Dielectric Capacitor Applications Research Articles

Preparation and investigation of structural, optical, and dielectric properties of PVA/PVP blend films boosted by MWCNTs/AuNPs for dielectric capacitor applications

With the rising global energy demands, there is a pressing need for the invention of efficient and reliable energy storage systems. This research centers on the creation and analysis of flexible dielectric capacitors composed of polymer nanocomposites (PNCs), incorporating a blend of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) as the base polymer, with multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) serving as nanofillers. The AuNPs were produced through an environmentally friendly synthesis method. Films made from PVA/PVP blended with MWCNTs and AuNPs were fabricated using the casting approach. Various characterization methods, including TEM, XRD, FTIR, and UV–Vis spectroscopy, were utilized to evaluate the samples. A detailed analysis of their electrical/dielectric characteristics was conducted. XRD analysis revealed a significant decrease in crystallinity from 55% for the pure PVA/PVP blend to 37% for the 1.6 wt% nanofiller composite, indicating increased amorphous content, which facilitates better ion mobility. FTIR confirmed strong interactions between the polymer matrix and nanofillers, with intensified vibrational peaks pointing to enhanced molecular dynamics. UV–Vis spectroscopy demonstrated a red shift in the absorption edge, and Tauc plot analysis showed a reduction in the indirect/direct optical band gap from 4.84 eV/5.68 eV for the pure blend to 4.26/5.35 eV for the nanocomposite with 1.6 wt% nanofillers. The addition of nanofillers resulted in improvements in their dielectric features, which exhibited a significant performance improvement, with the dielectric constant (ε′) reaching approximately 1100 at low frequency for the 1.6 wt% nanofiller sample, compared to 9 for the pure blend. Additionally, the dielectric loss (ε'') and tangent loss (tan δ) were reduced, with tan δ showing a decrease from 15 for the pure blend to 2 for the 1.6 wt% nanofiller composite at low frequency, indicating enhanced dielectric efficiency and reduced energy dissipation. The capacitors' functionality was assessed through capacitance-frequency and conductance-frequency analyses. The capacitors exhibited stable high capacitance across a broad frequency spectrum, making them alternatives for energy storage solutions.

Broad temperature range with stable permittivity and low dielectric loss in (1–2x)Na0.5Bi0.5TiO3-xNaNbO3-xGdFeO3 system

High-temperature capacitors have garnered increasing attention in current research due to the inability of commercially available capacitors to meet the evolving industry demands. In this study, a Na0.5Bi0.5TiO3 based ternary system, denoted as [(1–2x)(Na0.5Bi0.5TiO3) -x(NaNbO3) -x(GdFeO3): x=0.01–0.09], was synthesised through solid-state reaction route. The influence of NaNbO3 and GdFeO3 on phase structure, dielectric, and ferroelectric properties are investigated. A fall of polar R3c phase % from X-ray refinement studies, diminishing macroscopic polarization, increasing breakdown strength, and flattening of temperature-dependent dielectric permittivity curves are perceived with the increase of substituent concentration. Temperature stable permittivity of (1–2x)(Na0.5Bi0.5TiO3) -x(NaNbO3) -x(GdFeO3) calculated ε'r/ε'r [250℃] at 1, 10, 100, 500 kHz with 10 % tolerance. Remarkably, (Δε′/ε′250°C ≤ ± 10 %) with x = 0.07 and 0.09 showed stable permittivity in the wide temperature range of (30°C to 600°C) at 500 kHz and a minimal dielectric loss (tan δ ≤ 0.01) measured at 250°C makes it a promising candidate for high-temperature dielectric capacitor applications.

Outstanding energy density and charge-discharge performances in Sr2KNb5O15-based tungsten bronze ceramics for dielectric capacitor applications

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 Sr2KNb5O15-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 (τ0.9 < 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 Sr2KNb5O15-based tungsten bronze relaxor ferroelectric ceramic can be one encouraging option in the dielectric energy storage field.

