Dielectric Strength Research Articles

Thermal and Mechanical Performances Optimization of Plaster–Polystyrene Bio-Composites for Building Applications

Polystyrene is renowned for its excellent thermal insulation due to its closed-cell structure that traps air and reduces heat conduction. This study aims to develop sustainable, energy-efficient building materials by enhancing the thermal and mechanical properties of plaster–polystyrene bio-composites. By incorporating varying amounts of polystyrene (5% to 25%) into plaster, our research investigates changes in thermal conductivity, thermal resistance, and mechanical properties such as Young’s modulus and maximum stress. Meticulous preparation of composite samples ensures consistency, with thermal and mechanical properties assessed using a thermal chamber and four-point bending and tensile tests. The results show that increasing the polystyrene content significantly improved thermal insulation and stiffness, though maximum stress decreased, indicating a trade-off between insulation and mechanical strength.

Study on the improvement of the insulation performance of polypropylene film by regulating TiO2-F by liquid phase grafting

Abstract According to the problem that the performance of film capacitors is limited due to the poor insulation of polypropylene film, a new nano-filler was studied and a polypropylene composite dielectric was fabricated. The breakdown strength of composite dielectrics was measured and the mechanism for improving their insulation properties was analyzed. In this paper, TiO2 with high dielectric constant is plasma-treated and then coated with a layer of polypropylene shell. TiO2 increases the dielectric constant of polypropylene film composite dielectrics, and shell-like polypropylene makes TiO2 more tightly bound to the polypropylene matrix. Compared with pure PP, the breakdown voltage of TiO2-F is increased by 18.7%, and the breakdown voltage of TiO2-F@PP-mah is increased by 40.5%, and the new nano filler greatly improves the insulation performance of PP. The experimental results show that TiO2 introduces a low-density trap, TiO2-F introduces a high-density deep trap, and the modification of PP-mah slows down the dielectric constant conflict, increases the compatibility between the nanoparticles and the matrix, and increases the trap energy level. Based on the analysis of experimental results with different mass fractions, this paper proposes the optimal filling ratio of the new core-shell, which provides a new method for the composite dielectric to improve the insulation performance.

Partial discharge characteristics of syntactic foam filled with hollow polymer microspheres

AbstractSyntactic foam materials, due to their advantages of low densities, low water absorption, and high dielectric strengths, have significant application potential in the cores of post insulators. However, because of a large number of microbubble structures within the syntactic foam, it might decrease the partial discharge inception voltage. It is necessary to investigate the partial discharge characteristics of the foam to assess the feasibility of its internal insulation application. In this study, the syntactic foam samples with four different microsphere contents (0%–2%) were prepared, and the physical structures of the materials were characterised by using Fourier transform infrared spectroscopy, scanning electron microscopy, and three‐dimensional computed tomography. Subsequently, finite element simulations of the electric field were performed to analyse the influence of the microsphere content and distribution on the internal electric field of the syntactic foam. The results suggested that both the microsphere content and distribution affected the partial discharge activity. When the microsphere content was low, the doping of microspheres essentially meant that more air gap defects were present, leading to a decrease in the partial discharge performance. However, when the microsphere content was high, the microspheres were distributed in a dense and orderly manner, improving the field concentration phenomenon and hence inhibiting the partial discharge to a certain extent. In conclusion, the findings of this study provide a data reference and theoretical support for the application of syntactic foam in the cores of composite post insulators.

Nanosecond Breakdown Characteristics of C4F7N and Various Mixtures at Pressures Above 1 Atmosphere in Comparison with SF6

This report evaluates the pulsed breakdown performance of C4F7N under a 6.8 kV/ns voltage excitation. The pulsed dielectric strength of C4F7N is compared to SF6 in the same experimental setup, and it is found that C4F7N concentrations of 50% or greater are required to achieve a dielectric strength greater than or equal to SF6. Pure C4F7N demonstrated higher electric field hold-off for longer time periods and less statistical variance under pulsed conditions when compared to SF6. Mixtures of 50%C4F7N with N2 or CO2 as buffer gases showed no appreciable difference in pulsed dielectric strength.

Superior Capacitive Energy Storage Enabled by Molecularly Interpenetrating Interfaces in Layered Polymers.

