unoccupied states with the hybrid functional, equilibrium charge states and magnetic moments of V, Mn, and Fe impurities were in good agreement with those measured by magnetic susceptibility measurements. Furthermore, impurity levels of transition metal elements were qualitatively consistent with the experimental reports obtained by electron paramagnetic resonance. However, levels of Fe calculated in cubic BaTiO3 did not reproduce those observations. Therefore, a dynamically stable rhombohedral lattice was found to be more suitable than a cubic lattice for calculating the defects in BaTiO3. The solubility of transition metal dopants was highly dependent on the oxygen chemical potential conditions. By analyzing the cohesive energy, we observed a lower (higher) equilibrium charge state of the defect compared with the higher (lower) oxidation number of stable competitive phase enhanced solubility under reducing (oxidizing) conditions. Our calculations revealed that vanadium and manganese dopants were soluble under reducing conditions owing to instabilities of their metal phases and act as effective acceptors in BaTiO3. [ABSTRACT FROM AUTHOR]

The degree of microstructural non-uniformity and the lifetime extension of multilayer ceramic capacitors (MLCCs) were evaluated by repeating the fabrication of "prebreakdown" MLCCs through highly accelerated life tests (HALTs), the removal of the insulation resistance-degraded layer, and the reformation of the terminal electrode. The total mean time to failure (MTTF) tended to extend and converge as HALTs were repeated. Microstructural analysis in the degraded local area revealed a clear correlation between the shorter lifetime and the minimum number of grains per unit dielectric layer. After HALTs were repeated, the number of grains came close to and converged as much as undegraded areas over a longer lifetime. These results imply that degradation occurs in order from the greatest degree of microstructural non-uniformity and that the weakest-link model can be understood by treating the lifetime as MTTF. [ABSTRACT FROM AUTHOR]

With the developments of the electronic industry, efforts to achieve high DC insulating reliability are underway to improve the mean time to failure (MTTF) of multilayer ceramic capacitors (MLCCs). However, there are few studies on appropriate measuring methods to evaluate their different reliability characteristics quantificationally. This study measured different reliability characteristics of BaTiO 3 -based multilayer ceramic capacitors sintered at three different temperatures with highly accelerated life tests (HALTs). Kaplan–Meier survival analysis, two-parameter Weibull fitting, and a new method using a stud genetic algorithm were used to calculate their MTTF in HALT conditions, and the comparison among them was carried out to select a proper fitting way. With the appropriate method, their MTTF at the rated condition was predicted and compared. Their conduction modes were also differentiated to explain their aging sensitivities to temperature and voltage. As a result, a proper way to evaluate the sample's reliability characteristics with a bathtub curve was established, and the best sintering temperature for capacitance that is also the best for reliability at the rated condition was confirmed. Meanwhile, different conducting models of MLCCs were also proved to be related to their insulation stability. [ABSTRACT FROM AUTHOR]

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]

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]

Next‐generation electrical and electronic systems rely on the development of efficient energy‐storage dielectric ceramic capacitors. However, achieving a synergistic enhancement in the polarization and in the breakdown field strength (Eb) presents a considerable challenge. Herein, a heterogeneous combination strategy involving embedding a high Eb plate‐like pyrochlore phase in a high‐polarization perovskite phase is proposed. The embedded plate‐like pyrochlore increases the breakdown field strength and promotes the dynamic polarization response. Meanwhile, the strong spin–orbit coupling effect of the 5d electrons is conducive to the maintenance of the high polarization value of the perovskite. Consequently, the prepared multilayer ceramic capacitor (MLCC) exhibits an ultrahigh Eb and a high polarization. More specifically, an energy storage density (Wrec) of 14.9 J cm−3 with an efficiency of up to 93.4% is achieved for the optimized pyrochlore/perovskite phase. Furthermore, the MLCCs also exhibits an Wrec of ≈ 7.7 J cm−3 ± 4.5% in the temperature range of −50–180 °C. Therefore, this heterogeneous combination strategy therefore provides a simple and effective method for improving the energy‐storage performances of dielectric ceramic capacitors. [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]

