Advanced Pulsed Power Research Articles

Enhanced ultra-high efficiency in high-energy–density PbHfO3-based antiferroelectric ceramics through synergistic effect design

PbHfO3-based antiferroelectric materials with the giant power density and ultrafast charge–discharge performance have exhibited the potential application in advanced pulsed power microelectronic devices. Nevertheless, the huge challenge of the large driving field of the AFE-FE phase transition (EAFE-FE) accompanied by the poor breakdown electric strength (Eb) still exists up to now and further becomes a key bottleneck restricting the simultaneous realization of high energy storage density and efficiency. Hence, we report the synergistic effect to combine the tailor ABO3 perovskite structure for minimizing the electric hysteresis and increasing bandgap width to obtain the ultrahigh Eb. Rietveld refinements of the XRD patterns and Raman spectra experiments that demonstrate the average electronegativity and a redshift with the elevated Sr content attributable to enhancing bonding energy of cation-O bonds and antipolar ordering in crystalline structure, effectively resulting in stability of the PbHfO3-based antiferroelectric structure. Meanwhile, a ultrahigh Eb of 450 kV/cm is achieved owing to optimizing the average grain size and widening bandgap width. A remarkable energy storage density of 7.29 J/cm3 and record-high energy storage efficiency of 96.40 % are achieved via synergistic effect in (Pb0.93La0.02Sr0.04)(Hf0.475Sn0.475Ti0.05)O3 (PLS4HST) ceramics under respective maximum applied field. In addition, large power density of 173.40 MW/cm3 and excellent discharge energy density of 4.90 J/cm3 as well as fast discharge rate of 166.90 ns and superior frequency stability (1 ∼ 140 Hz), along with outstanding thermal stability (25 ∼ 150°C), have been simultaneously presented in PLS4HST ceramic. These results provide a good paradigm by synergistic effect designing for exploring high-performance dielectrics to meet the demanding requirements of advanced pulsed power electronic devices.

Physical Properties of CaTiO3-Modified NaNbO3 Thin Films.

NaNbO3(NN)-based lead-free materials are attracting widespread attention due to their environment-friendly and complex phase transitions, which can satisfy the miniaturization and integration for future electronic components. However, NN materials usually have large remanent polarization and obvious hysteresis, which are not conducive to energy storage. In this work, we investigated the effect of introducing CaTiO3((1-x)NaNbO3-xCaTiO3) on the physical properties of NN. The results indicated that as x increased, the surface topography, oxygen vacancy and dielectric loss of the thin films were significantly improved when optimal value was achieved at x = 0.1. Moreover, the 0.9NN-0.1CT thin film shows reversible polarization domain structures and well-established piezoresponse hysteresis loops. These results indicate that our thin films have potential application in future advanced pulsed power electronics.

Excellent energy storage properties in ZrO2 toughened Ba0.55Sr0.45TiO3-based relaxor ferroelectric ceramics via multi-scale synergic regulation

Lead-free ceramic capacitors offer ultrahigh power density and ultrafast discharging rates, making them critical energy storage components for advanced pulsed power systems. However, the greatest obstacle to broader applications remains the relatively low energy storage density. In this study, a relaxor ferroelectric ceramic based on (0.6-x)Ba0.55Sr0.45TiO3-0.4Bi0.5Na0.5TiO3-xSrZrO3 ((0.6-x)BST-0.4BNT-xSZ) is prepared using the tape casting method, resulting in an excellent energy density (Wrec ≈ 10.0 J cm−3) and high energy storage efficiency (η ≈ 91 %). The solid solution of linear dielectrics SrZrO3 synergistically regulates both relaxor properties and breakdown strength. The variation of relaxor property was explored utilizing New Glass model and the multi-polarization model, with confirmation provided by piezoresponse force microscopy. Furthermore, the breakdown strength could be attributed to improvements in electric insulation and the widening of the bandgap. As SrZrO3 content increases, the in-situ emergence of the second phase ZrO2, accompanied by a martensitic transformation, not only improves the fracture toughness of ceramics but also serves to elongate the breakdown path. Encouragingly, x = 0.20 ceramics also achieve excellent temperature stability (−95–125 ℃), frequency stability (1–1000 Hz), cycling reliability (1–106 cycles), and great charging-discharging properties. This multiscale synergic regulation strategy plays a guiding role in the screening of high-performance energy storage dielectric materials.

