Ceramic Capacitors Research Articles

Improving energy storage performance of BLLMT ceramic by doping BZT combining with defect engineering and film scraping process

The (1-x)(Ba0.94Li0.02La0.04)(Mg0.04Ti0.96)O3-xBi(Zn1/2Ti1/2)O3 ((1-x)BLLMT-xBZT, x = 0.02, 0.04, 0.06, 0.08, 0.10, 0.12) ceramic thick films were prepared by traditional solid-state sintering method combined with film scraping process. Li+ and La3+ ions doping at A-site, and Mg2+ and Zn2+ ions doping at B-site of the perovskite structure, and adding BZT component enhance charge compensation, enlarge polarization difference, increase breakdown strength, and enhance relaxation degree, leading to the improved pulse charging and discharging energy storage performance of the BaTiO3-based ceramic films. The 0.92BLLMT-0.08BZT ceramic film has high discharge energy density of 4.61 J/cm3, high pulse power density PD = 224.14 MW/cm3, high current density CD = 896.58 A/cm2, high discharge speed of 234 ns, and high pulse discharge density Wd = 4.61 J/cm3 under 500 kV/cm combined with high breakdown strength of 500 kV/cm, relating to charge compensation, multiple ferroelectric phases coexistence, and formation of polar nanoregions. The strategy by equivalent and heterovalent ions doping at A-site and B-site of the perovskite structure and introducing Bi-based component combined with film scraping process strengthens charge compensation, enhances relaxation characteristic, and reduces grain size, providing an efficient route to develop prospect BT-based dielectric ceramic capacitors for potential application in high-power pulse energy storage such as 0.92BLLMT-0.08BZT.

Impact of synthesis route on the microstructure and energy-storage properties of (Bi1/2K1/2)TiO3–SrTiO3 relaxor ferroelectric ceramics: Solid-state and hydrothermal approaches

Bismuth potassium titanate (Bi1/2K1/2)TiO3-based relaxor ferroelectrics are promising materials for high-energy-density ceramic capacitors. Herein, we compare the microstructure and energy-storage properties of (Bi1/2K1/2)0.5Sr0.5TiO3 (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.

Analysis, Design, and Experimental Assessment of a High Power Density Ceramic DC-Link Capacitor for a 800 V 550 kVA Electric Vehicle Drive Inverter

Analysis, Design, and Experimental Assessment of a High Power Density Ceramic DC-Link Capacitor for a 800 V 550 kVA Electric Vehicle Drive Inverter

Prototyping Na0.5Bi0.5TiO3-based multilayer ceramic capacitors for high-temperature and power electronics

Prototyping Na0.5Bi0.5TiO3-based multilayer ceramic capacitors for high-temperature and power electronics

Loss Characterization and Modeling of Class II Multilayer Ceramic Capacitors: A Synergistic Material-Microstructure-Device Approach

Loss Characterization and Modeling of Class II Multilayer Ceramic Capacitors: A Synergistic Material-Microstructure-Device Approach

Enhanced dielectric properties and improved thermal stability in TiO2-based ceramics by Cu and Nb co-doping

TiO2-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 TiO2 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 (Cu1/3Nb2/3)0.005Ti0.995O2 and (Cu1/3Nb2/3)0.01Ti0.99O2 exhibit large dielectric permittivity (εr) 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 εr keeps stable of ±7.5% at 1 kHz from −200 to 200 °C for (Cu1/3Nb2/3)0.005Ti0.995O2 and from 10 to 200 °C for (Cu1/3Nb2/3)0.01Ti0.99O2 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.

Boosting energy storage performance in negative temperature coefficient linear-like dielectrics via composite modulation in the superparaelectric state

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 BaTiO3-BaZrO3-CaTiO3 (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 (Eb). Benefiting from these features, EIA class I-R3L code NTCC together with a high Wrec (∼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.

Sinterability of sodium bismuth titanate-based electroceramics at low temperatures

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 Na0.5Bi0.5TiO3 (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 (Li2O, Na2O, Bi2O3, B2O3, ZnO, and V2O5) to lower the sintering temperature of Na0.5Bi0.5TiO3-BaTiO3-CaZrO3-BiAlO3 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.

