Ceramic Capacitors Research Articles

Enhancing the thermal stability of the dielectric property by tilting the NbO6 octahedra in (Na1-zKz)NbO3-SrTiO3 ceramics

(1-x) (Na0.2K0.8)NbO3-xSrTiO3 [(1-x) (N0.2K0.8)N-xST] ceramics with a homogeneous perovskite structure were well-sintered in the range of 1080–1160 °C. The 0.9(N0.2K0.8)N-0.1ST ceramic was found to have a temperature-stable dielectric constant (εr) that complies with the X9R multilayer ceramic capacitor (MLCC) requirement. The temperature stability of the εr value was also investigated for the 0.9(N1-zKz)N-0.1ST ceramics (0.0 ≤ z ≤ 1.0). The results indicated that as z (or K+ ions) increased, the Curie temperature (TC) decreased, and its peak broadened. The broadening of the TC peak was attributed to the development of the relaxor property owing to the tilting of the NbO6 octahedra. The 0.9(N1-zKz)N-0.1ST ceramics (0.7 ≤ z ≤ 1.0) exhibited a temperature-independent εr value, thus fulfilling the X9R MLCC requirement because of the broad TC peak. The MLCC fabricated from 0.9(N0.2K0.8)N-0.1ST thick films complied with the X9R MLCC requirement with excellent capacitance stability under the supplied electric field. Hence, 0.9(N1-zKz)N-0.1ST ceramics (0.7 ≤ z ≤ 1.0) are good candidates for X9R MLCCs.

Quantitative evaluation of the degradation acceleration of insulation at local area in multilayer ceramic capacitors

The degradation acceleration based on dielectric thickness was evaluated by analyzing the local insulation degraded area in prototype Ni-BaTiO3 multilayer ceramic capacitors. Locally thinned dielectric layers, resulting from nickel internal electrode bulges, were associated with shorter lifetimes than the mean time to failure observed in highly accelerated life test. A strong correlation was observed between the minimum thickness of the dielectric layer at the degraded area and the lifetime. The electric field acceleration coefficient was derived from the correlation between the electric field strength, calculated from the dielectric thickness at the degraded area, and the lifetime. The impact of dielectric thinning on degradation acceleration was quantified by analyzing these local degraded areas. The factors influencing degradation acceleration were also discussed based on these findings.

Equivalent Source Investigation for PCB Vibration Excited by a Multilayer Ceramic Capacitor

Equivalent Source Investigation for PCB Vibration Excited by a Multilayer Ceramic Capacitor

Reestablishment of dielectric and nonlinear properties for Bi3+ doped CaCu3Ti4O12 ceramics prepared by reduction-reoxidation method

Multilayer ceramics with base metal internal electrodes should be prepared through reduction sintering to avoid the oxidation of the electrodes, followed by a reoxidation process. In this study, Ca1-xBixCu3Ti4-x/4O12 + 0.03 BN ceramics were fabricated using the reduction-reoxidation method and the reestablishment of dielectric and nonlinear characteristics was investigated. It was observed that the dielectric and nonlinear properties depended crucially on the grain size and the second phases at the grain boundaries. The reoxidation behavior was remarkably improved when grain growth was suppressed and second phases were introduced. Optimal electrical properties were obtained for samples with x = 0.1 sintered at 1050 °C and reoxidized at 800 °C. The dielectric loss decreased to a value of about 0.14, while the permittivity remained a relatively large value of about 9.9 × 103 at 103 Hz. Additionally, the nonlinear coefficient and breakdown field were improved to a value of 2.2 and 981.8 V/cm, respectively. This study illustrates an efficient approach to enhance the reestablished dielectric and nonlinear properties for Bi3+ doped CaCu3Ti4O12-based ceramics fabricated through the reduction-reoxidation method.