To provide a hold‐up time function in DC‐DC supplies for cell site stations or data centers, using a boost converter with a bulk output capacitor as a front‐end converter stage is a simple and highly cost‐effective solution. However, conventional boost converters with a hard‐switching operation result in low conversion efficiency and increased electromagnetic interference emissions. In this paper, a boost converter with a new non‐dissipative snubber is proposed that only requires two additional diodes, an inductor, and a multilayer ceramic capacitor. The main feature of the proposed snubber is that the components are not located on the main power processing path. This means they only require low ratings, improving cost‐effectiveness. A prototype converter is analyzed, realized, and applied to a 300 W redundant DC‐DC power supply module for a 5G cell base station. © 2024 The Author(s). IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Johnson's approximation is implemented in a finite element code to simulate the electric field dependence of a core–shell microstructure material. We show how the microstructure, based here on a 50:50 volume fraction, influences the measured effective permittivity as a function of applied voltage. Using a Johnson's parameter of β = 1.0 × 1010 Vm5/C3, verified from commercial BaTiO3‐based multilayer ceramic capacitors (MLCC), we show how the microstructure and the difference in core and shell conductivities alter the local fields generated and how this influences the voltage dependence of the effective permittivity. Systems that comprise a conductive core‐like material surrounded by a resistive shell experience little or modest voltage dependence due to the shell material providing shielding to large electric fields within the cores. Conversely, if the core material is more resistive than the shell material, substantial voltage dependence occurs with simulations showing over a 50% decrease in the effective permittivity. These simulations give improved understanding of voltage dependence and provide a method to help guide the design of future materials for MLCCs with improved performance. [ABSTRACT FROM AUTHOR]

Multilayer ceramic capacitors (MLCCs) are one of the most widely used and rapidly advancing chip electronic components for high frequency and high integration applications. It is challenging to develop low‐temperature sintering copper pastes for fabricating MLCC terminal electrodes with high adhesion and reliability. Herein, our work demonstrates a novel SrO‐ZnO‐B2O3‐SiO2 glass as a fluxing agent for lowering the sintering temperature of copper paste to enhance adhesion and reliability for MLCCs. It is found that Sr ions as glass modifiers can not only effectively lower the sintering temperature of the glass to 775°C, but also contribute a promotion to the thermal expansion coefficient, which originates from the conversion of the stable [ZnO4] network into a loose [ZnO6] network. The copper paste containing 12.5 SrO‐32.5 ZnO‐40 B2O3‐15 SiO2 (mol.%) was applied for practical terminal electrode sintering at 775°C, exhibiting a dense surface without cracks, integrated cross‐sectional morphology, and high adhesion force (10.2 LB). Furthermore, MLCCs showed lower square resistance (5.65 mΩ/sq), higher reliability in reflow soldering testing (265°C,110 cm/min), and resistance to soldering heat testing (235 ± 5°C, 30 s). Therefore, this work blazes the trail of preparing a novel low‐melting glass for terminal electrode applicable copper paste for the practical MLCCs industry. [ABSTRACT FROM AUTHOR]

Ceramic capacitors have received great attention for use in pulse power systems owing to their ultra-fast charge–discharge rate, good temperature stability, and excellent fatigue resistance. However, the low energy storage density and low breakdown strength (BDS) of ceramic capacitors limit the practical applications of energy storage technologies. In this work, we present a series of relaxor ferroelectric ceramics (1−x) [0.94 Bi0.5Na0.5TiO3 –0.06BaTiO3]– x Sr0.7Bi0.2TiO3 (1-x BNT-BT- x SBT; x = 0, 0.20, 0.225, 0.25, 0.275 and 0.30) with improved energy storage performances by combining relaxor and antiferroelectric properties. XRD, Raman spectra, and SEM characterizations of BNT-BT-SBT ceramics revealed a rhombohedral–tetragonal phase, highly dynamic polar nanoregions, and a reduction in grain size with a homogeneous and dense microstructure, respectively. A high dielectric constant of 1654 at 1 kHz and low remnant polarization of 1.39 µC/cm2 were obtained with the addition of SBT for x = 0.275; these are beneficial for improving energy storage performance. The diffuse phase transition of these ceramics displays relaxor behavior, which is improved with SBT and confirmed by modified the Curie–Weiss law. The combining relaxor and antiferroelectric properties with fine grain size by the incorporation of SBT enables an enhanced maximum polarization of a minimized P-E loop, leading to an improved BDS. As a result, a high recoverable energy density Wrec of 1.02 J/cm3 and a high energy efficiency η of 75.98% at 89 kV/cm were achieved for an optimum composition of 0.725 [0.94BNT-0.06BT]-0.275 SBT. These results demonstrate that BNT-based relaxor ferroelectric ceramics are good candidates for next-generation ceramic capacitors and offer a potential strategy for exploiting novel high-performance ceramic materials. [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 demand for high-power electronic applications is set to drive the necessity for robust components like multi-layer ceramic capacitors (MLCCs). These MLCCs must endure a broad temperature range and withstand high electric fields. Simultaneously, the production cost of these components is a crucial concern for manufacturers. The regularly used Ag/Pd inner electrodes constitute the most significant cost factor. Hence, this study showcases the fabrication of a sodium bismuth titanate (NBT)-based MLCC using only Ag inner electrodes. This could be achieved by reducing the sintering temperatures with the help of sintering aids, but still maintaining excellent dielectric properties of the ceramic. This MLCC demonstrates an exceptional operational temperature range (− 90 to 310 °C), high energy density (up to 5.1 J/cm3), higher efficiency (92%) at 217 kV/cm, and robust capacitance stability (variation less than 10%) even under high temperatures and electric fields. [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]

