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In the field of dielectric energy storage, achieving the combination of high recoverable energy density (Wrec) and high storage efficiency (η) remains a major challenge. Here, a high‐entropy design in tungsten bronze ceramics is proposed with disordered polarization functional cells, which disrupts the long‐range ferroelectric order into diverse polar nanoregions (PNRs) characterized by composition fluctuation and cation displacement. These PNRs lower the domain‐switching barriers and weaken domain intercoupling, thereby playing a key role in delaying polarization saturation, reducing energy loss, and enhancing the breakdown electric field (Eb). Benefiting from the synergistic effects, at a large Eb of 760 kV cm−1, breakthrough energy storage performance is realized in tungsten bronze ceramics, including a record‐high Wrec of ≈10.6 J cm−3, an ultrahigh η of ≈96.2%, and a record‐high figure of merit of ≈279. These developments, along with superior mechanical properties, stability, and charge–discharge performance, fully demonstrate the feasibility of this strategy for realizing structural‐functional integration in tungsten bronze ceramics. [ABSTRACT FROM AUTHOR]

As the share of air conditioning electricity consumption within total grid electricity consumption grows, the decomposition of such consumption becomes increasingly crucial for assessing electricity usage patterns, devising consumption scheduling strategies, and maintaining the stability of the power grid. Although there is a strong correlation between apparent temperature and air conditioning electricity consumption, the literature currently available seldom explores the impact of apparent temperature on this consumption. Moreover, there is a scarcity of effective assessment indices to evaluate the efficacy of air conditioning electricity consumption breakdown. This study introduces a method for decomposing electricity consumption from air conditioning units, utilizing effective duration as a basis to tackle these issues. By employing an apparent temperature model as a constraint, this approach identifies the effective operating time of air conditioning and constructs a constrained convex optimization problem to estimate air conditioning power usage. Additionally, a novel evaluation index for the effectiveness of air conditioning electricity consumption decomposition is proposed, which includes penalties for negative decomposed consumption, alongside the traditional consistency index. Comparative experiments are conducted using real electricity consumption data from Fujian Province. Empirical results indicate that the methodology for air conditioning electricity consumption decomposition presented in this paper aligns more closely with actual conditions. Furthermore, the evaluation metrics introduced for the decomposition of air conditioning electricity consumption are adept at precisely gauging the quality of the air conditioning electricity consumption data. [ABSTRACT FROM AUTHOR]

Superparaelectrics are considered promising candidate materials for achieving superior energy storage capabilities. However, due to the complicated local structural design, simultaneously achieving high recoverable energy density (Wrec) and energy storage efficiency (η) under high electric fields remains a challenge in bulk superparaelectrics. Here, we propose utilizing entropy engineering to disrupt long-range ferroic orders into local polymorphic distortion disorder with multiple BO6 tilt types and diverse heterogeneous polarization configurations. This strategy reduces the switching barriers, thereby facilitating the emergence of superparaelectric behaviors with ideal polarization forms. Furthermore, it enables high polarization response, negligible remnant polarization, delayed polarization saturation, and enhanced breakdown electric fields (Eb) in high-entropy superparaelectrics. Consequently, an extraordinary Wrec of 15.48 J cm–3 and an ultrahigh η of 90.02% are achieved at a high Eb of 710 kV cm–1, surpassing the comprehensive energy storage performance of previously reported bulk superparaelectrics. This work demonstrates that entropy engineering is a viable strategy for designing high-performance superparaelectrics. High-entropy superparaelectrics with locally diverse ferroic distortion simultaneously achieve ultrahigh energy density and ultrahigh energy storage efficiency under large electric fields. [ABSTRACT FROM AUTHOR]

High-voltage electric pulse rock boring (HVEPB) is a high-efficiency rock-breaking drilling technology, which is featured in high rock breaking efficiency and low cost. However, there is no suitable model to predict the high-voltage electric pulses rock-breaking process. First, this paper establishes a grain-based granite model based on Voronoi polygons, which can reflect the real characteristics of granite inhomogeneity. At the same time, based on the improved Wiesmann Zeller model, the electric breakdown channel model is established to simulate the rock electric breakdown discharge channel. Second, a high-voltage electric pulse rock-breaking model is established by combining the shock wave model in the previous research, which can completely predict the HVEPB rock-breaking process and study the influencing factors in the rock-breaking process. Finally, the HVEPB rock-breaking process and the effects of rock composition, electrode bit diameter, and mineral grain size on the rock-breaking are studied by simulation and experiment. The results show that the plasma channel heats up and expands in a quite short time to produce shock waves that act on the surrounding rock, forming crushing fractures and microcracks. Red sandstone is more efficient than granite in breaking rock and is crushed in a shorter period. An increase in drill diameter leads to a decrease in crushing depth and an increase in crushing range and energy utilization. As the mineral grain size decreases, more fractures and smaller grain-size rock debris are produced. The findings are of great importance to guide the commercial application of high-voltage electric pulse rock-breaking. Highlights: A simulation model of the electric breakdown channel is established. A prediction model for the entire process of high-voltage electric pulse rock-breaking is established. The process and the mechanism of high-voltage electric pulse rock-breaking are revealed. The effects of three factors on the high-voltage electric pulse rock-breaking process are studied. [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]

The possible mechanisms of electrical breakdown of transformer oil at low voltage values at alternating voltage were investigated. The formation of streamers from the surface of bubbles into a liquid dielectric after partial discharge in a bubble was detected. This phenomenon has been observed for bubbles in pure transformer oil, in transformer oil with the addition of carbon nano-tubes, in oil after operation. At very low voltages, streamers in transformer oil were registered if a partial discharge in the bubble was stimulated by X-rays. Three possible mechanisms of electric breakdown of a gap filled with transformer oil were revealed at low values of electric field strength in the range from 13 to 51 kV/cm. The appearance of streamers from bubbles was preceded by deformation of the bubble due to one or more partial discharges in it. Streamers always appeared in pairs from the poles of the bubble except for the case of the transformer oil with carbon nanotubes. The results obtained are important for understanding the mechanisms of breakdown of transformer oil at very low voltage and can explain the causes of a number of accidents in high-voltage installations. [ABSTRACT FROM AUTHOR]

High‐voltage electric pulse drilling technology has the advantages of high rock‐breaking efficiency, and low rock‐breaking energy consumption, which is one of the most promising rock‐breaking methods in geothermal drilling. However, there is insufficient understanding of the mechanism of high‐voltage electric pulse breaking of HDR under high‐temperature and high‐pressure environments (HTHP). In this paper, a numerical simulation model of electric breakdown under HTHP is constructed, and the whole process of high voltage electric pulse rock‐breaking and plasma channel generation is realized from the seven‐field coupling of circuit field, current field, magnetic field, breakdown field, heat transfer field, solid mechanics field and flow field. The temperature changes in the rock during the electric pulse rock‐breaking process were comprehensively analyzed, and the effects of different initial rock temperatures (200°C, 300°C, 400°C) and surrounding pressure conditions (30, 60, 90 MPa) on the high‐voltage electric pulse rock breaking law were considered. It is found that the thermal conductivity of the rock shows an increasing and then decreasing trend as the initial temperature of the rock increases, and that the thermal conductivity has a tendency to guide the development of plasma channels, and the radius of the plasma channels increases with the increase of the initial temperature of the rock. The heat transfer generated by high‐voltage electric pulse rock breaking is mainly in conduction, and the distribution shape of conduction heat is similar to the shape of the breakdown channel. The research in this paper can provide theoretical and technical guidance for developing electric pulse rock‐breaking technology. [ABSTRACT FROM AUTHOR]