Enhanced breakdown strength and relevant mechanism of 0–3 type Sr0.7Bi0.2TiO3: Al2O3 composite ceramic with remarkable energy storage performances

In this work, a novel 0–3 type Sr0.7Bi0.2TiO3: Al2O3 composite ceramic is designed for dielectric capacitor applications. A superior energy density of 5.96 J/cm3, a high current density of 1099 A/cm² and a remarkable power density of 198 MW/cm³ are concurrently achieved in the ceramic specimen due to the great enhancement of the breakdown strength. The microstructure and physical property characterization confirm that highly insulating Al2O3 particles existed in the ceramic matrix. It is evident that reduced grain sizes, the enhanced band gap energy and the increased activation energy contribute to the improvement of the breakdown strength. Ulteriorly, numerical simulations reveal that the primary factor might be ascribed to the decreased grain size. These findings demonstrate that the 0–3 type Sr0.7Bi0.2TiO3: Al2O3 composite ceramic is a promising candidate for energy storage applications.

Dielectric and Electrical Behavior of Apraseodymium Based Tungsten Bronze Ceramics

AbstractThe ceramic oxide Na2Ba2Pr2W2Ti4Nb4O30 (NBPWTN) is prepared by a mechanical mixed oxide route. The compound formation and the phase are concluded from the x‐ray diffraction pattern taken at room temperature (XRD). The uniform distribution of grains of various sizes with negligible voids is studied from scanning electron micrograph of the sample pellet. The presence of dielectric dispersion and ferroelectric phase in the material is observed from the temperature‐dependent dielectric parameters at selected frequencies. The existence of ferroelectricity in the material is further confirmed by the room temperature hysteresis loop. Impedance spectroscopic studies informed about the correlation between the microstructure and electrical behavior. The frequency variation of AC conductivity refers to Jonscher's law. The temperature variation of frequency exponent term n indicates OLPT (overlapping large polaron‐tunneling) model of the conduction mechanism in the sample. NBPWTN is a strong candidate for applications involving thermistor‐related devices because of the temperature dependency of resistance. The value of temperature sensitivity coefficient β in our investigation is achieved between 2000 and 11 000 K, confirming that the material has a high‐temperature stability property and is ideal for high‐temperature electronics applications. The high room temperature dielectric constant value of the ceramic (around 500) is useful for dielectric capacitor applications.

Comparative analysis of the optical and electrical properties of PVA/PVP blended polymer with ZnCo2O4/CdS nanocomposites for optoelectronic and dielectric capacitor applications

Polymer nanocomposite blends were produced using solution casting, hydrothermal and thermolysis techniques. The blends were composed of a polymer blend consisting of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) as the organic host matrix with (1−x)ZnCo2O4–xCdS as filler samples. The current study investigated the morphological, structural, optical, and dielectric features of PVP/PVP/(1-x)ZnCo2O4/xCdS blends. The crystallite size and the phases formed in the fillers were obtained using Rietveld method. The structure and morphology of blended samples were studied using X-ray diffraction and scanning electron microscope techniques. The results of the optical properties imply that the linear and nonlinear optical parameters were affected by the amount of CdS in the (1-x)ZnCo2O4/xCdS filler samples. The direct allowed, indirect allowed, direct forbidden and indirect forbidden transitions values were reduced to 5.09, 4.55, 4.67 and 4.12 eV, respectively, as (1-x)ZnCo2O4/xCdS with x = 0.05 was incorporated into the PVA/PVP blend. The nature of electronic transitions in all blends were also studied. The fluorescence intensity, emitted colors and purity of the doped PVA/PVP blend are affected by the amount of CdS in the fillers and the excitation wavelength. The energy density of the host blend was improved as it loaded with fillers contained 5 and 10 % CdS in the frequency range beyond 1 kHz. The relaxation times of all doped blends were diminished except blend contained 25% CdS, the relaxation time rose slightly as compared with the relaxation time of undoped blend. The obtained properties indicates potential utility of the doped blends in photocatalytic, photonic, storage energy and optoelectronic applications.