Despite being the key component in modern electronic devices or power systems, ceramic dielectric capacitors have drawbacks like low energy storage density and efficiency that limit their extensively wide application. This work adopted a different route to improve energy storage performance compared with the frequently utilized composition modification. 0.98Ba0.65Sr0.245Bi0.07TiO3‐0.02Ce Pb‐free ceramics with different polyvinyl alcohol (PVA) contents were prepared through viscous polymer processing. The rheological and energy‐storing performance were systematically studied. It can be seen that high PVA content results in more pores and larger grain sizes that will deteriorate the breakdown strength of ceramics. The highest breakdown strength reached 420 kV/cm while the concentration of PVA was 5 wt%. The mechanism of grain sizes on breakdown strength is studied by electrical tree simulation based on COMSOL. Viscous polymer processing with proper PVA content is very effective in generating dense and homogenous structures. Finally, the ceramic with 5 wt% PVA possesses a high density of up to 4.41 J/cm3 and an efficiency of about 84.21% at 420 kV/cm. Simultaneously, this ceramic improved stability of both temperature (30–150°C) and frequency (1–300 Hz) at 350 kV/cm, while the η kept above 90% and Wrec exceeding 3.6 J/cm3. [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]

Lead‐free ceramic capacitors with high energy storage density are desired. Herein, the novel (1–x)(0.9Bi0.5Na0.5TiO3‐0.1SrTi0.85Zr0.15O3)‐xNa0.95Ca0.04Li0.01Nb0.96Zr0.04O3 [(1–x)(BNT‐STZ)‐xCZNNL, x = 0.1, 0.2, 0.3, 0.4 and 0.5] ceramics are prepared via citrate combustion technology and two‐step sintering method. The dense microstructures are observed and slim hysteresis loops are realized as addition of CZNNL. The enhanced recoverable energy storage density (Wre of 2.52 J cm−3) with high efficiency (η of 80%) is obtained in 0.6(BNT‐STZ)‐0.4CZNNL ceramic under a moderate electric field of 200 kV cm−1. Moreover, excellent thermal stability (Wre varies <1% and η varies <3.5%) at 20 to 100 °C) and excellent fatigue resistance are achieved for 0.6(BNT‐STZ)‐0.4CZNNL ceramic. [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]

Lead‐free ceramic capacitors with high energy storage density are desired. Herein, the novel (1–x)(0.9Bi0.5Na0.5TiO3‐0.1SrTi0.85Zr0.15O3)‐xNa0.95Ca0.04Li0.01Nb0.96Zr0.04O3 [(1–x)(BNT‐STZ)‐xCZNNL, x = 0.1, 0.2, 0.3, 0.4 and 0.5] ceramics are prepared via citrate combustion technology and two‐step sintering method. The dense microstructures are observed and slim hysteresis loops are realized as addition of CZNNL. The enhanced recoverable energy storage density (Wre of 2.52 J cm−3) with high efficiency (η of 80%) is obtained in 0.6(BNT‐STZ)‐0.4CZNNL ceramic under a moderate electric field of 200 kV cm−1. Moreover, excellent thermal stability (Wre varies <1% and η varies <3.5%) at 20 to 100 °C) and excellent fatigue resistance are achieved for 0.6(BNT‐STZ)‐0.4CZNNL ceramic. [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]