High recoverable energy density of Na0.5Bi0.5TiO3-based ceramics by multi-scale insulation regulation and relaxor optimization strategy

Dielectric ceramic capacitors (DCCs) are highly desired for advanced electronic and electrical power systems owing to their ultrahigh power densities and fast charge-discharge speed. However, the low recoverable energy density (Wrec) of dielectric ceramic resulting from the low Weibull breakdown strength (Eb) has been a long-standing challenge. Here, we fabricated 0.8Na0.5Bi0.5TiO3–0.2Sm1/3Sr1/2(Mg1/3Nb2/3)O3 (0.8NBT–0.2SSMN) relaxor ferroelectric (RFE) ceramics display a greatly improved Eb of 480 kV/cm and largely enhanced Wrec of 7.3 J/cm3, far outperforming pure NBT ceramic. We demonstrate that the proposed multi-scale insulation regulation strategy via introducing SSMN with optimal content can effectively reduce grain sizes, increase the bandgap, and create a highly insulating second phase, leading to a high Eb. Additionally, the introduction of Sm3+ and Mg2+–Nb5+ dopants on the A/B-sites of the Na0.5Bi0.5TiO3 lattice created disruptions in the long-range-ordered ferroelectric domains, leading to excellent RFE property. The high Eb and excellent RFE property led to the substantial improvement of Wrec. Else, an exceptional thermal stability of Wrec and efficiency (η) are obtained at 25–200 °C (Wrec ∼ (1.77 ± 0.08) J/cm3, η ∼ 82.9% ± 4.3%). This work offers a route for designing high energy storage performance relaxor ferroelectric ceramics for high-voltage dielectric ceramic capacitors.

Enhancement of Energy-Storage Properties and Temperature Stability in Complex Perovskite (1−x)NaNbO3−xBi(Li1/3Sn2/3)O3 Lead-Free Ceramics

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

Effect of ferrite phase addition on Pb-Free multiferroic composite material for energy storage applications

Bulk composite ceramics exhibit promising potential as energy storage materials due to their strong ferroelectric characteristics. To lessen the use harmful Pb based material, multiferroic composite combining ferrite and perovskite ceramics with piezoelectric and ferroelectric traits, have gained prominence for high-efficiency energy systems such as ceramic capacitor. This study focuses on a dual-phase multiferroic ceramic composite, following the formula (1-x) Ba0.77Ca0.23TiO3 + xNi0.6Zn0.25La0.15Fe2O4 (x = 0.0, 0.1, 0.2, and 0.3), prepared via a solid-state reaction process. XRD analysis confirms the presence of cubic perovskite (BaTiO3) and cubic spinel ferrite (NZLFO) phases. SEM images depict uniform microstructures with sporadic pore formations, which decreased in grain size with ferrite addition. The P-E loops reveal relaxor ferroelectric behavior with near-zero remnant polarization (Pr), indicating its suitability as an energy storage medium. The highest energy density efficiency, approximately 54 %, was achieved at x = 0.1. The addition of more than 10 % ferrite significantly affects both the microstructure and energy storage properties.

Antiferroelectric ceramic capacitors with high energy-storage densities and reduced sintering temperature

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 (EFE-AFE) using elemental dopants. In this case, Cd2+ was selected as the dopant at A-site in the Pb0.97La0.02Zr0.50Sn0.45Ti0.05O3 ceramics to tailor this EFE-AFE value due to the ionic difference enhanced antiferroelectricity. Surprisingly, the doped ceramics increased EFE-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.

Microstructure, physical and mechanical properties of dental polychromic multilayer zirconia of uniform composition.

The present study aimed to compare the microstructure, physical, and mechanical properties of three commercially available dental polychromatic multilayer zirconia materials of uniform composition: Dima Mill Zirconia ML, VITA YZ/ST Multicolor, and VITA YZ/XT Multicolor (with 3, 4, and 5mol% Y2 O3 , respectively); thus, the influence of Y2 O3 content on the above properties of the produced materials was experimentally studied. Homogeneous zirconia ceramics with a dense micro- and nanostructure, without pores or defects, were produced after milling the blocks and sintering, which resulted in yttrium-stabilized tetragonal and cubic zirconia. Statistical analysis of the results of measurable magnitudes was performed by the one-way ANOVA test. The increase of Y2 O3 content (from 3 to 5mol%) favored larger grain and crystallite sizes and a decrease of the values of the mechanical properties; yet, the differences were statistically insignificant. Clinically, these differences are expected to have no impact on their function in the oral cavity, both in terms of their fracture propensity and the damage that can be caused to the opposing teeth. Accordingly, the experimental results qualify the polychromic multilayer zirconia ceramics of uniform composition fabricated by milling technology for use in dental restorations.