Polymer dielectrics are essential for advanced electronics and electrical power systems, yet they suffer from low energy density (Ue) due to their low dielectric constant (K) and the inverse relationship between K and breakdown stength (Eb). Here a scalable approach utilizing the designed molecularly interpenetrating interfaces is presented to achieve all-organic dielectric polymers with high Ue and charge-dischage efficiency (η). Distinctive intermolecular interactions and microstructural changes, as demonstrated experimentally and theoretically, are introduced by the molecularly interpenetrating interfaces, resulting in simultaneous improvements in dielectric responses and mechanical strength while inhibiting electrical conduction - outcomes unattainable in conventional layered polymers. Consequently, exceptional improvments in both K and Eb are achieved, yielding a very high Ue of 22.89Jcm-3 with η ≥ 90%, outperforming current layered polymer dielectrics. The bilayers can be easily fabricated into large-area films with high uniformity and outstanding capacitive stability (>500 000 cycles), offering a practical route to scalable high-Ue polymer dielectrics for electrical energy storage.

Preparation of modified epoxy resin with high hydrophobicity, low dielectric constant, toughness, and flame retardant by epoxy-functionalized siloxanes

A series of α, ω-dimethylglycidoxypropyl-terminated PDMS oligomer (PDMS-GE) oligomers with different polymerization degrees were synthesized and used to modify the bisphenol-A diglycidyl ether E51 (DGEBA) / 4,4-diaminodiphenylmethane (DDM) epoxy resin, resulting in epoxy resins with high hydrophobicity, low dielectric constant, good impact toughness, low combustion heat release rate, and low total heat release. The combustion heat release rate and total heat release of the material decreased with the increase in the loadings of PDMS-GE. Relative to pure epoxy resin, the composite E51/D30–10, which using DGEBA as the matrix, PDMS-GE with a degree of polymerization of 30 as the modifier in an amount of 10 phr relative to the mass sum of DGEBA, PDMS-GE and DDM, exhibited the best comprehensive performance with a water contact angle of 102.42°, a dielectric strength of 6.49 kV/mm, a dielectric constant of 2.93 at 14.2 GHz, the peak rate of heat release (PRHR) and total heat release (THR) are of 378.3 kW/m2 and 134.4 MJ/m2, respectively. These comprehensive performances underscore the potential of PDMS-GE oligomers in significantly improving epoxy resin properties. When the loadings of PDMS-GE oligomers are less than 5 wt%, PDMS-GE with a lower degree of polymerization can improve the toughness of epoxy resins. The impact strength of the composite E51/D24–5, which uses DGEBA as the matrix, PDMS-GE with a degree of polymerization of 24 as the modifier in an amount of 5 phr relative to the mass sum of DGEBA, PDMS-GE, and DDM, reaches 98.1 kJ/m2, which is about 28.9 % higher than that of pure epoxy resin. The results also indicated that the degree of polymerization of PDMS-GE oligomers has less influence on the dielectric properties and mechanical properties of composite materials.

Effects of Pulsed Electric Fields on the Elimination of Fusarium oxysporum in Greenhouse Soil

In greenhouses, high humidity, low light, and inadequate ventilation conditions, along with continuous and high-density planting, promote the proliferation of soilborne pathogens. Among these pathogens, Fusarium oxysporum Schltdl (F. oxysporum) is a notably challenging one, causing root rot of tomato plants in greenhouse cultivation. To address this issue, this study applied a pulsed electric field (PEF) to target the elimination of F. oxysporum in suspension and soil media. Initially, PEF parameters were systematically explored in suspensions to determine the effective ranges for the elimination of F. oxysporum. The results revealed that the effective ranges for achieving the desired microbial reduction were an electric field strength (EFS) between 5–15 kV·cm−1, a pulse number within the range of 100–500, and a pulse width of 10–20 µs. Subsequently, the impact of soil moisture content, soil bulk density, and soil type on soil dielectric breakdown field strength was analyzed within the range from previous results. Based on these findings, the soil experiments were conducted with parameters designed to prevent dielectric breakdown. Specifically, for sampling soil with a moisture content of 16.2% and a bulk density of 1.31 g·cm−3, the maximum effective application of electric field strength was 9.5 kV·cm−1, accompanied by 1000 pulses and a pulse width of 20 µs. Finally, building on these results, soil samples were sterilized within a parameter range that spanned an electric field strength of 5–9.5 kV·cm−1, a pulse number between 100–500, and a pulse width of 10–20 µs. Response surface methodology (RSM) analysis further identified the optimal parameter combination: an electric field strength of 8.2 kV·cm−1, 306 pulses, and a pulse width of 15 µs, resulting in an average lethal rate of 76.16% for F. oxysporum sterilization in soil. These findings suggest the potential use of PEF against F. oxysporum and other pathogens in greenhouse soils, and provide theoretical foundations for further experiments, thereby contributing to the sustainable advancement of greenhouse agriculture.