A comprehensive study on structural, optical, electrical, and dielectric properties of PVA-PVP/Ag-TiO2 nanocomposites for dielectric capacitor applications

Nanocomposites made from polymers and nanoparticles (NPs) have a wide range of uses. Herein, the polymer nanocomposite electrolyte films were prepared by blending polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) with hybrid NPs of silver (Ag) and titanium dioxide (TiO2). The structural, optical, electrical, and dielectric properties of the resulting PVA-PVP/Ag-TiO2 nanocomposite electrolytes were analyzed. XRD analysis revealed that the PVA-PVP blend had a semicrystalline structure, and the addition of hybrid NPs reduced the crystallinity ratio. FTIR analysis showed that the intensity decreased as the content ratio of hybrid NPs increased. Optical measurements showed that the nanocomposite electrolyte samples' direct and indirect optical energy gap decreased with the increasing content of hybrid NPs. The electrical conductivity also increased with the hybrid NPs' content, likely due to the higher conductivity of the hybrid NPs compared to the polymer blend matrix's electrical conductivity. The dielectric constant (εr) and dielectric loss (εi) increased with the concentration of hybrid NPs at lower frequencies, indicating the polarization effects of space charges. The capacitance–frequency (C–f) and conductance–frequency (G/ω–f) curves of the prepared polymer nanocomposites exhibited a discernible enhancement correlating with the increased content of Ag-TiO2 nanofillers. The impedance spectroscopy data were analyzed using Nyquist plots, which showed a single semicircular arc whose radius of curvature decreased with increasing the hybrid NPs loading, indicating a decrease in the overall impedance of the nanocomposite electrolytes with the mixed NPs loading. The impedance reduction and dielectric feature increase were attributed to the interfacial polarization between the hybrid NPs and the polymeric matrix. These findings suggest that the PVA-PVP/Ag-TiO2 nanocomposite electrolytes could be used for thin-film dielectric capacitor applications.

Synthesis and investigation of structural, morphological and dielectric properties of Ba‐ordered BaTiO3 perovskite oxide

AbstractThe samples with A‐site cation ordering Ba1−x/2Ti1−xNbxO3 (BTN) with 0 ≤ x ≤ 0.010 were synthesized via the conventional ceramic route by calcining at 1200°C and sintered at 1350°C. The preliminary study of the phase of prepared samples was determined through X‐ray diffraction (XRD) analysis. The Rietveld refinement analysis indicates the tetragonal phase in BTN0 sample, whereas the doped samples exhibit a combination of tetragonal and cubic phases. Presence of Raman band at 308 cm−1 suggests the presence of tetragonal in all samples. The dielectric constant was observed to be 1500 (BTN0), 3000 (BTN5) and 1680 (BTN10) while tangent loss found 0.6 (BTN0), 0.04 (BTN5) and 0.07 (BTN10). All the sample shows same Curie temperature (120°C) due to Ba‐site cation ordering in the sample. Ferroelectric nature in all samples was also confirmed by modified Curie‐Weis law. Based on the current studies, the present materials can be explored as a potential candidate for ferroelectric‐memory devices, dielectric capacitor and energy harvesting applications.

Temperature‐stable Na0.5Bi0.5TiO3‐based ceramics with favorable low‐temperature dielectric and energy storage property

AbstractIn this work, (1 − x)(0.94Na0.5Bi0.5TiO3–0.06BaTiO3)–xKTaO3 (x = 0–0.30) ceramics are developed for dielectric capacitor applications. The introduction of KTaO3 from x = 0 to 0.30 increases the tolerance factor t from 0.984 to 1.005 and causes the decrease of ferroelectric rhombohedral phase in the ceramics. Besides, a gradual structural change toward a higher symmetry can be detected, accompanied by the obvious domain refinement. In the aspect of electrical property, the strengthened dielectric relaxation leads to the greatly enhanced thermal stability of dielectric response. The decline in Ts from 98 to −96°C causes a significant widening of the low‐temperature region with temperature‐stable dielectric constant εr and low dielectric loss tan δ. The x = 0.30 ceramic shows a high εr (25°C) of 1094 with the temperature coefficient of capacitance ≤±15% over −70 to 200°C, which exceeds the X9R standard. Meanwhile, tan δ is less than 0.02 in a wide temperature range of −35 to 300°C. In addition, the ultrafine grain size of 290 nm, large bandgap of 3.22 eV, and high resistance of the x = 0.30 ceramic contribute to its electrical breakdown strength. A linear‐like P–E loop with the large discharged energy density WD ∼ 3.50 J/cm3 and high energy efficiency η ∼ 90.1% is obtained under 28 kV/mm at room temperature. The thermal stability of the energy storage performance is also satisfactory with the variation of WD less than 15% over −40 to 200°C, and the η is higher than 85%.