Dielectric capacitors, which can achieve tremendous power density and ultrafast charge/discharge speed, are crucial components for high power equipment. Yet, the synchronous achievement in high recoverable energy density (Wrec) and high efficiency (η) is a long‐term difficulty for dielectric ceramics. Herein, the (0.85 − x)NaNbO3–0.15BaTiO3–xBi(Mg1/3Ta2/3)O3 (NN–BT–xBMT) relaxor ferroelectric ceramics were proposed and studied. The doping of BMT was conducive to promoting the microstructure and bandgap and improving the dielectric relaxation properties of NN–BT ceramics. Finally, the sample of x = 0.10 presented a high Wrec of 5.9 J/cm3 and a high η of 90% simultaneously. In addition, the sample also exhibited superb charge/discharge performances with large power density (PD = 137 MW/cm3) and fast charge/discharge speed (t0.9 = 39 ns). The above results reveal that the NaNbO3‐based ceramics could serve as potential alternatives for advanced dielectric capacitors. [ABSTRACT FROM AUTHOR]

A rework of electronic assemblies and the reuse of electronic components are the most effective ways to reduce electronic waste. Since neither components nor substrates were developed with the intention of multiple usage, the question of how the integrity of lead-free solder joints is affected by multiple reflow operations is crucial for the implementation of any reuse strategy. Therefore, various types of 1206 multilayer ceramic capacitors (MLCCs) differing in their capacitance value and dielectric type (X5R, X7R, Y5V, NP0) were soldered on test printed circuit boards (PCBs) having a pure Cu-metallization surface in order to investigate the intermetallic reactions during multiple reflows. The metallization system on the MLCC-component side consisted of a thick film of Ni covered by galvanic-deposited Sn. The reflow experiments were conducted using a hypoeutectic SnAgCu solder. The results show the formation of a Cu6Sn5 intermetallic phase on both metallizations, which grows homogeneously with the number of reflows. Moreover, an ongoing decomposition of the solder into Ag-enriched and depleted zones was observed. The effect of these microstructural changes on the functionality of the solder joint was investigated by mechanical shear experiments and electrical four-point capacitance measurements. [ABSTRACT FROM AUTHOR]

Based on the popularity of intelligent series products, electric vehicles, and portable PCs, the market demand for multi-layer ceramic capacitors (MLCC) has increased extensively. The development of MLCC tends to be of high capacity and small size. Therefore, it is urgent to develop dielectric materials with a wide temperature range and low loss, which is conducive to the operational stability of devices. In this work, (1-x)Ba0.4Sr0.6TiO3-xBi(Mg2/3Nb1/3)O3 (x = 0.20–0.25) ceramics were prepared using a solid-state reaction method. Introducing Bi(Mg2/3Nb1/3)O3 restrains the oxygen loss, reduces the grain size of the sample, breaks the long-range ordered structure, forms polar nanomicroregions, and improves the temperature stability of dielectric materials. Specifically, the sample with x = 0.25 exhibits good dielectric properties (εr = 614, tanδ = 0.0003, at 25 °C and 1 kHz) and high DC resistivity (5.52 × 108 Ω cm) at 300 °C. The dielectric properties of (1-x)BST-xBMN ceramics exhibit good temperature stability in a wide temperature range (− 55 to 200 °C), which meets the requirements of X9R capacitors. [ABSTRACT FROM AUTHOR]

Relaxor ferroelectrics are highly desired for pulse-power dielectric capacitors, however it has become a bottleneck that substantial enhancements of energy density generally sacrifice energy efficiency under superhigh fields. Here, we demonstrate a novel concept of highly polarizable concentrated dipole glass in delicately-designed high-entropy (Bi1/3Ba1/3Na1/3)(Fe2/9Ti5/9Nb2/9)O3 ceramic achieved via substitution of multiple heterovalent ferroelectric-active principal cation species on equivalent lattice sites. The atomic-scaled polar heterogeneity of dipoles with different polar vectors between adjacent unit cells enables diffuse reorientation process but disables appreciable growth with electric fields. These unique features cause superior recoverable energy density of ~15.9 J cm−3 and efficiency of ~93.3% in bulk ceramics. We also extend the highly polarizable concentrated dipole glass to the prototype multilayer ceramic capacitor, which exhibits record-breaking recoverable energy density of ~26.3 J cm−3 and efficiency of ~92.4% with excellent temperature and cycle stability. This research presents a distinctive approach for designing high-performance energy-storage dielectric capacitors. The authors introduce the concept of highly polarizable concentrated dipole glass, involving the reduction of polar order scale from the nanoscaled polar nanodomains in traditional relaxor ferroelectrics to atomic-scale individual dipoles. [ABSTRACT FROM AUTHOR]