Biocompatible neem gum-modified polyvinyl alcohol composite as dielectric material for flexible energy devices

In our pursuit of a flexible energy storage solution, we have developed biocompatible (bc)-NG/PVA composite polymers by combining neem tree gum (NG) with polyvinyl alcohol (PVA). This innovative bio-inspired approach harnesses NG's unique properties for both the bio-electrolyte and bio-electrode components. The resulting bc-NG/PVA composites exhibit superior dielectric strength and versatility, surpassing traditional inorganic ceramic dielectrics in advanced electronics and pulsed power systems. Our study investigates the dielectric characteristics, conductivities, electric modulus, and impedance parameters of Pure PVA and NG-doped PVA composites. Adding 5 % NG to PVA significantly boosts its conductivity from 10−8 S cm−1 to 10−4 S cm−1, while the dielectric constant of PVA/5 % NG composite jumps to 104.5 compared to pure PVA. These improvements position the composite films of 5 % NG added PVA as promising materials for diverse applications. The heightened performance of these NG-blended PVA composite materials underscores their potential as a valuable resource for flexible energy storage solutions.

Optimizing electrical performance of low hysteresis Sr0.7Bi0.2TiO3 energy storage ceramic

Dielectric capacitors with rapid discharge rates and high power density are the basis for advanced pulsed power systems. Sr0.7Bi0.2TiO3 (SBT) is expected to be used in energy storage capacitors owing to the small hysteresis and high energy storage efficiency (η). Nevertheless, the low breakdown strength (BDS) limits the enhancement of energy storage density. This study explores the potential of Ho2O3-modified SBT to address this limitation. Introducing Ho reduces oxygen vacancies, decreases electrical conductivity, and increases thermal conductivity, thus enhancing BDS. The enhancement mechanism of electrical performance is studied through microscopic morphology analysis, structural refinement and numerical simulation. The Sr0.7Bi0.15Ho0.05TiO3 exhibits remarkable properties, including ultra-low loss tanδ (0.1 %), ultra-high η (95.8 %), and outstanding thermal, frequency, and cycling stability in energy storage properties. Additionally, Sr0.7Bi0.15Ho0.05TiO3 possesses a high power density (67.9 MW/cm3) and a rapid discharge rate (0.03 μs). The findings indicate that Sr0.7Bi0.15Ho0.05TiO3 is a prospective material for energy storage capacitors.

Breaking the Mutual Constraint between Polarization and Voltage Resistance with Nanograined High-Entropy Ceramic.

Dielectric ceramics with a high energy storage capacity are key to advanced pulsed power capacitors. However, conventional materials face a mutual constraint between polarization strength and the breakdown strength bottleneck. To address this limitation, the concept of nanograined high-entropy ceramics is introduced in this work. By introducing a large number of constituent elements into the A-site of perovskite material lattice, high-entropy (Bi0.2K0.2Ba0.2Sr0.2Ca0.2)TiO3-0.2 'CuO relaxor ceramic with nanoscale grains have been successfully prepared, which breaks the mutual constraint between polarization strength and breakdown strength bottleneck and results a recoverable energy density (Wrec ∼ 6.86 J/cm3) and an efficiency (η ∼ 87.7%) at 670 kV/cm. Moreover, its excellent stability makes it potentially useful under a variety of extreme conditions, including at high temperatures and high/low frequencies. These obtained results demonstrate that this nanograined high-entropy lead-free perovskite ceramic has great potential for energy storage applications.