Methyl ester is considered one of the alternative substitutes to mineral oil as an insulating liquid. This study investigates the dissolved gas analysis (DGA) of the methyl ester derived from palm oil, under low energy discharge faults. The aims are to understand the gas composition and evaluate the applicability of the well-established fault interpretation methods for mineral oil to the methyl ester. Experimental procedures were conducted based on the International Electrotechnical Commission (IEC) standards. It involved simulating electrical breakdowns in laboratory conditions as per IEC-156 standard and analyzing gas samples using gas chromatography based on IEC-567. Results show that methyl ester oils produce similar types of gases as mineral oils but at higher concentrations. The interpretation of DGA results using fault identification methods such as Duval Triangle, Duval Pentagon, and IEC ratio indicates an overestimation of fault severity in methyl ester oils, and categorizing the faults as high energy discharge. However, the key gas method correctly identifies the discharge in both methyl ester and mineral oils. These findings suggest the need for adjustments in existing DGA methods to account for the higher gas concentrations in methyl ester oils, for effective condition monitoring and maintenance of transformers if it was filled with methyl ester oil. [ABSTRACT FROM AUTHOR]

We are developing a phase-modulating micro mirror-array spatial light modulator to be used for real holography within the EU-funded project REALHOLO, featuring millions of pixels that can be individually positioned in a piston mode at a large frame rate. We found earlier that an electrostatic comb-drive array offers the best performance for the actuators: sufficient yoke forces for fast switching even at low voltages compatible with the CMOS addressing backplane. In our first design, the well-known electrostatic cross-talk issue had already been much smaller than would have been possible for parallel-plate actuators, but it was still larger than the precision requirements for high-image-quality holography. In this paper, we report on our analysis of the crucial regions for the electrostatic cross-talk and ways to reduce it while observing manufacturing constraints as well as avoiding excessively high field strengths that might lead to electrical breakdown. Finally, we present a solution that, in FEM simulations, reduces the remaining cross-talk to well below the required specification limit. This solution can be manufactured without any additional processing steps and suffers only a very small reduction of the yoke forces. [ABSTRACT FROM AUTHOR]

In order to improve the limited compatibility of existing polymer/ceramic dielectric composites and further enhance the energy storage density, MOF/polymer composite dielectrics have been explored, which exhibit good compatibility to the polymer matrix from abundant organic groups of the inorganic–organic hybrid metal-organic framework (MOF) fillers. However, they still lack a clear composition–structure–property rule, and the precise design of MOF fillers and polymer matrix becomes a prominent problem in these composites due to the diversity of the metal ions and the organic groups. Thus, in this paper, we present a series of formic acid MOFs/polylactic acid dielectric composites in which ferroelectric formic acid MOFs, namely PDLLA/[NH 3 (CH 2 ) 4 NH 3 ][M I I (HCOO) 3 ] 2 and PDLLA/[CH 3 NH 3 ][M I I (HCOO) 3 ] 2 , in which the formic acid MOFs are with different structures and different metal ions as fillers, including [NH3(CH 2 ) 4 NH3][MII(HCOO)3]2 (namely MOF– Co (M = Co), MOF– Mg(M = Mg), MOF– Mn (M = Mn), with 1, 4-butanediamine ion as guest) and [CH3NH3][M I I (HCOO)3]2 (namely MOF– Co 2 (M = Co), MOF– Ni 2 (Ni), with methylamine ion as guest). The composition and morphology of composite films were characterized by XRD, IR, SEM, DSC and UV, respectively, while the dielectric characterizations of the composites including the dielectric permittivity, the dielectric loss, the breakdown field strength and the energy density were also performed. The composition–structure–property relationships were also investigated including the influence of MOF content and MOF category. With the introduction of MOFs, the dielectric constant of the polylactic acid substrate was improved slightly while the breakdown field strength can be improved in some systems. Interestingly, the Co(II)-containing formic acid MOF has advantages over other formic acid MOFs with similar structure for the enhancement of the dielectric constant and breakdown field strength. Also, in some composite films with methylamine ion guest MOF fillers and low-MOF content (MOF– Co 2 (1 vol.%) and MOF– Ni 2 (1 vol.%)), the breakdown electric field enhanced significantly and further led to improved energy storage density which was about 43% higher than that of the polylactic acid matrix. The possible reason is that in these composites, the orientation of C–H bonds of MOFs seems more beneficial to the formation of hydrogen bonds between the carboxyl group of formic acid and the polylactic acid matrix. These relationships obtained from formic acid MOFs/polylactic acid composites are valuable to the design of high-performance polymer/MOF energy storage composites and may be a new perspective to the practical use of ferroelectric MOFs. [ABSTRACT FROM AUTHOR]

To verify the hypothesis of electrical hot spots (HSs)—channels of local electrical breakdowns—the analysis of the electrical properties of condensed explosives and the evaluation of the electric field strength in shock-loaded dielectrics are carried out. It is established that conditions for electrical breakdowns can be created in the compressed zone of explosives due to polarization phenomena (electric field) and shock-induced electrical conductivity (free electrons). The position of the electric model of detonation kinetics are formulated. The results of the experiments with liquid nitromethane (NM) and monocrystalline PENT are explained. [ABSTRACT FROM AUTHOR]

Thickness affects the electrical breakdown strength (EBD) of insulation materials, and the variation of EBD with thickness (d) is an important basis for insulation design. In this paper, the effect of d on three kinds of organic insulation materials (OIMs), namely polymethyl methacrylate (PMMA), polyetheretherketone (PEEK), and polyethylene terephthalate (PET), on their breakdown characteristics under microsecond pulse voltage (MSPV) was studied, and a breakdown probability prediction model was established based on Weibull distribution. The breakdown mechanisms of the OIMs under MSPV were also discussed. The results showed that the EBD of all three materials decreased with increasing d. The relationship between characteristic EBD and d all satisfied the inverse power model, and their inverse power coefficients were all close to 1/2.3, which was much larger than 1/8 for that under nanosecond pulse voltage. A general breakdown probability prediction model of the OIMs was established by combining the Weibull distribution and β = 2.3 so as to guide engineering design in the absence of basic test data under MSPV. The breakdown mechanism of the OIMs under MSPV was an energy-related composite physical breakdown mechanism, which was verified by analysis of energy accumulation characteristics and experimental evidence of the little influence of pulse width on EBD under MSPV. The research results lay the foundation for the insulation design and further study on the breakdown modeling of OIM under MSPV. [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]