Electrostatic energy storage capacitors are essential passive components for power electronics and prioritize dielectric ceramics over polymer counterparts due to their potential to operate more reliably at > 100 ˚C. Most work has focused on non‐linear dielectrics compositions in which polarization (P)/electric displacement (D) and maximum field (Emax) are optimized to give values of energy density, 6≤U≤21 J cm−3. In each case however, either saturation (dP/dE = 0, AFE) or "partial" saturation (dP/dE → 0, RFE) of P limits the value of U which can be achieved before breakdown. It is proposed that U can be further improved with respect to relaxors (RFEs) and anti‐ferroelectrics (AFEs) by designing high permittivity quasi‐linear dielectric (QLD) behaviour in which dP/dE remains constant up to ultrahigh Emax. QLD multilayer capacitor prototypes with dielectric layers composed of 0.88NaNb0.9Ta0.1O3‐0.10SrTiO3‐0.02La(Mg1/2Ti1/2)O3 deliver room temperature U ≈ 43.5 J cm−3, supporting an extremely‐large Emax ≈ 280 MV m−1, both of which exceed current state‐of‐art by a factor of two for devices based on powder, tape‐cast technology. Importantly QLD capacitors exhibit scant variation in U (≈15 J cm−3) up to > 200 ˚C and robust resistance to cyclic degradation, offering a promising new approach for the development of sustainable technology. [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]

Multilayer ceramic capacitors (MLCCs) consist of multiple ceramic layers causing vibration owing to its piezoelectric characteristics. The vibrations are transmitted to the printed circuit board (PCB), causing acoustic noise. The mounting location and direction of the MLCC are crucial factors for reducing the acoustic noise. This paper presents a novel method for determining the optimal location and direction of MLCCs to reduce the acoustic noise. The excitation force of MLCC was simplified to calculate the vibroacoustic response of the PCB efficiently. Two design variables representing the MLCC location and direction were developed, and optimization problems were defined to minimize the acoustic noise. To validate the proposed method, the optimization problems were solved for an M.2 solid-state drive model under various scenarios. The results demonstrated that, on average, the overall sound power level was reduced by 4.59 dB for a single MLCC and 6.04 dB for multiple MLCCs. [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]

Rare earth (RE)-doped BaTiO3 materials are promising dielectric materials for base-metal electrode multilayer ceramic capacitors (BME-MLCCs). Thus, the fundamental understanding of their effect on dielectric properties and reliability is crucial for further improvement of its performance. Herein, according to Preisach model, the dielectric stability of Dy and Y-doped BaTiO3 MLCCs with different particle sizes was investigated in this study. First order reversal curve (FORC) analysis showed that the reversible and irreversible domain wall motion of Dy-doped samples was weaker than that of Y-doped samples. Results also showed that the higher "shell" proportion of "core-shell" structure in Dy-doping was beneficial for improving the dielectric stability and insulation resistance degradation. The findings provide a comprehensive understanding and illustrate the significant role of the "core-shell" volume ratio in the tetragonality and domain wall motion in RE-doped BaTiO3 materials, and consequently laying an important ground work to obtain high dielectric stability and reliability in BME-MLCCs. [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]

In this paper, a reduced‐switch‐count two‐phase interleaved LLC converter with precise current balancing is proposed by using switching‐control‐capacitor (SCC) technology. Compared with the conventional SCC‐LLC converter, the proposed two‐phase SCC‐LLC converter reduces the switch count with the SCC circuits, and achieves excellent current sharing under all the tolerance conditions between the two‐phase resonant elements. In the proposed converter, the SCC circuit is only used in the first phase. The design of the SCC circuit parameters is analyzed to reduce the voltage stress of the SCC circuit and to ensure that two‐phase currents are balancing with large tolerance of resonant elements. A 2.16‐kW GaN‐based two‐phase interleaved SCC‐LLC converter prototype is established for data center application, and the experimental results show that the 98.1% peak efficiency, the 97.6% full load efficiency, and higher than 96% efficiency at the wide range from 3‐A to 40‐A load current are achieved. The precise current sharing lower than 1% is achieved by using a cheap ceramic capacitor with high tolerance, which validates the performance of the converter. [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]