A-site disorder induced ferroelectric to relaxor phase transition of Na(Nb0.75Ti0.25)O3 ceramics by Bi3+ for ultra-high energy storage properties

The present work introduces a new insight into effect of A-site disorder to develop the energy storage properties of Na(Nb0.75Ti0.25)O3 ceramic. Lead-free (Na1-xBix)(Nb0.75Ti0.25)O3 (x = 0.0, 0.05 and 0.1) (abbreviated as NNTBx) ceramics were synthesized using solid-state reaction technique. The introduction of Bi3+ shown a significant effect into the crystal structure, dielectric, ferroelectric and energy storage properties of NNT ceramics. The addition of Bi2O3 induced ferroelectric to relaxor phase transition with psedu-cubic crystal structure at 0.1. Significant inhibits of grain size to sub-micrometer has been achieved at 0.1 sample due to lower ionic radius of Bi+3 (1.34 Å, CN=12) to the ionic radius of Na1+ (1.39 Å, CN=12). Meanwhile, the dielectric constant increased from 300 to 1500 when the Bi3+-content increased from 0.0 to 0.1. Effectively increasing in maximum polarization (Pmax) and significant reducing in remnant polarization (Pr) resulting in increasing ΔP (Pmax – Pr) has been obtained at 0.1 content of Bi2O3. This enhancement is attributed to hybridization between Bi3+ 6Pand O2− 2P instead of Na1+ 2S and O2− 3S orbitals. On the other hand, the substitution of monovalent (Na1+) by trivalent (Bi3+) lead to create sodium vacancies into the A-sites of NNT lattice subsequently reducing the Pr value. The tolerance factor (τ) decreased from 0.955 to 0.953 when Bi2O3 increases from 0.0 to 0.1 indicate increasing the cations disorder, charge misfit and relaxor degree of NNT ceramics. The sample with 0.1 of Bi2O3 demonstrate remarkably high energy storage density (Wrec = 17.5 J/cm3), and high relatively energy storage efficiency (n = 80 %) at ultra-high dielectric breakdown strength (Eb = 700 kV/cm). Partially, (NNTB0.1) exhibit an outstanding stability of energy storage properties in terms of temperature (25 to 150 °C) and frequency (2–50 Hz). The variation of Wrec and n were observed about 1 % within the whole range of applied temperature and frequency. These results imply the high potential of (Na0.9Bi0.1)(Nb0.75Ti0.25)O3 ceramic in temperature-stable advanced pulsed power capacitor applications.

Engineering Hierarchical Interface in High-temperature Polymer Dielectrics for Electrostatic Supercapacitors

Dielectric capacitors are pivotal elements in advanced pulsed power devices and high-voltage high-capacity power electronic converters, crucial for efficient energy storage. However, a major challenge remains the significant reduction of...

Enhanced optical and energy storage properties of K0.5Na0.5NbO3 lead-free ceramics by doping Bi(Sr0.5Zr0.5)O3

Transparent relaxation ferroelectric ceramics with excellent transmittance and energy storage density are indispensable for efficient multifunctional coupling. These ceramics have found extensive applications in transparent energy storage electronics, advanced pulsed power capacitors, and optoelectronic multifunctional devices. In this study, we employed a combination of strategies to enhance the optical and electrical properties of ceramics. Specifically, the breakdown field strength of potassium sodium niobate (KNN) was increased by introducing Bi(Sr0.5Zr0.5)O3 (BSZ), which reduced the ceramic grain size. The incorporation of polar nano-micro-regions led to stronger local polarity fluctuations on the nanoscale, effectively minimizing the residual polarization. Furthermore, the forbidden bandwidth of the system was widened to mitigate photoelectron optical energy loss during transition.The newly developed ceramic, (1-x) KNN-xBSZ, exhibited remarkable performance characteristics, including an energy storage density of 4.13 J/cm3, a recoverable energy storage density of 2.95 J/cm3 at a low electric field of 245 kV/cm, and an energy storage efficiency of 84 %. Additionally, at 700 nm, the 0.875KNN-0.125BSZ sample displayed a transmittance of 52 %. Notably, this ceramic demonstrated high power density (PD = 36.76 MW/cm3) and rapid charge/discharge rates (t0.9 = 0.94 μs). Moreover, it exhibited excellent temperature and frequency stability, making it a dependable option for optoelectronic devices utilizing transparent relaxation ferroelectric ceramics.