The high‐voltage electric pulse fracturing (HVEPF) technology represents a novel and highly promising approach in rock fracturing. The investigation of thermal damage inflicted upon rocks by high‐voltage electrical pulses under multi‐physical field coupling is of great significance in the development of deep geothermal energy. This study establishes a damage model for rocks under electric fragmentation conditions by integrating electric field, heat transfer field, and solid mechanics field. Based on the developed damage model, the insulating properties, temperature variations, and forms of damage of rocks during electric fracturing are explored. Subsequently, the influence of voltage on rock damage status is investigated. The findings reveal that damage to the rock does not occur immediately after electrical breakdown; rather, it increases with the growth of current and temperature within the breakdown channel. Initial damage occurs at the ends of the breakdown channel, followed closely by damage in the central region of the channel. The predominant form of damage in rocks is tensile failure, with shear failure playing a secondary role, and the volume of damage increases with voltage. These results elucidate the characteristics of rock damage during electric fracturing, providing valuable insights for the engineering application of electric fracturing techniques. [ABSTRACT FROM AUTHOR]

As a vital material utilized in energy storage capacitors, dielectric ceramics have widespread applications in high-power pulse devices. However, the development of dielectric ceramics with both high energy density and efficiency at high temperatures poses a significant challenge. In this study, we employ high-entropy strategy and band gap engineering to enhance the energy storage performance in tetragonal tungsten bronze-structured dielectric ceramics. The high-entropy strategy fosters cation disorder and disrupts long-range ordering, consequently regulating relaxation behavior. Simultaneously, the reduction in grain size, elevation of conductivity activation energy, and increase in band gap collectively bolster the breakdown electric strength. This cascade effect results in outstanding energy storage performance, ultimately achieving a recoverable energy density of 8.9 J cm−3 and an efficiency of 93% in Ba0.4Sr0.3Ca0.3Nb1.7Ta0.3O6 ceramics, which also exhibit superior temperature stability across a broad temperature range up to 180 °C and excellent cycling reliability up to 105. This research presents an effective method for designing tetragonal tungsten bronze dielectric ceramics with ultra-high comprehensive energy storage performance. The authors improve the energy storage performance and high temperature stability of lead-free tetragonal tungsten bronze dielectric ceramics through high entropy strategy and band gap engineering. [ABSTRACT FROM AUTHOR]

Electric field on the surface of a metal electrode covered by a continuous dielectric film and immersed in plasma is calculated at negative electrode potential Ψ when parameter eΨ substantially exceeds electron temperature Te . It is established that strong electric field with a magnitude of 1–10 MV/cm can appear inside the film at plasma density of 1012–1013 cm–3 and electron temperature of Te = 10 eV as a result of charging of the outer film 10–1000 nm in thickness surface by a flux of positive ions from plasma. The magnitude of the electric field at film discontinuities is comparable to that inside the film. The magnitude of the electric field at the surface of the dielectric film and at the film-free clean metal surface in plasma is substantially lower than that inside the film. Strong electric fields inside the film and at its discontinuities can lead to electrical breakdown inside the film and at its discontinuities. The electrical breakdown of the dielectric film can initiate the unipolar arcing on metals, drive microplasma discharges and form centers of explosive electron emission on metal surfaces in plasma. [ABSTRACT FROM AUTHOR]

A system of equations with nonlinearity in the electric field potential and temperature is proposed for describing the heating of semiconductor elements on an electrical board with thermal and electrical breakdowns possibly arising over time. A method for numerical diagnostics of solution blow-up is considered. In the numerical analysis of the problem, the original system of partial differential equations is reduced to a differential-algebraic system, which is solved using a single-stage Rosenbrock scheme with complex coefficients. The blow-up of the exact solution is detected using an asymptotically sharp a posteriori error estimate obtained by computing approximate solutions on sequentially refined grids. The blow-up time is numerically estimated in the case of various initial conditions. [ABSTRACT FROM AUTHOR]

Owing to the intrinsic chemical disorder of microscopic composition, perovskite high‐entropy ceramics exhibit dielectric relaxation behaviors and are favorable for energy storage performance. In this work, (Bi0.2Na0.2Ca0.2Ba0.2Sr0.2)(Ti1−xNbx)O3 (BNCBST‐xNb, 0.01 ≤ x ≤ 0.25) ceramics were prepared using a hydrothermal method. The results indicate that Nb doping into BNCBST induces lattice expansion and deepens dielectric relaxation. Moreover, the BNCBST‐xNb ceramics exhibit a great enhancement of electrical breakdown strength (Eb) with Nb content, which results from the reduction of grain size, the increase of resistivity, the decrease of oxygen vacancies, and the enlargement of band gap width. Consequently, the BNCBST‐0.15Nb system presents an outstanding Eb of 497 kV/cm with excellent recoverable energy density (Wrec = 3.85 J/cm3) and efficiency (η = 87.7%), accompanying by the wide temperature stability (Wrec and η vary within ± 9.8% and ± 1.4% at 40–100°C) and fast discharge rate (t0.9 = 88 ns). The significant improvement of Eb and energy storage properties suggest that our research offers an effective strategy for developing lead‐free energy storage ceramics. [ABSTRACT FROM AUTHOR]

As one of the important electronic components, the dielectric capacitors for energy storage applications have been extensively studied in recent years. Among various dielectric materials, the perovskite oxide Bi0.5Na0.5TiO3‐based ceramics have become promising candidates due to their high polarization, dielectric tunability, environment‐friendly composition, and so forth. Herein, the relaxor ferroelectric ceramics of Bi0.5Na0.5TiO3–SrTiO3–Bi(Mg0.5Zr0.5)O3 were prepared via solid‐state reaction method. The sample with optimal composition not only retains the high polarization by introducing Bi3+ ions, but also achieves the reduced remanent polarization by enhancing relaxor behavior and the promoted electric breakdown strength by the grain size refinement. Accordingly, a high recoverable energy density of 8.3 J/cm3 under 450 kV/cm and the superb charge/discharge properties (current density CD = 1200 A/cm2, power density PD = 150 MW/cm3, charge/discharge time t0.9 = 0.15 µs) are achieved, revealing great prospect in energy storage applications. [ABSTRACT FROM AUTHOR]