High Thermal Conductivity Polyelectrolyte Nanocomposite Electrical Insulation Thin Films

AbstractHigh‐power electronics require thin, conformal insulation that resists dielectric breakdown, while promoting removal of heat from the device. Recently, polyelectrolytes have shown promise in creating dielectric thin films, but their thermal conductivity remains relatively low (<1 W m−1 K−1). In this work, the layer‐by‐layer (LbL) assembly of polyethylenimine, mica clay, poly(acrylic acid), and hexagonal boron nitride is exploited to create a thin film dielectric material with relatively high thermal conductivity (through‐plane thermal conductivity of 1.87 ± 0.03 W m−1 K−1) and strong electrical insulation (breakdown strength of 152 kV mm−1). High thermal conductivity is obtained due to mica and hexagonal boron nitride nanoplatelets stretching through multiple layers. The performance benefits of this nanocomposite are demonstrated with a partial motor, where the nanocomposite greatly reduces the peak temperature of the motor when compared to state‐of‐the‐art polyimide insulation. This remarkable combination of thermal conductivity and dielectric breakdown strength represents a significant advancement in the electrical and thermal protection of high voltage devices.

Decoupling enhancements of breakdown strength and dielectric constant in PMIA-based composite films for high-temperature capacitive energy storage

Polymer-based dielectric films are increasingly demanded for capacitive energy storage. However, the negative coupling between dielectric constant (ɛr) and breakdown strength (Eb) presents a significant challenge to further enhancements, especially at high temperatures. Here, we propose dielectric composite films employing poly(m-phenylene isophthalamide) (PMIA) as the matrix, with nanodiamond (ND) particles modified by polydopamine (PDA) serving as reinforcing fillers. At 150 °C, the 1.0 wt% film demonstrates an ultrahigh discharge energy density (Ue) of 5.15 J/cm3 at a charge-discharge efficiency (η) exceeding 90 %. Even the temperature increases to 200 °C, the film maintains a desirable Ue of 2.36 J/cm3 with η > 90 %, achieving a record energy storage performance that outperforms numerous previous works. In addition to the inherent hydrogen bonds among PMIA molecular chains, ND@PDA fillers, enriched with hydroxyl groups, facilitate the formation of additional hydrogen bonds with PMIA, generating a hydrogen bonding network. This network provides additional dipoles for overall polarization, enhances Young's modulus for electromechanical resistance, and suppresses dielectric loss upon temperature increase, thereby reducing conduction loss. Both experimental and simulation results indicate that this hydrogen bonding network is extremely stable at high temperatures, effectively promoting the decoupling enhancements of ɛr and Eb for high-temperature energy storage applications.

Dielectric high gradient insulator – Progress towards multilayer insulating structures

High gradient insulators (HGI) consisting of ceramic and metallic alternating layer structure, have been shown to reduce surface breakdown occurrence in high voltage devices. Recently, the HGI's metal layers were replaced with high dielectric constant ceramics, creating dielectric high gradient insulators (DHGI) that were shown to outperform pure alumina analog. A 2-layer DHGI prototype manufactured by spark plasma sintering (SPS) demonstrated an increased surface breakdown field and fewer surface breakdowns during conditioning, compared to plain alumina. However, weak breakdowns at the opposite polarity were observed in the 2-layer structure. This study focuses on overcoming this issue by introducing a 3-layer design, with two high dielectric layers capping a plain alumina layer. Breakdown tests confirmed the elimination of weak breakdowns and improved dielectric strength, consistent with simulations predictions. Additionally, post-SPS air annealing was shown to be essential for removing adsorbed gases and recovering the high dielectric layers composition that changed during SPS. The annealed DHGIs were shown to reduce significantly the breakdown pulses during high-voltage conditioning. The 3-layer DHGI exhibited a 33.5 % higher breakdown field than plain alumina and a 13.5 % improvement over the 2-layer DHGI reported earlier.