Lower-temperature sintered high energy density fine-grained sodium bismuth titanate - strontium bismuth titanate ceramics multilayer capacitors

The breakdown field strongly determines the energy density of energy-storage ceramic capacitors. In this work, a compound sintering aid of CuO and SiO2 was preferably selected to explore the effect on sintering behavior and energy storage of sodium bismuth titanate - strontium bismuth titanate (NBT-SBT) relaxor ferroelectrics. The optimum sintering temperature promotes a dense microstructure and fined-grain size in NBT-SBT, which contributes to an increase in breakdown strength. Meanwhile, the appropriate CuO/SiO2 ratio retains the advantages of the high polarization value of NBT-SBT. Specifically, when sintered at 1040 °C with 0.2 wt% SiO2 and 0.8 wt% CuO composite sintering aids, the NBT-SBT bulk ceramics achieved an energy storage density of 4.09 J/cm3 under a high electric field of 270 kV/cm. Owing to the lower sintering temperature, the NBT-SBT achieved co-firing with 30/70 Ag/Pd electrodes. Finally, multilayer ceramic capacitors with a recoverable energy density of 8.43 J/cm3 have been successfully fabricated.

Erratum: “Insulation degradation behavior of multilayer ceramic capacitors clarified by Kelvin probe force microscopy under ultra-high vacuum” [J. Appl. Phys. 113, 064103 (2013)

Erratum: “Insulation degradation behavior of multilayer ceramic capacitors clarified by Kelvin probe force microscopy under ultra-high vacuum” [J. Appl. Phys. 113, 064103 (2013)

Boosting capacitive performance of lead-free relaxor ferroelectrics by introducing a linear dielectric

As an important core component used in high-power pulse electronic systems, dielectric ceramic capacitors have gained great interest because of their ultrahigh powder density (PD) and fast discharge speed (t0.9). However, inferior energy storage performance (ESP) greatly limits the development of energy storage devices with the requirement of miniaturization and integration. Herein, we propose a feasible approach to introduce linear dielectric CaTiO3 (CT) into (Bi0.5Na0.5)TiO3 (BNT) for the design of engineered relaxor ferroelectrics to tune ESP at the grain, domain, and macroscopic scales. The results demonstrate that introducing CT generates enhanced relaxor behavior with highly dynamic polar nanoregions, refines grain size, and suppresses dielectric loss, synergistically yielding increased breakdown strength, negligible remnant polarization, and a nearly linear polarization hysteresis loop. Consequently, superior ESP is achieved in BNT-0.3CT relaxor ferroelectric ceramics with a large energy density (∼5.65 J/cm3) and a high efficiency (∼88.1 %). Based on CT-induced merits, the excellent temperature/frequency/cycling stabilities and remarkable charge-discharge properties featuring a high PD of 200.4 MW/cm3, high discharge energy density of 2.27 J/cm3 and ultrashort t0.9 of 58 ns of the designed ceramics broaden the actual application prospects. This work demonstrates that introducing linear dielectric CT holds great promise for developing high-performance energy storage dielectrics.

Improved Energy Storage Density and Efficiency of Nd and Mn Co-Doped Ba0.7Sr0.3TiO3 Ceramic Capacitors Via Defect Dipole Engineering.