Enhanced energy storage properties and good stability of novel (1–x)Na0.5Bi0.5TiO3–xCa(Mg1/3Nb2/3)O3 relaxor ferroelectric ceramics prepared by chemical modification

The increase in energy consumption and its collateral damage on the environment has encouraged the development of environment-friendly ceramic materials with good energy storage properties. In this work, (1–x)Na0.5Bi0.5TiO3-xCa(Mg1/3Nb2/3)O3 ceramics were synthesized by the solid-state reaction method. The 0.88Na0.5Bi0.5TiO3-0.12Ca(Mg1/3Nb2/3)O3 ceramic exhibited a high recoverable energy storage density of 8.1 J/cm3 and energy storage efficiency of 82.4% at 550 kV/cm. The introduction of Ca(Mg1/3Nb2/3)O3 reduced the grain size and increased the band gap, thereby enhancing the breakdown field strength of the ceramic materials. The method also resulted in good temperature stability (20–140 °C), frequency stability (1–200 Hz), and fatigue stability over 106 cycles. In addition, an ultrahigh power density of 187 MW/cm3 and a fast charge-discharge rate (t0.9 = 57.2 ns) can be obtained simultaneously. Finite element method analysis revealed that the decrease of grain size was beneficial to the increase of breakdown field strength. Therefore, the 0.88Na0.5Bi0.5TiO3-0.12Ca(Mg1/3Nb2/3)O3 ceramics resulted in high energy storage properties with good stability and were promising environment-friendly materials for advanced pulsed power systems applications.

Structural, dielectric, and morphological properties of (1-x)Ba0.65Sr0.35TiO3-xBi(Mg2/3Nb1/3)O3

Compared to other electrical energy storage devices, dielectric capacitors provide advantages like high power density, fast charge and discharge times, thermal stability, excellent mechanical strength, and a long cycling lifetime. Amongst the various dielectric materials, relaxor ferroelectric materials offer low remanent polarization and high energy efficiency. Previous research has shown that (i) doping Bi3+ ions into perovskite material can achieve improved results because its valence electronic configuration is close to that of Pb2+ and its ionic radius is also comparable to that of Ba2+, and (ii) introducing complex ions at the B-site can reduce the long-range ferroelectric order and result in the occurrence of polar nano regions.The present work aims at (i) incorporating both these strategies for the synthesis of the dielectric ceramic material and (ii) studying the structural, morphological, and dielectric properties of the prepared material. We have successfully synthesized (1-x) Ba0.65Sr0.35TiO3 – x BiMg2/3Nb1/3O3 with the help of a conventional solid-state reaction technique. The XRD analysis demonstrates the formation of cubic perovskite structure with space group Pm3m. The diffraction peaks shift towards lower 2θ angles with an increasing concentration of BMN, indicating a regular increase in unit cell volumes owing to the substitution of the smaller Ti4+ ions with bigger Mg2+ and Nb5+ ions. FESEM images illustrate the development of a homogeneous and dense microstructure. Element mapping analysis confirms the uniform distribution of all the elements within the prepared sample. From the dielectric measurements, we found that with the increase in doping, the dielectric peak broadens, and the frequency dispersion increases, indicating a rise in the relaxor behavior, which may be attributed to the increase in cation disorder due to the substitution of Bi3+ and [Mg2/3Nb1/3]4+ at the A- and B-site, respectively. The excellent dielectric properties indicate that (1-x)BST-xBMN is a promising ceramic material for use as a dielectric in capacitors for advanced pulsed power applications and consumer electronic devices.