Acoustic-noise reduction in printed circuit boards based on location and direction of multilayer ceramic capacitors

Acoustic-noise reduction in printed circuit boards based on location and direction of multilayer ceramic capacitors

High-temperature BaTiO 3-based ceramic capacitors by entropy engineering design

High-temperature BaTiO ₃-based ceramic capacitors by entropy engineering design

Polymorphic Localized Heterostructure Design for High-Performance Amorphous/Nanocrystalline Composite Film.

Analogous to linear dielectric, amorphous perovskite dielectrics characterized of high breakdown strength and low remanent polarization possess in-depth application in the sea, land, and air fields. Amorphous engineering is a common approach to balance the inverse relationship between polarization and breakdown strength in dielectric ceramic capacitor, however, the low polarization is the major barrier limiting the improvement of energy storage density. To address this concern, the polymorphic localized heterostructure confirmed by high-resolution transmission electron microscope (HR-TEM) and HADDF images is constructed in BaTiO3-Bi(Ni0.5Zr0.5)O3 amorphous/nanocrystalline composite film with SiO2 addition (BT-BNZ-xS, x = 3, 5, 7, 10 mol%). The stability of nanocrystalline region achieved by Si-rich transition region and the enhancive ultra-short-range ordering in the amorphous region synergistically result in large breakdown strength and nonhysteretic polarized response. This polymorphic localized heterostructure optimizes the thermal stability in a wide temperature range and contributes ultrahigh energy storage density of 149.9 J cm-3 with markedly enhanced efficiency of 79.0%. This study provides a universal strategy to design the polarization behavior in other amorphous perovskite-based dielectrics.

Outstanding comprehensive energy storage performances in multiscale synergistic regulation-engineered (Bi0.5Na0.5)TiO3-based multilayer ceramics

Environmentally friendly dielectric ceramics with superior energy storage performances (ESP) are strongly demanded in pulsed power capacitor applications. Unfortunately, it is challenging to achieve simultaneously large recoverable energy density (Wrec), high Wrec/E (E as electric field) and broad operating temperature range in those ceramics. Herein we propose a multiscale synergistic regulation strategy to enhance comprehensive ESP of (Bi0.5Na0.5)TiO3 (BNT)-based ceramics. We introduce Ca(Zr0.8Ti0.2)O3 (CZT) into the BNT to increase atomic chaos and lattice distortion, which enhances relaxor behavior and lowers domain-switching barriers, thus effectively reducing remanent polarization. Besides, both suppressed oxygen vacancy and refined submicron grains improve extrinsic resistivity, which works synergistically with the enlarged intrinsic bandgap and multilayer structure design, producing substantially enhanced breakdown strength. Encouragingly, a very large Wrec of 13.4 J/cm3, an ultrahigh Wrec/E of 160 J/(kV∙m2), and a high efficiency η of 90.2 % are simultaneously achieved in the novel (Bi0.5Na0.5)TiO3-Ca(Zr0.8Ti0.2)O3 (BNT-CZT) multilayer ceramics, together with outstanding energy storage stability over a broad working temperature range (20–180 °C). The comprehensive ESP of our multilayer ceramics are superior to most of previously reported lead-free ones. This work provides a feasible pathway for substantially improving comprehensive ESP of lead-free ceramics, and also highlights advanced energy storage potential of the BNT-CZT for high-performance pulsed power applications.

Review of Energy Storage Capacitor Technology

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.

Utilizing Domain Engineering to Achieve High-Polarization Relaxor Ferroelectrics for Low-Consumption Ceramic Capacitors.

This study focuses on incorporating NaNbO3 (NN) into the Ba0.85Ca0.15Zr0.9Ti0.1O3 (BCZT) lattice to form (1 - x)BCZT-xNN ceramics. Although antiferroelectricity was not observed, an observed domain-movement-diminishment behavior with increasing NN dopant induced the formation of high polarization walls (HPWs) between adjacent C-phases. The 0.90BCZT-0.10NN composition exhibited superior polarization compared to most BCZT-based ferroelectrics, as validated by mathematical derivation. Integration of these findings revealed a Wrec of 3.86 J/cm3 at 360 kV/cm, with a high Wrec/Eb ratio defining energy consumption efficiency in dielectric capacitors. This work introduces a novel approach to fabricating low-consumption dielectric capacitors. Additionally, a significantly high Wrec of 5.36 J/cm3 was achieved with an NN dopant concentration of 0.30.