Perovskite high-entropy ceramics (HECs) are favorable for energy storage performance due to the novel high-entropy effects. However, highly disordered states of HECs with equal molar ratio at the same site greatly reduce polarization intensity, yielding unsatisfactory energy storage properties. Herein, non-equiatomic [((Bi 0.5 Na 0.5) 0.94 Ba 0.06) 0.65 (Sr 0.5 Ca 0.5) 0.35 ](Ti 0.95 Me 0.05)O 3 (Me = Zr (Zr 0.5 Hf 0.5), (Zr 1/3 Hf 1/3 Sn 1/3), abbreviated as BNBSCT-Zr, BNBSCT-ZrHf, BNBSCT-ZrHfSn), HECs have been designed and prepared by a hydrothermal method. As-prepared HECs exhibit high maximum polarization, which are related to the morphotropic phase boundary (MPB) induced by the (Bi 0.5 Na 0.5) 0.94 Ba 0.06 TiO 3 composition. In addition, the A-site doping of Sr and Ca and B-site doping of Zr, (Zr 0.5 Hf 0.5), and (Zr 1/3 Hf 1/3 Sn 1/3) rooted in high configuration entropy improves the degree of dielectric relaxation, decreases the grain size, increases the resistivity, and enlarges the band gap, resulting in a higher breakdown electric field. As a result, BNBSCT-ZrHfSn ceramics exhibit the significant energy storage properties with a high W rec (6.44 J/cm3) and η (73.8 %) under a large E b (477 kV/cm), as well as good temperature, frequency, and fatigue stability. The results show that the "entropy engineering + MPB" strategy provided in this study can remarkablely develop the energy storage properties of dielectric ceramics. [ABSTRACT FROM AUTHOR]

Copper calcium titanate (CaCu 3 Ti 4 O 12 , CCTO) ceramics are receiving a great deal of attention for advanced electronic and energy storage device applications owing to their giant permittivity response and good temperature stability. However, the development and real applications of CCTO ceramics are generally restricted by their large dielectric loss and low breakdown electric field strength. In the present study, a novel type of perovskite-like Na 1/3 (Ca 1/2 Sr 1/2) 1/3 (Bi 1/2 Y 1/2) 1/3 Cu 3 Ti 4 O 12 (NCSBYCTO) ceramics were designed via multiple elements strategy based on the high-entropy concept. Consequently, all the NCSBYCTO ceramics present a giant permittivity response (103∼104), good stability of temperature and frequency, and remarkable relaxation characteristics, especially the NCSBYCTO ceramic sintered at 1050 °C exhibits a relative balance between the giant permittivity of about 7.0 × 103–9.5 × 103 and the lower dielectric loss of approximately 0.043–0.294 at a frequency range of 104–106 Hz under room temperature. Furthermore, all the NCSBYCTO ceramics present an obvious nonlinear characteristic. More encouragingly, a higher breakdown field strength of around 2552.56 V/cm accompanied by a larger nonlinear coefficient of about 6.48 is achieved in the NCSBYCTO ceramic sintered at 1070 °C. A significant electrical heterogeneity structure and electron defect structure induced by the existence of mixed-valence Cu+/Cu2+ and Ti3+/Ti4+ are also found in the NCSBYCTO ceramics. The giant permittivity response, low dielectric loss and improved nonlinear properties can be considered the synergistic effect of the defect mechanism and the internal barrier layer capacitor model. This finding offers a route for designing giant permittivity ceramics with brilliant dielectric properties and nonlinear behaviors, which is expected to benefit dual-functional device applications of capacitors and varistors. [Display omitted] • A novel type of Na 1/3 (Ca 1/2 Sr 1/2) 1/3 (Bi 1/2 Y 1/2) 1/3 Cu 3 Ti 4 O 12 perovskite-like ceramics were developed via multiple elements strategy. • All the NCSBYCTO ceramics exhibit a giant permittivity response (103∼104) and good stability of temperature and frequency. • A relative balance between the giant permittivity and a lower dielectric loss is achieved in the NCSBYCTO ceramic sintered at 1050 °C. • The NCSBYCTO ceramic sintered at 1070 °C shows a higher E b of 2552.56 V/cm and a larger α of 6.48. • The electron defect mechanism and IBLC model can synergistically explain the enhanced electrical properties. [ABSTRACT FROM AUTHOR]

The study aims to prepare modified glass fiber (mGF) through KH550 modified glass fiber (GF), aiming to enhance the mechanical and insulation properties of PA66 composites, and explore the effects of mGF content on the mechanical and insulation properties of PA66 composites. The results show that as the mGF content increases, the density of the composites shows a trend of first increasing and then decreasing. The tensile strength, elastic modulus, and notch impact strength all show a trend of first increasing and then decreasing. When the mGF content is 20%, the enhancement effect of various mechanical properties of PA66 composites is the strongest, with an increase of 13.38%, 19.23%, and 19.59% compared to the tensile strength, elastic modulus, and notch impact strength of pure PA66 composites, respectively. The electric field breakdown strength of PA66 composites shows a trend of first increasing and then decreasing under both DC and AC conditions. At the same time, the dielectric constant of PA66 composites shows a trend of first decreasing and then increasing, and reaches its lowest point at a dosage of 30%. The volume resistivity of PA66 composites shows a trend of first increasing and then decreasing, and reaches its highest value at a dosage of 20%, which is 3.34 x 1013 Ω·m. The mechanical and insulation properties of PA66 composites can be enhanced by adding 20% KH550 modified GF, which can be applied in the preparation of electrical circuit breaker materials. This material can be used as an electrical circuit breaker material. [ABSTRACT FROM AUTHOR]

As one of the important electronic components, the dielectric capacitors for energy storage applications have been extensively studied in recent years. Among various dielectric materials, the perovskite oxide Bi0.5Na0.5TiO3‐based ceramics have become promising candidates due to their high polarization, dielectric tunability, environment‐friendly composition, and so forth. Herein, the relaxor ferroelectric ceramics of Bi0.5Na0.5TiO3–SrTiO3–Bi(Mg0.5Zr0.5)O3 were prepared via solid‐state reaction method. The sample with optimal composition not only retains the high polarization by introducing Bi3+ ions, but also achieves the reduced remanent polarization by enhancing relaxor behavior and the promoted electric breakdown strength by the grain size refinement. Accordingly, a high recoverable energy density of 8.3 J/cm3 under 450 kV/cm and the superb charge/discharge properties (current density CD = 1200 A/cm2, power density PD = 150 MW/cm3, charge/discharge time t0.9 = 0.15 µs) are achieved, revealing great prospect in energy storage applications. [ABSTRACT FROM AUTHOR]

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The (Na0.5Bi0.5)TiO3 relaxor ferroelectric materials have great potential in high energy storage capacitors due to their small hysteresis, low remanent polarization and high breakdown electric field. In this work, (Na0.5Bi0.5)TiO3 thin films with ~400 nm were prepared on (001) SrTiO3 substrate by pulsed laser deposition technology. The (Na0.5Bi0.5)TiO3 films have good crystallization quality with a dense microstructure and relaxor ferroelectric properties, as confirmed by the elongated hysteresis loops and the relation of ∝Eα. A high Eb of up to 1400 kV/cm is obtained, which contributes to a good Wrec of 24.6 J/cm3 and η of 72% in (Na0.5Bi0.5)TiO3 film. In addition, the variations of Wrec and η are less than 4% and 10% in the temperature range of 20–120°C. In the frequency range of 103 Hz–2 × 104 Hz, the variations of Wrec and η are less than 10%. All those reveal the great potential of NBT film for energy storage. [ABSTRACT FROM AUTHOR]