Structural, dielectric and complex impedance analysis of Pb-free BaTiO3-Bi(Mg0.5Ce0.5)O3 ceramics

(1–x)BaTiO3–xBi(Mg0.5Ce0.5)O3 (0.00 ≤ x ≤ 0.10) ceramics were prepared via a solid-state sintering route to investigate their structural, dielectric, impedance and energy storage properties. Phase analysis revealed tetragonal to pseudo-cubic phase transition in compositions with x ≥ 0.06. Doping of BaTiO3 with Bi(Mg0.5Ce0.5)O3 decreased the average grain size from ≥ 10 µm to submicron level which decreased the electrical conductivity and increased the electrical breakdown strength up to 250 kV cm−1. The observed decrease in bulk resistance with an increase in temperature demonstrated a typical negative temperature coefficient of resistance-type behavior for these ceramics. The x = 0.08 composition exhibited a high energy storage density (∼1.84 J cm−3) with a recoverable energy density (∼1.26 J cm−3) and an electrical breakdown strength ∼250 kV cm−1. The obtained results demonstrate that this ceramic can be considered to be a good candidate for application in advanced pulsed power capacitors.

Improved energy storage property in polyvinylidene fluoride‐based multilayered composite regulated by oriented carbon nanotube@SiO2 nanowires

AbstractHigh‐performance dielectric capacitors are essential components of advanced electronic and pulsed power systems for energy storage. Because of their high breakdown strength and excellent flexibility, polymer‐based capacitors are regarded as auspicious energy storage material. However, the energy storage capacity of polymer‐based capacitors is severely limited due to their low polarisation and low dielectric permittivity. The modified Stöber method was used to construct two types of CNT@SiO2 (CS) one‐dimensional core‐shell structured nanowires with different shell thicknesses. By integrating the procedures of solution mixing, melt blending, hot‐stretching orientation and hot pressing, sandwich‐structured poly (vinylidene fluoride) (PVDF)‐based composites were fabricated. The CS core‐shell nanowires dispersed in the inter‐layer serve as electron donors, leading to a high permittivity, while two PVDF outer layers provide the favourable overall breakdown strength. The insulating SiO2 shell can effectively limit the migration of carriers and keep the dielectric loss at a relatively low level in the composites. The CS/PVDF composite exhibited an enhanced discharged density (~6.1 J/cm3) and breakdown strength (~241 kV/mm) when the interlayer filled with as small as 1 wt% CS nanowires with the SiO2 shell thickness of 8 nm, which is 203% and 18.7 % higher than pure PVDF (~2.01 J/cm3 at 203 kV/mm), respectively. This research presents a practical strategy for designing and fabricating advanced polymer film capacitor energy storage devices.

Achieving ultrahigh energy storage properties with superior stability in novel (Ba(1-x)Bix)(Ti(1-x)Zn0.5xSn0.5x)O3 relaxor ferroelectric ceramics via chemical modification

Relaxor ferroelectrics are receiving widespread attention due to their excellent energy storage properties (ESPs). In this study, (Ba(1-x)Bix)(Ti(1-x)Zn0.5xSn0.5x)O3 (abbreviated as BBTZS-x, x = 0.08, 0.10, 0.12, 0.14, 0.16, 0.18) ceramics were synthesized via a solid-state reaction route, and the effects of chemical modification on their structure and properties were investigated in detail. The introduction of Bi/Zn/Sn (BZS) elements into BaTiO3 (BT) systems induced the change from normal to relaxor ferroelectric behavior, which caused the enhancement of comprehensive ESPs. Significantly, BBTZS-0.12 ceramics acquired the preeminent total energy density (Wtot = 5.8 J/cm3), recoverable energy density (Wrec = 4.99 J/cm3) and efficiency (η = 86.1%) at high field strength of 550 kV/cm because of the existence of polar nanoregions (PNRs) therein. The dynamic response of PNRs to the external field was found to be propitious to the enhancement of energy-storage performance. In particular, excellent current density (CD = 721.5 A/cm2), power density (PD = 151.5 MW/cm3) and the time of release of up to 90% of the discharge energy density value (t0.9 = 53 ns) were simultaneously achieved in BBTZS-0.12 ceramics at 420 kV/cm. Moreover, BBTZS-0.12 ceramics were found to be the most optimal for the long-term applications under different environmental conditions because of their outstanding temperature (30–150 °C), frequency (1–500 Hz), and fatigue cycle (cycle numbers: 1–100000) stabilities. Therefore, exceptional ESPs make BBTZS-x ceramics promising for advanced pulsed power capacitors and energy storage applications.