Investigation On Barrier Layers Of PT/BaTiO3/PT Based Thin Film Capacitors

AbstractBarium titanate is a ferroelectric material used as a dielectric in thin film capacitors owing to its high dielectric constant. Barrier layers are utilized in these capacitors to improve the capacitors’ performance by controlling the microstructure and creating thin resistive films. In this paper, the effect of barrier layers in Pt/BT/Pt capacitors is studied using zinc oxide and aluminium oxide. The performance parameters such as capacitance density, leakage current, equivalent series resistance, dielectric loss and dielectric strength of Pt/BT/Pt thin film capacitors with barrier layers of different sizes are simulated using COMSOL Multiphysics modeling software. 2 nm thick aluminum oxide as Pt ‐ BT barrier layer gives optimal performance. The leakage current, dielectric loss, capacitance density, equivalent series resistance and dielectric strength of Pt/BT/Pt capacitor are found to be 0.519 mA, 9.62×10−12, 172.8 fF/μm2, 9.62 kΩ, 108 V/m respectively whereas that of Pt/ALO/BT/ALO/Pt capacitor are found to be 1.56×10−18 A, 7.81×10−18, 11.6 fF/μm2, 9.01×1015 Ω, 5.05×109 V/m respectively. The low capacitance in Pt/ALO/BT/ALO/Pt capacitor is due to the low dielectric constant of aluminium dioxide barrier layer. The reduced leakage current and increased equivalent series resistance is due to the low conductivity of the aluminium oxide barrier layer. The use of aluminium oxide barrier layer between the conductive surfaces can reduce the electric field and increase the breakdown voltage, leading to improved dielectric strength and reduced dielectric loss.

Algae-Derived Nacre-like Dielectric Bionanocomposite with High Loading Hexagonal Boron Nitride for Green Electronics.

The surging demand for electronics is causing detrimental environmental consequences through massive electronic waste production. Urgently shifting toward renewable and eco-friendly materials is crucial for fostering a green circular economy. Herein, we develop a multifunctional bionanocomposite using an algae-derived carbohydrate biopolymer (alginate) and boron nitride nanosheet (BNNS) that can be readily employed as a multifunctional dielectric material. The adopted rational design principle includes spatial locking of superhigh loading of BNNS via hydrogel casting followed by layer-by-layer assembly via solvent evaporation, successive cross-link engineering, and hot pressing. We harness the hierarchical assembly of BNNS and the molecular interaction of alginates with BNNS to achieve synergistic material properties with excellent mechanical robustness (tensile strength ∼135 MPa, Young's modulus ∼18 GPa), flexibility, thermal conductivity (∼4.5 W m-1 K-1), flame retardance, and dielectric properties (dielectric constant ∼7, dielectric strength ∼400 V/μm, and maximum energy density ∼4.33 J/cm3) that outperform traditional synthetic polymer dielectrics. Finally, we leverage the synergistic material properties of our engineered bionanocomposite to showcase its potential in green electronic applications, for example, supercapacitors and flexible interconnects. The supercapacitor device consisting of aerosol jet-printed single-walled carbon nanotube electrodes on our engineered bionanocomposite demonstrated a volumetric capacitance of ∼7 F/cm3 and robust rate capability, while the printed silver interconnects maintained conductivity in various deformed states (i.e., bending or flexing).

Enhanced dielectric breakdown strength and thermal conductivity of silicone gel composites with high-electron-affinity silicon Dioxide/Cationic Polymer/Nano-diamond

In order to address the contradiction that breakdown strength and thermal conductivity of materials are difficult to improve simultaneously, we report a novel calcined silicon dioxide/cationic polymer/nano-diamond (SD*@ND) filler with high electron affinity via self-assembled in-situ polymerization, electrostatic interaction and calcination technique. Subsequently, the calcined SD*@ND fillers are intercalated into the silicone gel to achieve a concurrent enhancement of electrically insulating properties and thermal conductivity of composites. For example, breakdown strength and thermal conductivity of the silicone gel composites with 20 wt% calcined SD*@ND are 17.97 kV/mm and 0.557 W/m·K, respectively. These results are remarkably higher than those (16.77 kV/mm, 0.211 W/m·K) of silicone gel usually used as a commercial packaging material of power devices. Meanwhile, it also shows excellent high-temperature electrically insulating properties. This work provides a scalable approach to developing a novel silicone gel composites with high performance.