The main aim of the present paper is to clarify the influence of the SF6 fraction in the SF6/N2 mixture on the breakdown voltage. For this, the two-dimensional axisymmetric fluid model coupled with the comprehensive mechanism of plasma chemical reactions is used. In addition, the influence of various parameters such as the voltage rise time and the SF6 fraction in the mixture is analyzed. It is observed that depending on the voltage rise time an admixture of only 1% of SF6 to N2 results in an increase in the breakdown voltage by 7%–43%. The sensitivity of breakdown voltage decreases with decreasing voltage rise time and is caused by the electron attachment time scale becoming comparable to the breakdown time. The results of simulations confirm that the increase in the SF6 fraction in the mixture leads to an increase in the breakdown voltage. This is explained by the influence of the SF6 fraction on the electron attachment rate coefficients rather than on the ionization reactions. [ABSTRACT FROM AUTHOR]

More than a decade of active electrocaloric (EC) material research has produced several EC materials that exhibit a giant electrocaloric effect (ECE) at high electric fields, which is assured by direct measurement. These EC materials have enabled the demonstration of EC cooling devices, which exhibit temperature lifts of more than 10 K. These research and development efforts have revealed the critical importance of electrical breakdown, which is common in all electric and dielectric materials and devices under high voltages and electric fields. In general, the electric field for reliable device operation of dielectrics has to be less than 25% of the typical electric breakdown strength. To realize EC cooling devices with competitive performance requires advanced EC materials that generate large ECE (ΔT > 5 K) under these low electric fields. Double-bond (DB) defect modified P(VDF-TrFE-CFE) relaxor polymers, as reported recently, generate large ECE under low electric fields without any fatigue effects even after 1 × 106 field cycles. These relaxor ferroelectrics promise to meet the application challenge. A closely coupled experimental and theoretical study of EC materials will undoubtedly lead to advanced EC materials that generate large ECE at low electric fields beyond the DB modified relaxor polymers. This will result in practical and high-performance EC coolers, which are environmentally benign, compressor-free, and highly efficient. [ABSTRACT FROM AUTHOR]

Bismuth sodium titanate (Bi0.5Na0.5TiO3)-based relaxor ferroelectric ceramics have received ever-increasing interest for their potential application in dielectric capacitors owing to their sterling energy storage capability. Herein, the perovskite end-member Ba(Fe0.5Nb0.5)O3 (BFN) was incorporated into 0.7Bi0.5Na0.5TiO3-0.3SrTiO3 (0.7BNT-0.3ST) ceramics to improve the relaxor characteristics and refine the grain, leading to slim polarization–electric field (P–E) hysteresis loops and enhanced electric breakdown strength. Particularly, the 0.85(0.7BNT-0.3ST)-0.15BFN ceramics achieved a high recoverable energy density of 5.7 J/cm3 and a high energy storage efficiency of 86.4% under a moderate electric field of 390 kV/cm. Additionally, remarkable stability in frequency, cycling, and temperature and excellent charge/discharge behavior were achieved at the same time. The above findings reveal that BFN-modified BNT-ST ceramics display greatly improved comprehensive energy storage properties, making them promising candidates in the field of electrostatic energy storage. [ABSTRACT FROM AUTHOR]

Copolymers based on vinylidene fluoride are potential materials for ferroelectric memory elements. The trend in studies showing that a decrease in the degree of crystallinity can lead to an unexpected increase in the electric breakdown field is noted. An analysis of the literature data reveals that in fluorine-containing ferroelectric polymers, when using a bipolar triangular field, the hysteresis loop has an unclosed shape, with each subsequent loop being accompanied by a decrease in the dielectric response. In this work, the effect of the structure of self-polarized films of copolymers of vinylidene fluoride with tetrafluoroethylene and hexafluoropropylene on breakdown processes was studied. The structure of the polymer films was monitored using infrared spectroscopy (IR) and X-ray diffraction. Kelvin probe force microscopy (KPFM) was applied to characterize the local electrical properties of the polymers. For the films of the first copolymer, which crystallize in the polar β-phase, asymmetry in the dielectric response was observed at fields greater than the coercive field. For the films of the copolymers of vinylidene fluoride with hexafluoropropylene, which crystallize predominantly in the nonpolar α-phase, polarization switching processes have also been observed, but at lower electric fields. The noted phenomena will help to identify the influence of the structure of ferroelectric polymers on their electrical properties. [ABSTRACT FROM AUTHOR]

This paper presents the results of numerical studies of the phase field model for the development of an electrical breakdown path. The model consists of Maxwell's equations in the quasi(electro)stationary approximation, the electric charge balance equation, and the Allen–Cahn equation describing the phase field evolution. Several problem settings concerning the development of a breakdown path in homogeneous as well as macro- and microheterogeneous media are considered. [ABSTRACT FROM AUTHOR]

Partial discharge (PD) is a localized discharge phenomenon in the insulator of electrical equipment resulting from the electric field strength exceeding the local dielectric breakdown electric field. Partial-discharge signal identification is an important means of assessing the insulation status of electrical equipment and critical to the safe operation of electrical equipment. The identification effect of traditional methods is not ideal because the PD signal collected is subject to strong noise interference. To overcome noise interference, quickly and accurately identify PD signals, and eliminate potential safety hazards, this study proposes a PD signal identification method based on multiscale feature fusion. The method improves identification efficiency through the multiscale feature fusion and feature aggregation of phase-resolved partial-discharge (PRPD) diagrams by using PMSNet. The whole network consists of three parts: a CNN backbone composed of a multiscale feature fusion pyramid, a down-sampling feature enhancement (DSFB) module for each layer of the pyramid to acquire features from different layers, a Transformer encoder module dominated by a spatial interaction–attention mechanism to enhance subspace feature interactions, a final categorized feature recognition method for the PRPD maps and a final classification feature generation module (F-Collect). PMSNet improves recognition accuracy by 10% compared with traditional high-frequency current detection methods and current pulse detection methods. On the PRPD dataset, the validation accuracy of PMSNet is above 80%, the validation loss is about 0.3%, and the training accuracy exceeds 85%. Experimental results show that the use of PMSNet can greatly improve the recognition accuracy and robustness of PD signals and has good practicality and application prospects. [ABSTRACT FROM AUTHOR]