A novel Sr5BiTi3Nb7O30 tungsten bronze ceramic with high energy density and efficiency for dielectric capacitor applications

Dielectric capacitors with high capacitive energy storage are urgently needed to meet the growing demand for high-performance energy storage devices. Herein, a novel lead-free Sr5BiTi3Nb7O[Formula: see text] (SBTN) tungsten bronze relaxor ferroelectric ceramic is prepared and explored for potential energy storage applications. A high recoverable energy density [Formula: see text] ([Formula: see text] 3.72 J/cm3) and ultrahigh efficiency [Formula: see text] ([Formula: see text] 94.2%) at 380 kV/cm are achieved simultaneously. Both [Formula: see text] and [Formula: see text] exhibit superior stabilities against temperature (30–140[Formula: see text]C), cycles (100 –105) and frequency (1–500 Hz). In addition, a high current density of 796 A/cm2 and a large power density of 71.7 MW/cm3 are achieved, together with good thermal endurance and fatigue resistance. These results demonstrate that the obtained SBTN ceramic can be deemed as the promising candidates for dielectric capacitor applications.

Simultaneously achieving large energy density and high efficiency in NaNbO3–(Sr,Bi)TiO3–Bi(Mg,Zr)O3 relaxor ferroelectric ceramics for dielectric capacitor applications

A large recoverable energy storage density of 7.59 J cm−3 and high energy storage efficiency of 81.3% are simultaneously achieved in NaNbO3–(Sr,Bi)TiO3–Bi(Mg,Zr)O3 relaxor ferroelectric ceramics.

(Bi0.5Na0.5)TiO3-based relaxor ferroelectrics with simultaneous high energy storage properties and remarkable charge-discharge performances under low working electric fields for dielectric capacitor applications

High energy storage and charge-discharge performances under low electric field are desirable for lead-free dielectric materials because of environmental hazards, the risk of high voltage and the high cost of insulation technology. Herein, lead-free ceramics based on 0.6BNT-0.4Sr0.775Bi0.15TiO3 (BNT-SBT) were designed, which simultaneously achieves a large energy storage density (Wrec~ 2.41 J/cm3) and a high efficiency (η~87.5%) under a low electric field of 190 kV/cm due to enhanced dielectric properties and the relaxation response. Moreover, the energy storage properties of the BNT-SBT ceramic exhibit moderate temperature stability, excellent frequency dependence, and cycling reliability. Furthermore, the charge-discharge performance simultaneously features a high power density (PD~51.4 MW/cm3), an ultrafast discharge speed (t0.9–77 ns), and remarkable stability against temperature and cycling. This study exploits a high-efficiency BNT-related ceramics with concurrently high energy storage and charge-discharge performances under low electric fields, which provides great potential in practical dielectric capacitor applications.

High energy and power density achieved in Bi0.5Na0.5TiO3-based relaxor ferroelectric ceramics with excellent thermal stability

Dielectric materials with large energy storage density and power density has been a sought-after goal. Here, we report new ceramic system (1-x) [0.5(Bi0.5Na0.5)TiO3-0.5SrTiO3]-x NaNbO3 exhibiting an excellent energy storage property (Wrec = 2.34 J/cm3, η = 74.6%). It is found that NaNbO3 incorporation can not only enhance the breakdown strength but also induce the formation of ergodic relaxation state, both benefitting the energy storage performance. Meanwhile, further research shows that the ceramic has excellent charge and discharge performance with high power density PD of 58.52 MW/cm3 and fast discharge speed t0.9 of 227 ns. Moreover, corresponding energy storage performance shows good cycle stability (1–10,000) and frequency stability (5–200 Hz), while the discharge performance exhibits excellent temperature stability (20–120 °C). These aforementioned merits reveal that of the relaxor ferroelectric 0.5BNT-0.5ST-0.03NN ceramic has great potential in practical pulse power dielectric capacitor applications.