Capacitors exhibit exceptional power density, a vast operational temperature range, remarkable reliability, lightweight construction, and high efficiency, making them extensively utilized in the realm of energy storage. There exist two primary categories of energy storage capacitors: dielectric capacitors and supercapacitors. Dielectric capacitors encompass film capacitors, ceramic dielectric capacitors, and electrolytic capacitors, whereas supercapacitors can be further categorized into double-layer capacitors, pseudocapacitors, and hybrid capacitors. These capacitors exhibit diverse operational principles and performance characteristics, subsequently dictating their specific application scenarios. To make informed decisions in selecting capacitors for practical applications, a comprehensive knowledge of their structure and operational principles is imperative. Consequently, this review delved into the structure, working principles, and unique characteristics of the aforementioned capacitors, aiming to clarify the distinctions between dielectric capacitors, supercapacitors, and lithium-ion capacitors. [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]

Ceramic capacitors are receiving increasing interest because of their applications in pulsed-power devices. The perovskite oxide Bi0.5Na0.5TiO3 (BNT)-based ferroelectric ceramics are regarded as prospective lead-free candidate for dielectric capacitors because of the high polarization and outstanding relaxor behaviour. Herein, the relaxor ferroelectric (0.7−x)Bi0.5Na0.5TiO3–0.3SrTiO3–xCa0.7Sm0.2TiO3 ceramics synthesized through solid-state route and exhibited pseudocubic perovskite structure and strong relaxor behaviour. With increasing Ca0.7Sm0.2TiO3 content, the moderate permittivity and reduced grain size contributed to the monotonically increased electric breakdown strength. Among prepared samples, the x = 0.2 ceramic displayed slimmer polarization-electric field curves with a remarkable recoverable energy density (~6.8 J/cm3) and a satisfied efficiency (~82.2%) under external electric field of 450 kV/cm. Moreover, the x = 0.2 ceramic also exhibited a superb thermal reliability of energy storage properties (3.9–4.5 J/cm3 with variation of 13.3% in 25–160 °C) resulting from the diffuse phase transition. The above results make the x = 0.2 ceramics becoming promising candidates for pulsed-power devices. [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]

Purpose: This study aims to investigate the possible defects and their root causes in a soft-termination multilayered ceramic capacitor (MLCC) when subjected to a thermal reflow process. Design/methodology/approach: Specimens of the capacitor assembly were subjected to JEDEC level 1 preconditioning (85 °C/85%RH/168 h) with 5× reflow at 270°C peak temperature. Then, they were inspected using a 2 µm scanning electron microscope to investigate the evidence of defects. The reliability test was also numerically simulated and analyzed using the extended finite element method implemented in ABAQUS. Findings: Excellent agreements were observed between the SEM inspections and the simulation results. The findings showed evidence of discontinuities along the Cu and the Cu-epoxy layers and interfacial delamination crack at the Cu/Cu-epoxy interface. The possible root causes are thermal mismatch between the Cu and Cu-epoxy layers, moisture contamination and weak Cu/Cu-epoxy interface. The maximum crack length observed in the experimentally reflowed capacitor was measured as 75 µm, a 2.59% difference compared to the numerical prediction of 77.2 µm. Practical implications: This work's contribution is expected to reduce the additional manufacturing cost and lead time in investigating reliability issues in MLCCs. Originality/value: Despite the significant number of works on the reliability assessment of surface mount capacitors, work on crack growth in soft-termination MLCC is limited. Also, the combined experimental and numerical investigation of reflow-induced reliability issues in soft-termination MLCC is limited. These cited gaps are the novelties of this study. [ABSTRACT FROM AUTHOR]

A review of dielectric materials with high (exceeding 10,000) values of relative permittivity is presented. Most of the compositions of these materials are based on systems that include ferroelectric and non-ferroelectric components, as well as solid solutions based thereon. Various approaches to increasing the permittivity of materials are considered, including doping, sintering atmosphere, grinding time, sintering temperature, and grain size. The effect of dopants and the synthesis method on the characteristics of capacitor ceramics that can be used in the low-frequency and high-frequency range are compared. [ABSTRACT FROM AUTHOR]

Capacitors are crucial components in power electronic converters, responsible for harmonic elimination, energy buffering, and voltage stabilization. However, they are also the most susceptible to damage due to their operational environment. Accurate temperature estimation of capacitors is essential for monitoring their condition and ensuring the reliability of the converter system. This paper presents a novel method for estimating the core temperature of capacitors using a long short-term memory (LSTM) algorithm. The approach incorporates a continued training mechanism to adapt to variable load conditions in converters. Experimental results demonstrate the proposed method's high accuracy and robustness, making it suitable for real-time capacitor temperature monitoring in practical applications. [ABSTRACT FROM AUTHOR]