Crosslinked polyethylene (XLPE) is an important polyethylene modification material which is widely used in high-voltage direct current (HVDC) transmission systems. Low-density polyethylene (LDPE) was used as a matrix to improve the thermal and electrical properties of XLPE composites through the synergistic effect of a crosslinking agent and nanopore structure molecular sieve, TS-1. It was found that the electrical and thermal properties of the matrices were different due to the crosslinking degree and crosslinking efficiency, and the introduction of TS-1 enhanced the dielectric constants of the two matrices to 2.53 and 2.54, and the direct current (DC) resistivities were increased to 3 × 1012 and 4 × 1012 Ω·m, with the enhancement of the thermal conductivity at different temperatures. As the applied voltage increases, the DC breakdown field strength is enhanced from 318 to 363 kV/mm and 330 to 356 kV/mm. The unique nanopore structure of TS-1 itself can inhibit the injection and accumulation in the internal space of crosslinked polyethylene composites, and the pore size effect of the filler can limit the development of electron impact ionization, inhibit the electron avalanche breakdown, and improve the strength of the external applied electric field (breakdown field) that TS-1/XLPE nanocomposites can withstand. This provides a new method for the preparation of nanocomposite insulating dielectric materials for HVDC transmission systems with better performance. [ABSTRACT FROM AUTHOR]

Ultrahigh electrostrain (S m) at low driving field in lead-free piezoceramics could alleviate key concerns by reducing energy consumption and the risk of electrical breakdown for advanced applications. However, the giant electrostrain always accompanied with an extremely large drive field is a long-standing conflict referred as the strain-electric field trade-off. Herein, we engineer a novel strategy of introducing the B-site unequal double doping cations (ZnSn 0.5)4+ into (Bi 0.5 Na 0.5) 0.93 Ba 0.07 TiO 3 ceramic to generate the spontaneous phase transition from relaxor state to ferroelectric state, polar nanoregions PNRs and defect cluster. The giant strain of S m = 1.12% is achieved by integrating the field-induced phase transition, morphotropic phase boundary MPB and the enhanced synergistic effect between the spontaneous polarization P s and the defect cluster polarization P d under a low electric field of 50 kV/cm, thus yielding extremely large piezoactuation constant d 33 * =2240 pm/V in (Bi 0.5 Na 0.5) 0.93 Ba 0.07 Ti 0.97 (ZnSn 0.5) 0.03 O 3 piezoceramics. This finding also demonstrates an unexpected new route to design novel ferroelectric materials via nonconventional mechanisms. [ABSTRACT FROM AUTHOR]

The emergence of stretchable electronic technology has led to the development of many industries and facilitated many unprecedented applications, owing to its ability to bear various deformations. However, conventional solid elastomer substrates and encapsulation can severely restrict the free motion and deformation of patterned interconnects, leading to potential mechanical failures and electrical breakdowns. To address this issue, we propose a design strategy of porous elastomer substrate and encapsulation to improve the stretchability of serpentine interconnects in island-bridge structures. The serpentine interconnects are fully bonded to the elastomer substrate, while segments above circular pores remain suspended, allowing for free deformation and a substantial improvement in elastic stretchability compared to the solid substrates. The pores ensure unimpeded interconnect deformations, and moderate porosity provides support while maintaining the initial planar state. Compared to conventional solid configurations, finite element analysis (FEA) demonstrates a substantial enhancement of elastic stretchability (e.g. ≈9 times without encapsulation and ≈ 7 times with encapsulation). Uniaxial cyclic loading fatigue experiments validate the enhanced elastic stretchability, indicating the mechanical stability of the porous design. With its intrinsic advantages in permeability, the proposed strategy has the potential to offer insightful inspiration and novel concepts for advancing the field of stretchable inorganic electronics. [ABSTRACT FROM AUTHOR]

A thorough understanding of arc discharge mechanism as well as determination of arc discharge voltage at the nanometer scale remains challenging due to the complexities associated with electrode preparation and precisely maintaining nanoscale separations in experiments. This work addresses this challenge through a novel approach by accurately measuring electric breakdown/discharge voltages between Pt-coated Si electrodes with separations ranging from ∼5 nm to 370 nm using a combination of fixed and flexible nano-electrodes while inherently creating an ideal environment to mitigate the effect of mechanical vibrations on the measurement results. For separations of 10, 100, and 300 nm, the corresponding discharge voltages are ∼15, 75, and 160 V, respectively, with the apparent electric field for the 10 nm separation exceeding 1.5 GV m−1. The results acquired from the investigated electrode configuration closely resembling the laterally actuated nanoelectromechanical system (NEMS) cantilever relays reveals strong agreement with NEMS relay breakdown characteristics, emphasizing the importance of arc discharge considerations while designing micro/nano electromechanical devices. Furthermore, deliberately applied arc discharge is shown to provide electrode nano-welding for realization of configurable NEMS circuits. [ABSTRACT FROM AUTHOR]

Polyimide (PI) films equipped on the surface of spacecraft are susceptible to ultraviolet damage. Herein, the performance of two kinds of polyimide films i.e. 3,3′,4,4′-biphenyl dianhydride-p-phenylenediamine (BPDA-PDA) and pyromellitic dianhydride-4,4′-oxydianiline (PMDA-ODA) under vacuum ultraviolet (VUV, 172 nm) irradiation was studied. The failure behavior of the PI films was studied by tensile tests, thermogravimetry (TGA), thermomechanical analysis (TMA), electric breakdown, UV–visible transmittance and scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to analyze the molecular structure. The results indicated that the tensile strength of BPDA-PDA PI and PMDA-ODA PI films decreased by 10.4 and 7.4% under VUV irradiation, respectively; the breakdown strength and UV-transmittance also deteriorated. Besides, the surface morphology of the PI films showed a large number of microcracks after VUV irradiation, which we ascribe to the breakage of imide rings (C-N-C) and ether bonds (C-O-C) of the PI films. However, the thermal stability (residual weight) of both PI films remained constant compared to the initial level; this can be explained by the combined effect of bond breaking and cross-linking of the polyimide films. [ABSTRACT FROM AUTHOR]

One way to increase the power of Brushless Direct Current (BLDC) motors is to switch to ferrite stator cores and increase the Pulse Width Modulation (PWM) frequency of Electronic Speed Controllers (ESC). This is particularly important in UAVs, where the weight of BLDC motors and their specific power are critical. The main problem when operating at high PWM frequency is that all parallel-connected MOSFETs should turn on quickly and in perfect synchronism. Nonsynchronization of transistors leads to thermal or electrical breakdown. The paper proposes new circuit solutions that ensure synchronous operation of high-power MOSFET transistors in the output stages and allow increasing the PWM frequency of Electronic Speed Control controllers (ESC) to 150-200 kHz. The use of ferrite cores in stators will significantly increase the power of BLDC motors while maintaining the same dimensions. Increasing the PWM operating frequency also allows multi-pole BLDC and PMSM motors to operate at higher speeds. The paper reveals a comprehensive methodology for constructing high-frequency ESC controllers for UAVs when switching to ferrite stator cores of BLDC motors. A special contribution is the description of the protective cascade circuits and the Battery Elimination Circuit (BEC) for powering the microprocessor part from a high-voltage current source. [ABSTRACT FROM AUTHOR]