Ultrahigh energy storage capacity with superfast discharge rate achieved in Mg-modified Ca0.5Sr0.5TiO3-based lead-free linear ceramics for dielectric capacitor applications

For the urgent demand of environmental protection and energy conservation, it is of great significance to develop environmentally-friendly dielectric ceramics with outstanding characteristic of energy storage and quick charge discharge capacity. For this study, we applied a strategy to achieve the enhancement of energy storage performance in (Ca0.5Sr0.5)1-xMgxTiO3 (abbreviate as CSMTx, x = 0.005, 0.010, 0.020, 0.040) linear ceramics based on the introduction of Mg2+ ion. Scanning electron microscopy and complex impedance measurement reveal that Mg2+ ion doping can refine grain size and increase grain boundary density, which results in grain boundary barrier strengthening owing to high-resistance grain boundaries. As a result, the marvellous energy storage properties, including an ultrahigh recoverable energy density of 2.88 J/cm3 combined with a giant energy efficiency of 90% are concurrently obtained in (Ca0.5Sr0.5)0.99Mg0.01TiO3 ceramic at an enhanced breakdown field (460 kV/cm). Meanwhile, this composition ceramic also exhibits the superior stability of frequency (1–1000 Hz) and temperature (20–100 °C) with minimal variation. In addition, the actual performance of ceramic capacitors in operation can be evaluated via the pulsed charge-discharge process. Delightedly, the superfast discharge speed (t0.9 = 20.4 ns), large current density (CD) of 421.23 A/cm2 and ultrahigh power density (PD) of 25.27 MW/cm3, as well as prominent thermal stability (20–100 °C) are synchronously produced in the CSMT2 ceramic. These merits qualify the unleaded linear ceramic as a competitive candidate for high-power capacitor applications, which offers a practicable approach for exploration on high-performance dielectric materials.

Energy storage and piezoelectric properties of lead‐free SrTiO3-modified 0.965Bi0.5Na0.5TiO3–0.035BaTiO3 ceramics

This manuscript reports the synthesis and piezoelectric properties of strontium titanate, SrTiO3-modified bismuth sodium titanate-barium titanate, 0.965Bi0.5Na0.5TiO3–0.035BaTiO3, (BNBT-xST, x = 0.00−0.30) ceramics produced by facile low temperature sol–gel and hydrothermal methods. Close inspection of the X-ray diffraction profile through Rietveld refinement indicates ST modification in BNBT leads to a phase transition from the dominant rhombohedral phase to a single tetragonal phase. This structural transition leads to enhancement of electromechanical and energy storage properties. A large dynamic piezoelectric coefficient (d*33 = 350 pC/V) was observed for BNBT-0.1ST sample. High energy storage density (Wrec = 0.37) and large energy storage efficiency (η = 75%) were observed at 75 °C for the BNBT-0.3ST sample. The energy storage response of the tunable ferrorelectric ceramics suggests their possible use for high-performance dielectric capacitor applications.

Electrocaloric cooling over high device temperature span

Summary Electrocaloric cooling demonstrates direct electricity utilization and high energy efficiency, and is often proposed as an environmentally benign, solid-state alternative to the conventional vapor compression cooling technology. As a result, the fabrication of effective electrocaloric materials and engineering of electrocaloric cooling devices have attracted increasing attention in the cooling community. However, the limited material adiabatic temperature change under safe operation field poses a major challenge to practical electrocaloric cooling device development, since real-world applications usually require device temperature span over 20 K. This perspective presents recent efforts devoted to design electrocaloric cooling devices based on active heat regeneration and cascading approaches; both strategies have achieved significant device temperature lift ~10 K with adiabatic temperature change of 2~3 K. The strategies discussed in this work are broadly applicable to the design of efficient and compact cooling systems.

Improved energy storage capacity in strontium and manganese co-doped 0.925(Bi1/2Na1/2)TiO3-0.075BaTiO3 ceramics

Inducing slimmer P-E loops while maintaining high ferroelectric polarization is a major challenge in dielectric capacitor applications. In this work, strontium (Sr) doped and strontium-manganese (Sr, Mn) co-doped 0.925(Bi1/2Na1/2)TiO3-0.075BaTiO3 (BNT7.5BT) ceramics were prepared to study energy storage performance. Sr-doped BNT7.5BT samples showed enhanced relaxor ferroelectric behavior and reduced remanent polarization (Pr) and coercive field (Ec) which can be attributed to the disruption of ferroelectric long-range order by the presence of non-polar cubic Pm3-m phase. (Sr, Mn) co-doped BNT7.5BT samples revealed improved energy storage density of 0.90 J/cm3 and thermal stability, affirming the vital role of Mn ions. The presence of MnTi″-VOoo defect-dipoles can create a dipole moment (PD) which can result in an internal field causing a constricted ferroelectric hysteresis loop with low Pr and Ec. Surface screening of polarization bound charges by Mn-induced defects affects the overall Pmax contribution to energy storage density.