In this paper, we investigate the structural, microstructural, dielectric, and energy storage properties of Nd and Mn co-doped Ba0.7Sr0.3TiO3 [(Ba0.7Sr0.3)1-xNdxTi1-yMnyO3 (BSNTM) ceramics (x = 0, 0.005, and y = 0, 0.0025, 0.005, and 0.01)] via a defect dipole engineering method. The complex defect dipoles (MnTi"-VO∙∙)∙ and (MnTi"-VO∙∙) between acceptor ions and oxygen vacancies capture electrons, enhancing the breakdown electric field and energy storage performances. XRD, Raman, spectroscopy, XPS, and microscopic investigations of BSNTM ceramics revealed the formation of a tetragonal phase, oxygen vacancies, and a reduction in grain size with Mn dopant. The BSNTM ceramics with x = 0.005 and y = 0 exhibit a relative dielectric constant of 2058 and a loss tangent of 0.026 at 1 kHz. These values gradually decreased to 1876 and 0.019 for x = 0.005 and y = 0.01 due to the Mn2+ ions at the Ti4+- site, which facilitates the formation of oxygen vacancies, and prevents a decrease in Ti4+. In addition, the defect dipoles act as a driving force for depolarization to tailor the domain formation energy and domain wall energy, which provides a high difference between the maximum polarization of Pmax and remnant polarization of Pr (ΔP = 10.39 µC/cm2). Moreover, the complex defect dipoles with optimum oxygen vacancies in BSNTM ceramics can provide not only a high ΔP but also reduce grain size, which together improve the breakdown strength from 60.4 to 110.6 kV/cm, giving rise to a high energy storage density of 0.41 J/cm3 and high efficiency of 84.6% for x = 0.005 and y = 0.01. These findings demonstrate that defect dipole engineering is an effective method to enhance the energy storage performance of dielectrics for capacitor applications.

An update on high temperature tantalum capacitor technology

Developments and improvements in the materials, design and manufacturing of tantalum bulk capacitors have resulted in new case sizes, improved ESR, higher operating voltages and temperatures. This work discusses the basic design and manufacture of hermetic tantalum and wet tantalum capacitors and the resulting high temperature performance offered by each technology. Specifically, hermetic sealed tantalum capacitors offer a novel set of design options for the high temperature designer. This technology, exhibits superior stability when exposed to high temperatures, high humidity, and ambient atmosphere. The device is impervious to the typical capacitance drop common to high temperature capacitor operation. Thus they enable potentially significant size reductions, lower component counts, and reliability improvements in extremely high temperature applications, such as downhole oil drilling. Both electrical and physical comparisons are made between the characteristics of bulk stacked ceramic capacitors, hermetic tantalum and wet tantalum devices across an operating range of -55°C to +230°C. Lifespan and recommended de-ratings are presented.

A way for densification of lead-free BaTiO3-based/ZrO2 laminates for energy harvesting applications prepared by electrophoretic deposition

In this paper, the concept of multi-layer ceramics based on a combination of piezoelectric layers BaTiO3 (BT) or (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) alternated with mechanically durable ZrO2 (Z) layers is investigated. Both BT/Z and BCZT/Z laminates were successfully electrophoretically deposited (EPD) due to knowledge of the deposition kinetics of individual materials and their green densities allowing precise layer thickness control. The EPD was followed by conventional sintering (CS) or spark plasma sintering (SPS). The CS resulted in the development of cracks, pores, and significant chemical reactions at the layers interfaces in both types of laminates. Laminates sintered by SPS were crack free with suppressed or none chemical reactions at the interfaces. The mechanical properties development across layers was monitored using nanoindentation. This approach identified interlayer porosity evolution and estimated the significance of the reaction zone at the interface.

Novel high-entropy relaxors with ultrahigh energy-storage efficiency and density

One of the major problems in ceramic capacitors is that their limited energy storage density (Wrec) and efficiency restrict the development in cutting-edge energy storage applications. In this paper, the non-equimolar ratio high-entropy ceramics are designed using the “entropy” strategy based on the traditional ferroelectric BaTiO3. Ultimately, the superparaelectric region of BaTiO3 is extended successfully, forming the local polymorphic distortion structure and realizing the transformation of ferroelectrics-relaxor ferroelectrics. Here, the outstanding Wrec of 7.3 J/cm3, the excellent ξ of 214.71 J/kV·m2, and the highest energy storage efficiency (η = 94.3 %) in high-entropy ceramics are obtained under moderate electric fields, indicating a breakthrough progress in energy storage applications of high-entropy relaxor ferroelectrics. Additionally, our work compared performance across multiple dimensions using measurement parameters, giving readers a more comprehensive reference.