Electric motors are widely applied as electrical equipment that rotates at high speeds in high-temperature and high-voltage environments, with epoxy resin being the main material used to reinforce the structure of the motor. Taking epoxy resin as the research object in this work, comprehensive analysis was carried out to investigate its various physical properties. The frequency conversion dielectric performance of epoxy resin was tested and its perforation morphology was analyzed. The test results were used as corresponding parameters to establish a combined model of electrical and thermal breakdown for the reinforced structure. The dynamic performance, static mechanical performance, and stress relaxation performance of the epoxy resin at different temperatures were also tested, and a viscoelastic constitutive model of epoxy-reinforced structures was established and verified through stress relaxation tests. The research results of the breakdown and viscoelastic models can serve as a reference for the application of epoxy resin-reinforced structures. [ABSTRACT FROM AUTHOR]

Single zinc oxide nanowires (ZnO NWs) are promising for nanogenerators because of their excellent semiconducting and piezoelectric properties, but characterizing the latter efficiently is challenging. As reported here, an electrical breakdown strategy was used to construct single ZnO NWs with a specific length. With the high operability of a nanomanipulator in a scanning electron microscope, ZnO-NW-based two-probe and three-probe structures were constructed for fabricating AC/DC nanogenerators, respectively. For a ZnO NW, an AC output of between −15.31 mV and 5.82 mV was achieved, while for a DC nanogenerator, an output of ∼24.3 mV was realized. Also, the three-probe structure's output method was changed to verify the distribution of piezoelectric charges when a single ZnO NW is bent by a probe, and DC outputs of different amplitudes were achieved. This study provides a low-cost, highly convenient, and operational method for studying the AC/DC output characteristics of single NWs, which is beneficial for the further development of nanogenerators. ARTICLE HIGHLIGHTS: HIGHLIGHTS • A method for reworking NWs to a specific length was achieved using an electrical breakdown strategy based on the constructed electrical loop, and its success rate is high. • With the maneuverability provided by multiple operating units of a nanomanipulator, AC output was investigated for a single ZnO NW with a two-probe structure, as well as DC output with a three-probe structure. • In the three-probe structure, different DC outputs were achieved by changing the position of the NW–probe contact point and the wiring state of the probe, while the distribution of surface piezoelectric potential along the NW's axis was studied. [ABSTRACT FROM AUTHOR]

High-performance lead-free dielectric ceramics are key to energy storage ceramic capacitors. In this work, an effective strategy was adopted to improve the dielectric energy storage properties (ESP) of Bi 0.5 Na 0.5 TiO 3 based ceramics using CeO 2 doping. The introduction of Ce4+ refines the grain size and improves the dielectric temperature stability of the (1- x)Bi 0.4 Na 0.4 Ca 0.2 TiO 3 - x CeO 2 ceramics. However, Ce4+ is susceptible to reductive valence changes at high temperatures, forming defects that deteriorate the breakdown electric field strength (E b). To address this issue, Ce4+ valence transitions were successfully inhibited by sintering ceramics in an oxygen atmosphere. Remarkably, the E b value increases from 160 kV cm−1 for x = 0 wt% to 220 kV cm−1 for x = 0.8 wt%, and the total energy storage density increases from 1.38 J cm−3 to 2.99 J cm−3, as well as realizing a high energy storage efficiency (η ∼ 81 %). This study offers a framework for optimizing the performance of BNT-based energy storage ceramics and elucidating the precise link between valence variations and ESP. [ABSTRACT FROM AUTHOR]

This work aims to study the effect of Mn 2 O 3 additions on the electrical properties and microstructure characteristics of a SnO 2 -based ceramic varistor system doped additionally with Sb 2 O 5 , Cr 2 O 3 , and CoO. The specimens were prepared using conventional ceramic processing and homogenized by a high-energy ball milling system using the following composition: (98.99-X) % SnO 2 – 0.05% Cr 2 O 3 – 0.05% Sb 2 O 5 – 1.00% CoO – X% Mn 2 O 3 where X = 0.00, 0.05, 0.10, 0.20, 0.50 and 1% mol. Characterization by TG-DSC/DTA, XRD, XPS, and SEM/EDS, and the proposed chemical and defect-formation reactions allowed the conclusion that Mn 2 O 3 additions produce alterations of the microstructure consisting of the in situ formation of the spinel Co 2 MnO 4 secondary phase and modification of the potential barriers in the intergranular regions, where, in addition, oxygen vacancies are formed. With the 0.05 mol % Mn 2 O 3 , the grain size (average in the range of 2–3 μm) drops by 20 %, thus augmenting the grain boundaries. Altogether, this leads to a decrease in the nonlinearity coefficient (α) and an advantageous displacement of the breakdown electric field (E B). The 0.05 mol % Mn 2 O 3 specimen compares favorably with the reference material by surpassing the E B value by a factor of 8. Elucidation of Mn2+ and Co2+ in 1 mol % Mn 2 O 3 specimens by XPS suggests the role of MnO and CoO as intermediate phases, essential for Co 2 MnO 4 formation. The pathway for in situ formation of Co 2 MnO 4 is set forth based on the above characterization techniques in conjunction with proposed chemical and defect-formation reactions. [ABSTRACT FROM AUTHOR]

Designing high voltage superjunction (SJ) power devices with wide bandgap and extreme bandgap semiconductors, when compared to silicon, can enhance the trade-off between RON,sp and BV significantly, due to their >10× higher avalanche breakdown electric field. Nevertheless, because of the difference in the breakdown field profile and ionization path length, the effective breakdown field for these semiconductor SJ devices has not been determined theoretically. Consequently, we estimate and compare the effective critical breakdown electric field for SJ device structures in Si, 4H–SiC, 2H–GaN, β-Ga2O3, diamond, and AlN using Technology Computer Aided Design TCAD simulation. We also establish its dependence on the SJ devices' structural parameters, such as the pillar thickness. Furthermore, we also quantitatively compare the on-state performance of these SJ devices, including their thermal capabilities, using a paramount figure-of-merit to underscore the potential improvement possible. [ABSTRACT FROM AUTHOR]

The utilization of AgNbO 3 film in dielectric energy storage poses challenges due to its susceptibility to impurity phase formation, which compromises its antiferroelectric properties and breakdown electric field. In this study, we successfully fabricated an AgNbO 3 film with outstanding antiferroelectric properties and energy storage capabilities by employing oxygen ion surface plasma technology in conjunction with the sol-gel method. Our results demonstrate that the surface of the AgNbO 3 film undergoes a layer-by-layer treatment using oxygen ion plasma, effectively suppressing impurity phases and oxygen vacancies formation while reducing grain size and enhancing insulation performance. The AgNbO 3 film, which has undergone surface plasma treatment with oxygen ion, exhibits exceptional characteristics as an antiferroelectric material by demonstrating an impressive energy storage density of 13.13 J/cm3 and a high energy storage efficiency of 56%. Overall, we present a straightforward and viable approach for fabricating high-performance AgNbO 3 films for efficient dielectric energy storage. [ABSTRACT FROM AUTHOR]