Interfacial effect of Cu electrode enhanced energy density of amorphous aluminum oxide dielectric capacitor

In this work, a novel dielectric system of Cu/amorphous aluminum oxide/Pt (Cu/AmAO/Pt) is developed for dielectric capacitor applications. The high breakdown strength (425 MV m−1), high dielectric constant (8.6) and improved leakage current density are achieved due to this effective system. Dielectric capacitors with the structure of Cu/AmAO/Pt demonstrate much higher energy density of 6.9 J cm−3 than that of Au/AmAO (2.9 J cm−3). The enhanced performance of Cu/AmAO/Pt stems intrinsically from the interfacial effect under high electric field. The interfacial effect forms copper oxides and compacts the structure of AmAO, contributing to the improvement of breakdown strength and leakage current density. Anodized copper oxide also makes contribution to the increase of dielectric constant. Moreover, the oxidation mechanism is proposed for further understanding electrochemical behaviors. Based on the extensive applications of Cu in integrated circuits, high-energy-density Cu/AmAO/Pt system promises huge potential for the integrated circuit.

Fabrication of high quality factor cold sintered MgTiO3–NaCl microwave ceramic composites

Magnesium titanate is a well-known low loss dielectric ceramic, widely used in dielectric resonator and multilayer ceramic capacitor applications. But its high sintering temperature (1400°C) results in high energy consumption and thereby increases the environmental pollution and production cost. Furthermore, traditional sintering methods restrict co-sintering of ceramics with low melting metals and polymers. Cold Sintering Process (CSP) which provides a simple, effective and energy saving strategy for ceramic fabrication has not yet been reported for the fabrication of magnesium titanate based microwave dielectric ceramics. In the present work, dense samples of xMgTiO3-(1-x)NaCl (x = 0–0.5) ceramic composites were successfully prepared by cold sintering process (CSP) for the first time, at < 250°C, in 30 min,under a uniaxial pressure of 450 MPa. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) reveal that both MgTiO3 and NaCl co-exist in all the composites without any chemical reaction between the two phases. Raman spectra and scanning electron micrograph of MgTiO3 confirm the presence of MgTi2O5 as indicated by XRD. Relative permittivity (εr) of xMgTiO3- (1-x)NaCl composite increases and temperature coefficient of resonant frequency (TCF) decreases with increasing x; Qxf shows a non-linear variation with a maximum value of 29,500 GHz at x = 0.2. Results indicate that density, grain size and homogeneity of the particles influence the Qxf value of the composites. This study highlights the potential of cold sintering for the fabrication of MgTiO3 based composites with competitive microwave dielectric properties.

A novel lead-free Na0.5Bi0.5TiO3-based ceramic with superior comprehensive energy storage and discharge properties for dielectric capacitor applications

Na0.5Bi0.5TiO3 (NBT)-based ceramics have been widely used as dielectric materials for energy storage capacitors because of their environmental friendliness and excellent ferroelectric properties. However, their energy storage performance still needs to be further improved to satisfy the increasing demand. Herein, we report a novel 0.90(Na0.5Bi0.5)0.7Sr0.3TiO3-0.10Bi(Ni0.5Sn0.5)O3 (0.90NBST-0.10BNS) ceramic with significantly improved energy density (5.0 J cm−3), enhanced recoverable energy density (4.18 J cm−3) and high energy efficiency (83.64%) through the incorporation of Bi(Ni0.5Sn0.5)O3 (BNS), due to the increased breakdown strength and the relaxation ferroelectric (RFE) properties. The first-order reversal curve (FORC) measurements confirm that the addition of BNS improves RFE properties by breaking the order of long-range ferroelectricity. The 0.90NBST-0.10BNS ceramic also possesses an outstanding temperature and frequency stability of energy storage properties in the range of 20 °C–140 °C and 1 Hz–100 Hz, respectively. More importantly, the discharge properties characterized by a preeminent power density (36.19 MW cm−3), transient energy release times (144.2 ns), and high discharge energy density (1.16 J cm−3) also synchronously observed in 0.90NBST-0.10BNS ceramic. These results show that the 0.90NBST-0.10BNS ceramic with outstanding comprehensive performances is a promising energy storage ceramic candidate for capacitors in high power systems.