Achieving high adhesion and low‐temperature sintering for multilayer ceramic capacitors by tunning the structure of SrO‐ZnO‐B2O3‐SiO2 glass

AbstractMultilayer 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.

CaTiO3 nanoparticles as functional additives for the BaTiO3-based X8R type dielectric ceramics

This research investigates the potential of Calcium titanate (CaTiO3 or CT) nanoparticles as functional additives to enhance the dielectric properties of Barium titanate (BaTiO3 or BT)-based ceramic dielectrics. To address the need for high-temperature stability in MLCC (multilayer ceramic capacitor) applications, especially within the automotive and aerospace sectors, we have explored BT-based complex perovskite solid solutions comprising various cation substitutions, including Ca2+ and Yb3+, into barium titanate (BT) as a method to suppress the dielectric property anomaly near the Curie temperature effectively. The focus is on the impact of the application of CT nanoparticles as additive materials on phase formation, microstructure development, and dielectric behavior of the resulting ceramics to align with the Extended 'Temperature Coefficient of Capacitance (TCC)' criteria defined by the EIA X8R specification. When the hydrothermally synthesized CT nanopowder was applied in the Ca-doped BT ceramics fabrications as source material of the Ca dopants, it was beneficial to achieve both temperature stability and high dielectric constant. The CT nanoparticles are believed to play multiple roles during the solid-state reaction with BT and rare earth dopant (Yb). Since the Yb3+ ions can be more easily dissolved into the CT lattice than BT with their amphoteric character, the CT nanoparticles in the BT-CT-Yb2O3 mixture can act as an intermediary, dissolving the Yb3+ first in its A- or B-site before the final solid-solution formation with the BT. The sequential substitutions of the Yb3+ and Ca2+ into BT via CT nanoparticles could affect the site occupancy of Ca2+ in the BT lattice, which is very important in determining the dielectric properties of the Ca-doped BT processed in reducing atmospheres. Through a comprehensive experimental approach, including phase composition analysis via X-ray diffraction (XRD) and microstructural examination using Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM), this work reveals the significance of synthetic methodology and dopant incorporation strategy on achieving a desired core-shell microstructure and improved dielectric performance. This research underscores the efficacy of CT nanoparticles as a promising route towards the development of BT-based dielectric ceramics with superior temperature stability, offering valuable insights for the advancement of MLCC technology to cater to high-temperature applications.

Multilayer ceramic capacitor induced audible noise simulation

Multilayer ceramic capacitors (MLCCs) are one of the most widely used capacitors. Their small size, high capacitance, high reliability and low cost make them ideal for miniaturized electronic devices. However, their piezoelectric effect may cause the deformation of the capacitor associated with the applied voltage. Even worse, the deformation may cause the PCB vibration and potential noise radiation, which can be a problem for devices designed to be quiet, such as cellphones, earbuds, laptops, etc. This paper introduces how MLCCs can cause PCB vibration and noise radiation problems by simulating a single MLCC with piezoelectric effect. And then, a methodology is proposed on how to quantify the MLCC as vibration load source. Moreover, a simplified process is illustrated to simulate the MLCC induced noise radiated from circuit boards. Finally, a couple applications are demonstrated by using the developed process.

Fully Printed Multilayer Ceramic Capacitors Based on High-k Perovskite Nanosheets.