Preparing porous calcium hexaluminate (CA6) ceramics with calcium aluminate cement (CAC) as the gelling agent and sole calcia source

Porous calcium hexaluminate (CA6) is attractive for thermal insulation due to low conductivity and chemical stability at high temperatures. In this study, porous CA6 ceramics were fabricated by a direct foaming method using calcium aluminate cement (CAC) as a gelling agent and sole calcia source. The results showed that the firing temperature is a significant factor in forming the CA6. In the samples fired at 1550 and 1650 °C, the main phase was CA6. Especially for samples fired at 1650 °C, the CA6 content was as high as 90 %. With the firing temperature increased, the compressive strength of the sample using tabular alumina and high-pure ultra-fine alumina was increased significantly, while the size of foamed spherical pores was decreased. In addition to the firing temperature, the type of raw alumina plays a key role in forming the CA6. The sample using high-pure ultra-fine alumina exhibited commendable comprehensive properties. The compressive strength is 5.12 MPa, and the thermal conductivity is 0.46 W·m−1·K−1. The work exhibited a simple process for producing porous CA6 ceramic with high porosity and commendable properties, including thermal insulation and compressive strength, using CAC as a gelling agent and sole calcia source.

Influence of bismuth content on the properties of glass-ceramics with composition xBi2O3-(0.40-x)B2O3-0.15ZnO-0.45P2O5: Synthesis, structural, thermal analysis, and dielectric relaxation process

The glass-ceramics materials with the sample composition of xBi2O3-(0.40-x) B2O3-0.15ZnO-0.45P2O5 (BBZP) (where x = 0.10, 0.15, 0.20, and 0.25) have been prepared using the conventional melt-quenching technique. Different nanocrystalline phases embedded inside the glass-ceramic matrix have been characterised by analysing x-ray diffraction spectra. The obtained density values as well as molar volume increases with the rise of bismuth content. The network structure of the glass ceramic samples has been investigated employing Raman spectroscopy. The DSC analysis reveals the decrease in Glass transition temperature (Tg) (433K–416K), and crystallisation temperature (Tc) (569K–556K) of the studied materials. The electrical properties of the samples have been investigated in the context of dielectric and modulus formalism. Different theoretical models have been employed to analyse the experimental data of dielectric and modulus spectra. The Nyquist plots of the materials have also been analyzed employing relevant models. It has been shown that the higher bismuth containing samples are highly dense with high thermal stability. Such materials also have high dielectric strength. Analysis of these performance indicators suggests the possible applications of these materials in electrochemical devices.

Innovative development of high-performance aerogel-phosphogypsum thermal insulation mortars: Optimization of composition and enhanced mechanical properties

This study investigates the effects of various components on the performance of aerogel-phosphogypsum (APG) thermal insulation mortar. This study investigates the effects of various components on the performance of aerogel-phosphogypsum (APG) thermal insulation mortar, with a special focus on optimizing the composition to enhance mechanical properties. The parametric range explored included phosphogypsum content from 10 to 30 wt%, hollow glass microspheres (HGS) from 5 to 15 wt%, and aerogel slurry from 40 to 80 wt%. Our findings reveal that the optimal composition, which provided the best balance between thermal insulation and mechanical strength, consisted of 20 wt% phosphogypsum, 10 wt% HGS, and 60 wt% aerogel slurry. Notably, the introduction of 0.14 % hydroxypropyl methylcellulose (HPMC) and 1.89 % re-dispersible polymer powder (RPP) significantly enhanced the compressive strength of the mortars. Specifically, compressive strength increased from an initial 0.05 MPa–0.27 MPa post-enhancement with HPMC and RPP. This research provides a detailed understanding of how individual components influence the formulation of APG and offers insights for optimizing the overall performance of aerogel-phosphogypsum composites, contributing to advancements in sustainable building materials.

Molecular Dynamics and Self-Assembly in Double Hydrophilic Block and Random Copolymers.