A synergistic two-step optimization design enables high capacitive energy storage in lead-free Sr0.7Bi0.2TiO3-based relaxor ferroelectric ceramics

A two-step design is developed to realize multi-objective synergistic optimizations including high activity/ultrafine PNRs and ultrasmall grain size with compact grain boundaries, showing huge application potential in advanced pulsed power devices.

Superior Energy Storage Capability and Stability in Lead-Free Relaxors for Dielectric Capacitors Utilizing Nanoscale Polarization Heterogeneous Regions.

The development of high-performance lead-free dielectric ceramic capacitors is essential in the field of advanced electronics and electrical power systems. A huge challenge, however, is how to simultaneously realize large recoverable energy density (Wrec ), ultrahigh efficiency (η), and satisfactory temperature stability to effectuate next-generation high/pulsed power capacitors applications. Here, a strategy of utilizing nanoscale polarization heterogeneous regions is demonstrated for high-performance dielectric capacitors, showing comprehensive properties of large Wrec (≈6.39 J cm-3 ) and ultrahigh η (≈94.4%) at 700 kV cm-1 accompanied by excellent thermal endurance (20-160 °C), frequency stability (5-200 Hz), cycling reliability (1-105 cycles) at 500 kV cm-1 , and superior charging-discharging performance (discharge rate t0.9 ≈ 28.4 ns, power density PD ≈161.3 MW cm-3 ). The observations reveal that constructing the polarization heterogeneous regions in a linear dielectric to form novel relaxor ferroelectrics produces favorable microstructural characters, including extremely small polar nanoregions with high dynamics and multiphase coexistence and stable local structure symmetry, which enables large breakdown strength and ultralow polarization switching hysteresis, hence synergistically contributing to high-efficient capacitive energy storage. This study thus opens up a novel strategy to design lead-free dielectrics with comprehensive high-efficient energy storage performance for advanced pulsed power capacitors applications.

High Energy Storage Density in Nd(Zn2/3Nb1/3)O3‐Doped BiFeO3–BaTiO3 Ceramics

AbstractLead‐free ceramics with high recoverable energy density (Wrec) and energy storage efficiency (η) are attractive for advanced pulsed power capacitors to enable greater miniaturization and integration. In this work, a series of perovskite structured (1‐x)(Bi0.6Ba0.4)(Fe0.6Ti0.4)O3−xNd(Zn2/3Nb1/3)O3 (BF‐BT‐NZN) ceramics with high energy storage density through the solid‐state reaction method are successfully prepared, and the breakdown strength (Eb) and energy storage density are further improved by a membrane rolling process. The highest energy densities of the 0.94(BF‐BT)−0.06NZN ceramics are Wrec ≈ 5.6 J cm−3 and η ≈ 82.9%, which are due to the enhanced breakdown field intensity (BDS ≈ 400 kV cm−1) and the maximum polarization (Pmax≈ 38 µC cm−2). These results indicate that (1−x)(Bi0.6Ba0.4) (Fe0.6Ti0.4)O3−xNd(Zn2/3Nb1/3)O3 ceramics are high‐efficiency lead‐free materials for potential application in high‐energy‐storage capacitors.