Printing technology enables the integration of chemically exfoliated perovskite nanosheets into high-performance microcapacitors. Theoretically, the capacitance value can be further enhanced by designing and constructing multilayer structures without increasing the device size. Yet, issues such as interlayer penetration in multilayer heterojunctions constructed using inkjet printing technology further limit the realization of this potential. Herein, a series of multilayer configurations, including Ag/(Ca2NaNb4O13/Ag)n and graphene/(Ca2NaNb4O13/graphene)n (n = 1-3), are successfully inkjet-printed onto diverse rigid and flexible substrates through optimized ink formulations, inkjet printing parameters, thermal treatment conditions, and rational multilayer structural design using high-k perovskite nanosheets, graphene nanosheets and silver. The dielectric performance is optimized by fine-tuning the number of dielectric layers and modifying the electrode/dielectric interface. As a result, the graphene/(Ca2NaNb4O13/graphene)3 multilayer ceramic capacitors exhibit a remarkable capacitance density of 346±12nFcm-2 and a high dielectric constant of 193±18. Additionally, these devices demonstrate moderate insulation properties, flexibility, thermal stability, and chemical sensitivity. This work shed light on the potential of multilayer structural design in additive manufacturing of high-performance 2D material-based ceramic capacitors.

Efficiently high energy storage density in Ba2+ ion modified K0·5Na0·5NbO3 (KNN) ferroelectric ceramics for super capacitors

In the present work, Perovskites BaxK0.5-xNa0.5NbO3 (x = 0.00, 0.05, 0.10, 0.15, 0.20) were synthesized via solid-state synthesis technique. XRD analysis confirmed the successful phase formation of the synthesized perovskites. Further, Rietveld refinement revealed the presence of coexisting orthorhombic and tetragonal phases. High-resolution transmission electron microscopy (HRTEM) was employed to explore the lattice fringes and SAED patterns at nano scale level of prepared samples. The morphology was investigated using a field emission scanning electron microscope (FESEM). Dielectric measurements indicated that both the dielectric constant (ε′) and loss tangent (tan δ) exhibited significant dispersion at low frequencies and high temperatures. Notably, the Ba-doped perovskite samples demonstrated enhanced dielectric properties compared to the undoped KNN sample, with Ba0·1K0·4Na0·5NbO3 (x = 0.10) showing optimal dielectric performance, characterized by a dielectric constant (ɛ՛⁓4000) and a tanẟ ⁓7.23 at 100 Hz frequency and room temperature.AC conductivity is observed to increase with increasing both frequency and temperature. DC conductivity exhibited positive temperature coefficient indicating the semiconductor-like behavior of the prepared samples. The ferroelectric behavior was confirmed through P-E hysteresis curves and Ba0·1K0·4Na0·5NbO3 sample revealed the highest energy storage density among all prepared samples making it a suitable candidate for energy storage applications.

Significantly enhanced reliability in defect-engineered BaTi1-xMgxO3 ceramics

BaTiO3-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 BaTiO3 (Mg: 0.2, 0.5, 1.0, 1.5, 2.0, and 5.0 mol%) ceramics with Al2O3 and SiO2 as sintering additives. With an increase in Mg concentration, the insulation resistance of the BaTi1-xMgxO3 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 BaTiO3 ceramics. It identifies a pathway to achieve high reliability in BaTiO3-based MLCC.

High energy-storage properties of Sr0.7Bi0.2-xLaxTiO3 lead-free relaxor ferroelectric ceramics for pulsed power capacitors

Ceramic capacitors are very promising to be commercialize with ease for high pulse power technology owing to their fast charging/discharging rate, high bending strength and as well as their high energy density. Small, fine, and compacted grains in conjunction with slim P-E loops, and high breakdown electric field strength (Eb) play crucial role in the improvement of recoverable energy storage density. In this work, the microstructure and electrical properties of La2O3 modified Sr0.7Bi0.2-xLaxTiO3 ceramics (SBLTO, x = 0, 0.01, 0.02, and 0.05, and short for SBTO, SBLTO-0.01, SBLTO-0.02, and SBLTO-0.05, respectively) were investigated in details. Furthermore, introducing La2O3 into SBTO ceramics not only refined grains and increased insulation resistance, but also resulted in significantly better energy-storage characteristics, as compared with the pure SBTO ceramics. Recoverable energy-storage density (Wrec) was obtained up to 5.8 J/cm3 in SBLTO-0.01 lead-free ceramic, which is better than that of other reported SBTO-based ceramics. Moreover, the Wrec of the SBLTO-0.01 ceramic also presents good frequency (2–500 Hz) and thermal (25–120 °C) stabilities under an electric field strength of 150 kV/cm. Furthermore, the charge-discharge results demonstrated a high power density∼92 MW/cm3 and a short discharging speed time∼39 ns. As a result, our work offers SBTO-based ceramics with a feasible method for enhancing the energy-storage characteristic.