We investigate the self-assembly and dynamics of double hydrophilic block copolymers (DHBCs) composed of densely grafted poly[oligo(ethylene glycol) methacrylate] (POEGMA) and poly(vinyl benzyl trimethylammonium chloride) (PVBTMAC) parent blocks by means of calorimetry, small- and wide-angle X-ray scattering (SAXS/WAXS), and dielectric spectroscopy. A weak segregation strength is evident from X-ray measurements, implying a disordered state and reflecting the inherent miscibility between the host homopolymers. The presence of intermixed POEGMA/PVBTMAC nanodomains results in homogeneous molecular dynamics, as evidenced through isothermal dielectric and temperature-modulated DSC measurements. The intermixed process undergoes a glass transition at a temperature approximately 40 K higher than the vitrification of bulk POEGMA segments, and it shifts to an even higher temperature by increasing the content of the hard block. At temperatures below the intermixed glass transition temperature, the confined POEGMA segments between the glassy intermixed regions contribute to a segmental process featuring (i) reduced glass transition temperature (Tg), (ii) reduced dielectric strength, (iii) broader distribution of relaxation times, and (iv) reduced fragility compared to the POEGMA homopolymer. We also observe two glass transition temperatures of dry PVBTMAC, which we attribute to the backbone and side chain segmental relaxation. To the best of our knowledge, this is the first time in the literature that these glass transitions of dry PVBTMAC have been reported. Finally, this study shows that excellent mixing of the two homopolymers is obtained, and this implies that different properties of this copolymer system can be tailored by adjusting the concentration of each homopolymer.

Breaking dielectric dilemma via polymer functionalized perovskite piezocomposite with large current density output

Organometal halide perovskite (OHP) composites are flexible and easy to synthesize, making them ideal for ambient mechanical energy harvesting. Yet, the output current density from the piezoelectric nanogenerators (PENGs) remains orders of magnitude lower than their ceramic counterparts. In prior composites, high permittivity nanoparticles enhance the dielectric constant (ϵr) but reduce the dielectric strength (Eb). This guides our design: increase the dielectric constant by the high ϵr nanoparticle while enhancing the Eb by optimizing the perovskite structure. Therefore, we chemically functionalize the nanoparticles to suppress their electrically triggered ion migration for an improved piezoelectric response. The polystyrene functionalizes with FAPbBr2I enlarges the grains, homogenizes the halide ions, and maintains their structural integrity inside a polymer. Consequently, the PENG produces a current density of 2.6 µAcm−2N−1. The intercalated electrodes boost the current density to 25 µAcm−2N−1, an order of magnitude enhancement for OHP composites, and higher than ceramic composites.

Dielectric breakdown test of monolithic ceramic: Effects of electrode and sample thickness

To comprehend the mechanism of dielectric breakdown (DB) is fundamental for the work on improving the dielectric breakdown strength (DBS). Changing DB test in order to find the difference in DBS and DB channels is always one of the most important methods of studying mechanism of DB. In this paper, 6 different electrode set-ups were applied to the DB test of alumina ceramics with various sample thicknesses, and the effects of electrode and sample thickness were analyzed from the statistical characteristics of DBS data. Some phenomena were found: DBS first increased and then decreased with the increase of electrode size, and this could be attributed to the effect of electric field concentration and the area effect, and Weibull scaling law could be applied to analyze the area effect; the thickness-dependence of DBS was found in every electrode set-up, and none of the proposed mechanisms of DB could fully explain it; multi-layer series improved the high voltage resistance of alumina ceramic sheets, and the improvement factor was smaller than the predicted value on the base that the voltage-distribution ratio is equal in each layer.

Enhanced comprehensive energy storage properties of lead-free KNN based ceramics through composition optimization strategy

As one of the most potential lead-free dielectric capacitors in pulsed power systems, K0.5Na0.5NbO3 (KNN)-based ceramic possesses comparatively high dielectric breakdown strength (BDS) due to its particular submicron grains. Nonetheless, it is hard to improve both the energy efficiency η and the recoverable energy density Wrec of potassium sodium niobate ceramic at the same time. Herein, a composition optimization strategy is used, Bi(Li0.5Nb0.5)O3 (BLN) as a second component and NaNbO3 (NN) as a third component are introduced into KNN-based ceramic. It is corroborated that BLN content facilitates the growth of polar nano-regions (PNRs), and then strengthens the relaxation behavior, lows the remnant polarization Pr and upgrades the maximum polarization Pmax value of the ceramic. A transition from ferroelectricity to relaxation ferroelectricity occurred and an ultrahigh Wrec of 10.03 J/cm3 with a η of 64.15 % and the BDS of 1140 kV/cm are gained in KNN-0.100BLN-NN ceramic, Wrec of 8.25 J/cm3, η of 71.26 % and the BDS of 840 kV/cm are obtained in KNN-0.075BLN-NN ceramic. Besides, the KNN-0.075BLN-NN ceramic exists not only fine energy storage properties, but also high hardness and good temperature and frequency stability, confirming it’s a feasible material to be applied in pulsed power systems