The main factors that limit the practical application of bismuth ferrite-based energy storage ceramics are their low breakdown electric field strength and large remnant polarization. Here, we achieve high energy storage behavior in (0.72-x)BiFeO 3 -0.28BaTiO 3 -xLa(Mg 1/2 Zr 1/2)O 3 (BF-BT-xLMZ) ferroelectric ceramics through directional defect modulation based on a transformation of the conductance mechanisms. The systematic experimental analysis coupled with the vacancy sink model suggests that the introduction of LMZ changes the trap-filled-limit conduction mode dominated by oxygen vacancy, leading to 4 times enhancement of the breakdown electric field in BF-BT-0.2LMZ. Meanwhile, the induced nanodomains create a size effect that effectively reduces the remnant polarization, resulting in an increase in efficiency by 3.5 times. As a result, the recoverable energy storage density of the ceramic reaches an outstanding 4.2 J/cm3, together with a high efficiency of 75.2%. This work provides a feasible strategy for the development of ferroelectric family in the field of high-energy storage. [ABSTRACT FROM AUTHOR]

Gallium oxide (Ga 2 O 3) films have been the subject of recent scientific and technological research, owing to their outstanding characteristics. In this study, a rapid and efficient aerosol deposition (AD) process was utilized to produce Ga 2 O 3 films. The effect of the particle size distribution (PSD) of the columnar or plate-like Ga 2 O 3 starting powder on the dielectric, electrical, and microstructural properties of the films was also investigated. The dielectric constant and loss tangent of polycrystalline β -Ga 2 O 3 films fabricated using AD with narrow PSD Ga 2 O 3 powder were 10 and 6.7% at 10 kHz, respectively. In contrast, the films composed of a wide PSD powder exhibited a dielectric constant of 18 and a loss tangent of 3.6%. The leakage current densities of 1.77 × 10−5 and 6.63 × 10−7 A/cm2 at 5 V of the films using narrow and wide PSD powder were observed, respectively. In addition, the breakdown electric fields of the Ga 2 O 3 films with narrow and wide PSD powder were 1.15 and 1.06 MV/cm, respectively. Qualitative and quantitative analyses of the surface and inner microstructure were conducted to elucidate the differences in film characteristics according to the PSD. Consequently, a wider PSD enables the production of relatively denser and flatter high-quality films owing to enhanced hammering and crush effects. These results suggest potential applications of Ga 2 O 3 films fabricated using AD in various fields, such as capacitors, power semiconductors, and sensor devices. [ABSTRACT FROM AUTHOR]

After long-term operation of a generator, the stator winding will gradually experience aging or electrical corrosion, and scientific experimental analysis methods are needed to diagnose the health status of equipment. By analyzing the leakage current data of stator winding DC withstand voltage tests of multiple large tubular generators, this paper proposed an insulation performance evaluation method and measures to prevent winding breakdown; according to the electrical corrosion and high operating temperature of stator winding of wall mounted structure, we studied a series of innovative designs and processes for stator renovation, and conducted finite element simulation calculation of stator temperature field. The temperature rise test data shows that the operating temperature of the generator after stator modification is effectively reduced, and there is significant reduction in temperature deviation at each measuring point. The research results are close to the simulation calculation values, proving that the new process adopted for stator transformation is effective and feasible. [ABSTRACT FROM AUTHOR]

In this work, the single-event burnout (SEB) mechanism of p-GaN gate AlGaN/GaN HEMTs has been studied systematically. The irradiation experiment was carried out based on Ta ions with high linear energy transfer of 75.4 MeV/(mg/cm2), a standard criterion for commercial space applications. It is clearly observed that both the drain current and gate current increase during the irradiation. With the increasing drain bias, the device burns out eventually. Technology computer-aided design simulation was used to explore the possible burnout mechanism. The local high electric field peak induced by the electron and hole redistribution was proposed to explain the permanent damage. When heavy ions impact the device, electron–hole pairs are formed. With the aid of a horizontal electric field across the channel, electrons and holes move toward the drain and gate, respectively. The accumulation of electrons and holes around the drain edge and gate edge induces the local high electric field, which is even higher than the intrinsic breakdown electric field of GaN and AlGaN. The scanning electron microscope results verified the proposed SEB mechanism. This research offers significant theoretical and experimental insights for evaluating the reliability of GaN power devices against high-energy single-event burnout in aerospace applications. [ABSTRACT FROM AUTHOR]

Extensive research has been conducted on silver niobite (AgNbO 3)-based antiferroelectric ceramics for their promising applications in energy storage applications, with various compositional modifications explored to improve their energy storage capabilities. In this theoretical study, we have systematically investigated the electronic, structural, and chemical bonding properties of AgNb 1- x Ta x O 3 (x = 0.00, 0.125, 0.25, 0.375, 0.50, abbreviated as ANT100 x) solid solutions based on first-principles calculation. Our results reveal that the bandgap increases from 1.82 eV to 1.89 eV, due to the higher energy level of Ta 5 d orbitals compared to Nb 4 d orbitals. The enlarged bandgap, accompanied with oxygen vacancy formation energy (Δ E f , v a c ), contributes to the enhancement of E b. The Ta substitution of Nb site suppresses the cation displacement, oxygen octahedral distortion, and bond length and angles, indicating an improved stability of antiferroelectric phase. In addition, the electron localization function (ELF) and Bader charge values show weakened covalent bonding of Ta−O bonds compared to Nb−O bonds. These theoretical findings have the potential to aid in the advancement and creation of novel energy storage applications using lead-free AFE perovskites, as well as facilitate the manipulation of their breakdown electric field through bandgap engineering. [ABSTRACT FROM AUTHOR]

The electro-optical properties of methyl silicone oils with viscosities ranging from 10 to 10,000 cSt have been studied extensively to verify their suitability as immersion liquids. Immersion liquids are often used in nonlinear optics to protect hygroscopic crystals from moisture, reduce multiple reflections, and protect against electrical breakdown. However, the lack of experimental data makes it difficult to select an optimal liquid that does not exhibit a significant electro-optical Kerr effect in the fringing electric field around the electrodes on the crystal. Electro-optical measurements were performed using an improved dynamic polarimetric method, which compensates for the measurement errors caused by inaccurate positioning of the electro-optical modulator's operating point on its transmission characteristics. The values of the Kerr coefficient ranged from −8.83 × 10−16 to −6.79 × 10−16 m V−2 for all oil samples, at temperatures from 25 to 80 °C and frequencies from 67 to 1017 Hz. These exceptionally low values, together with a low dielectric constant, very good transparency, and high chemical stability, make methyl silicone oils highly suitable as immersion liquids. The Kerr coefficient and other electro-optical coefficients increased with increasing temperature. This unusual result cannot be adequately explained by Buckingham's molecular theory of the Kerr effect. [ABSTRACT FROM AUTHOR]