Multifunctional Design for Arbitrary Multiband Radome Wall Accelerated by Artificial Intelligence

A hypersonic airborne radome must possess multiband electromagnetic transparency, high specific strength, and thermomechanical resistance to ensure proper antenna operation. However, achieving these multifunctional properties in radome wall design is challenging due to conflicting material requirements. Moreover, existing design methods for arbitrary multiband and broadband hypersonic radomes are insufficient. This paper presents an efficient method that integrates artificial intelligence and an evolutionary algorithm to enable the multidisciplinary synchronous design of the radome wall. The designed radome walls using multilayered porous silicon-nitride ceramics achieve power transmission efficiency exceeding 90% in a broadband of 30 GHz or arbitrary multiple bands with bandwidths of 5 GHz, covering the centimeter-to-millimeter wave range. Moreover, the designed laminate also meets requirements of flexural strength surpassing 60 MPa and a maximum thermal stress–strength ratio below 1. Notably, the utilization of artificial intelligence accelerates the design process by at least 1093 times compared to conventional methods.

Designing a Cost‐Effective and Sustainable Process for the Efficient Production of Planar Anode‐Supported Solid Oxide Fuel Cells

A sustainable process is designed to produce anode‐supported solid oxide fuel cells (SOFCs). Environmentally friendly solvents and additives are selected to prepare sequentially cast slurries to obtain a flexible multilayer tape whose cohesion is ensured by a 3D network of binder. This tape includes the components of the oxide precursor of the half cell with the functional and structural part of the anode. The optimization of debinding and sintering processes allows converting green tape into sintered multilayer ceramic using a single heat treatment. The use of optimized loads maintains planarity of samples with adjusted shape (circular to square) and size (from 0.8 up to 8 cm2) of anodic half cell. The cell's oxide precursor is supplemented by screen printing the cathode and converted to anode‐support SOFC when the cell is first used. The whole process maintains mechanical integrity, microstructure of structured components, and insures interfaces enabling charge transfer high enough to achieve standard performances such as power of 411 mW cm−2. The selection of cheap and harmless solvents and additives and the optimization of heat treatment lead to an ecocompatible low‐cost process for manufacturing SOFCs, easily transferable to the industrial scale and suitable for the manufacture of all systems based on ceramic multilayers.

High energy storage performance under low electric fields and remarkable dielectric temperature stability in (Na0.5Bi0.5)TiO3-based lead-free ceramics

Lead-free ceramic capacitors with superior energy storage properties and dielectric temperature stability are urgent needs for pulsed power devices. However, the risk of high voltage suppresses the improvement of comprehensive performance. Thus, a novel (1-x)(0.55Na0.5Bi0.5TiO3-0.45Ba0.85Ca0.15Zr0.1Ti0.9O3)-xBi(Mg2/3Ta1/3)O3 (NBBCZT-xBMT) ceramics were successfully synthesized to address the above concerns. The addition of BMT is beneficial to maintaining high polarization strength, improving the breakdown strength and optimizing relaxor behavior. As a result, the optimum component exhibits excellent energy storage capability (Wrec = 3.05 J/cm3, η = 94.3 %) at 190 kV/cm and dielectric temperature stability (TCC ≤ ±10 % from 33 to 348 °C, tanδ ≤ 0.01 from 50 to 389 °C). Moreover, the corresponding sample maintains a variation of Wrec less than 6.7 % and η less than 1.6 % at 20–140 °C and 1–100 Hz. These results provide a novel candidate for high-performance ceramic capacitors under low electric fields.