Synchronously enhancing energy storage density, efficiency and power density under low electric field in lead-free ferroelectric (1-x)(Bi0.5Na0.5)0.7Sr0.3TiO3-xSr1/2La1/3(Ti0.7Zr0.3)O3 ceramics

Lead-free ferroelectric ceramics with outstanding energy storage properties (ESP) are considered as the most prospective candidates applied in advanced pulsed power systems (APPS). Nevertheless, the recoverable energy storage density (Wrec) and energy storage efficiency (η) are still difficult to be satisfied simultaneously. In this work, the lead-free ceramics were fabricated by doping Sr1/2La1/3(Ti0.7Zr0.3)O3 into (Bi0.5Na0.5)0.7Sr0.3TiO3 matrix (BNST-SLTZ) to optimize the ESP. The introduction of SLTZ induces the generation of polar nano regions (PNRs) to increase the proportion of weakly polar phase and flatten the dielectric peak, resulting in an effective decline of the remnant polarization (Pr). Furthermore, apparent grain size refinement is observed with the doping of SLTZ which enhances the breakdown strength (BDS). Excellent energy storage performances (Wrec of 2.06 J/cm3, η of 90.6%) are achieved under a low electric field of 170 kV/cm in the 0.90BNST-0.10SLTZ ceramic accompanying with good temperature (25–150 °C) and frequency (10–90 Hz) stability. Furthermore, an outstanding current density (CD of 976.15 A/cm2) and an ultrahigh power density (PD of 78.09 MW/cm3) are gained at 160 kV/cm. Therefore, the strategies of constructing PNRs and reducing grain size provide an achievable approach to exploit lead-free ceramics applied in APPS and improve the ESP of environment-friendly ferroelectrics.

High energy-storage density and efficiency in PbZrO3-based antiferroelectric multilayer ceramic capacitors

The utilization of antiferroelectric (AFE) materials is commonly believed as an effective strategy to improve the energy-storage density of multilayer ceramic capacitors (MLCCs). Unfortunately, the inferior energy conversion efficiency (η) leads to high energy dissipation, which severely restricts the broader applications of MLCCs due to the increased probability of materials and/or devices failure. Herein, AFEs featuring large polarization response and small hysteresis loss are proposed to make up for deficiencies. Guided by this proposal, (Pb0.94La0.04)(Zr0.69Sn0.30Ti0.01)O3 AFE MLCC (abbreviated as M2) are manufactured. An ultrahigh Wrec of 16.1 J/cm3 and an excellent η of 90.9% are achieved simultaneously. Additionally, a great discharge energy density (Wdis) of 8.8 J/cm3 and a large power density (PD) of 165.6 MW/cm3 are obtained synchronously. Noticeably, M2 exhibits excellent frequency-insensitive, temperature-bearable, and fatigue cycle-endurable energy-storage performances and/or charge-discharge properties. These results indicate that M2 has a promising prospect in advanced power electronic and/or pulsed power systems.

Concurrently Achieving High Discharged Energy Density and Efficiency in Composites by Introducing Ultralow Loadings of Core-Shell Structured Graphene@TiO2 Nanoboxes.

Polymer dielectrics have drawn tremendous attention worldwide due to their huge potential for pulsed power capacitors. Recent studies have demonstrated that linear/nonlinear layered composites, which can effectively balance energy density and efficiency, have huge potential for capacitive energy storage applications. However, further enhanced energy densities are strongly desired to meet the everincreasing demand for the miniaturization of electronic devices. Herein, a novel class of core-shell structured graphene@titanium dioxide nanoboxes is successfully synthesized and introduced into poly(vinylidene fluoride-hexafluoropropylene)-poly(ether imide) double-layer films. It is exciting to find that the introduction of merely 0.5 wt % nanoboxes results in a substantially enhanced energy density of 19.39 J/cm3, which is over 2.6 times that of the film without nanoboxes (7.44 J/cm3). Meanwhile, a high breakdown strength of 655 kV/mm and a high efficiency of 83% are achieved. Furthermore, the nanocomposites also show excellent power densities and cycling stabilities. These composites with excellent comprehensive energy storage performances have huge potential for advanced pulsed power capacitors.