Enhanced Breakdown Strength Research Articles

Exploring anti-ferroelectric thin films with high energy storage performance by moderating phase transition

Anti-ferroelectric thin films are renowned for their signature double hysteresis loops and sheds light on the distinguished energy storage capabilities of dielectric capacitors in modern electronic devices. However, anti-ferroelectric capacitors are still facing the dual challenges of low energy density and efficiency to achieve state-of-the-art performance. Their large hysteresis and sharp first-order phase transition usually results in a low energy storage efficiency and easy breakdown, severely obscuring its future application. In this study, we demonstrate that anti-ferroelectric (Pb0.97La0.02)(Zr1−xSnx)O3 epitaxial thin films exhibit enhanced energy storage performance through local structural heterogeneity to moderate the first-order phase transition by calculating the corresponding polarization as a function of switching time for the first time. The films exhibit remarkable enhanced breakdown strength (∼3.47 MV/cm, ∼5 times the value for PbZrO3) and energy storage performance. Our endeavors have culminated in the ingenious formulation of a novel strategy, namely, the postponement of polarization processes, thereby elevating the breakdown strength and total energy storage performance. This landmark achievement has unveiled a fresh vista of investigative opportunities for advancing the energy storage prowess of electric dielectrics.

Ultrahigh Capacitive Energy Storage in a Heterogeneous Nanolayered Composite

AbstractFerroelectric polymers with robust electrical polarization have been extensively investigated for capacitive energy storage. However, their inherent ferroelectric hysteresis loss limits the discharged energy density and compromises energy efficiency. Here, a heterogeneous nanolayered composite of ferroelectric polymer poly(vinylidene fluoride‐trifluoroethylene) (P(VDF‐TrFE)) and Al2O3 is presented, which effectively mitigates ferroelectric hysteresis loss while maintaining high polarization and enhanced breakdown strength. Phase‐field simulations indicate that the polarization behaviors of the heterogeneous layered structure are jointly influenced by the thickness and dielectric constant of each component, which balances the electrical energy and Landau energy within the heterogeneous system. Guided by the theoretical simulations, optimized polarization behaviors are achieved with a significant reduction in remnant polarization and ferroelectric loss in the P(VDF‐TrFE)/Al2O3 composites through careful control of P(VDF‐TrFE) thickness at nanometer scale. Moreover, the presence of multiple interfaces in the layered composites leads to a remarkable enhancement in polarization and breakdown strength. Consequently, an ultrahigh energy density of about 108 J cm−3 is achieved with a high charge–discharge efficiency of exceeding 80%. This work not only presents a straightforward approach to modify the polarization behaviors of ferroelectric polymers but also demonstrates a promising strategy for developing high‐energy‐density polymer nanocomposites.

Synergistic optimization of delayed polarization saturation and enhanced breakdown strength in lead-free capacitors for superior energy storage characteristics

High-performance dielectric energy-storage ceramics are indispensable core components in pulsed power systems. Despite progress in enhancing energy storage performance, there are still significant constraints among various macroscopic performance parameters, hindering their miniaturization and integration into devices. Herein, we propose a novel weakly coupled relaxor ferroelectric ceramic system that delays premature polarization saturation of BaTiO3-based ceramics to achieve the desirable energy storage characteristics. The ceramic exhibits a high energy storage density (Wrec) of ∼4.58 J cm−3 and high energy efficiency (η) of ∼95.2 % under an electric field of 540 kV cm−1, along with good performance stability in the range of 40–160 °C and 1–120 Hz. Furthermore, the enhanced insulation properties and refined average grain size contribute to the high breakdown field strength (Eb) of the system. These findings provide a viable framework for the design of dielectric ceramic capacitors with high energy-storage characteristics.

Achieving Significantly Boosted Dielectric Energy Density of Polymer Film via Introducing a Bumpy Gold/Polymethylsilsesquioxane Granular Blocking Layer.

Polymer dielectrics are the key materials for pulsed energy storage systems, but their low energy densities greatly restrict the applications in integrated electronic devices. Herein, a unique bumpy granular interlayer consisting of gold nanoparticles (Au NPs) and polymethyksesquioxane (PMSQ) microspheres is introduced into a poly(vinylidene fluoride) (PVDF) film, forming trilayered PVDF-Au/PMSQ-PVDF films. Interestingly, the Au/PMSQ interlayer arouses a dielectric enhancement of 47% and an ultrahigh breakdown strength of 704MVm-1, which reaches 153% of pure PVDF. It is revealed that the greatly enhanced breakdown strength originated from the Coulomb-blockade effect of Au NPs and the excellent insulating properties of PMSQ microspheres with a special molecular-scale organic-inorganic hybrid structure. Benefiting from the concurrently enhanced dielectric and breakdown performances, an outstanding energy density of 22.42Jcm-3 with an efficiency of 67.1%, which reaches 249% of that of the pure PVDF, is achieved. It is further confirmed that this design strategy is also applicable to linear dielectric polymer polyethyleneimine. The composites exhibit an energy density of 8.91Jcm-3 with a high efficiency of ≈95%. This work offers a novel and efficient strategy for concurrently enhancing the dielectric and breakdown performances of polymers toward pulsed power applications.

Magnetic-assisted alignment of nanofibers in a polymer nanocomposite for high-temperature capacitive energy storage applications.

Flexible polymer-based dielectrics with high energy storage characteristics over a wide temperature range are crucial for advanced electrical and electronic systems. However, the intrinsic low dielectric constant and drastically degraded breakdown strength hinder the development of polymer-based dielectrics at elevated temperatures. Here, we propose a magnetic-assisted approach for fabricating a polyethyleneimine (PEI)-based nanocomposite with precisely aligned nanofibers within the polymer matrix, and with Al2O3 deposition layers applied on the surface. The resulting polymer nanocomposite exhibits simultaneously increased dielectric constant and enhanced breakdown strength at high temperatures compared to pristine PEI. The enhanced dielectric constant is contributed by the depolarization effect of out-of-plane orientated nanofibers in composite films, while the surficial Al2O3 layers, with a wide bandgap, effectively prevent charge injection and transport at the electrode/dielectric interface. The optimally aligned composite films exhibit a significantly enhanced discharged energy density of 6.5 J cm-3 at 150 °C, with approximately 41% and 132% enhancement compared to random films and pristine PEI films, respectively. Additionally, a metalized multilayer polymer-based capacitor utilizing this composite film produces a high capacitance of 88 nF, while demonstrating excellent cyclability and flexibility at 150 °C. This work offers an effective strategy for developing polymer-based composite dielectrics with superior capacitive performance at elevated temperatures and demonstrates the potential of fabricating high-quality flexible capacitors.

Synchronously enhanced breakdown strength and energy storage ability of cellulose acetate flexible films via introducing ultra-low content of carbonized polymer dots

Developing green and environmentally friendly biomass materials for energy storage and application is of great significance to sustainable development. Novel composite films containing cellulose acetate (CA) and carbonized polymer dots (CPDs) are reported herein. The CPDs have strong hydrogen bonding interactions with CA matrix, in which CPDs act as the physical crosslinking points and enhance the entanglement density of the matrix. And the composite films demonstrate a significant enhancement in breakdown strength (Eb), reaching up to 520.58 MV/m with the addition of 0.1 wt% CPDs (1.62 times higher than 321.94 MV/m of pure CA). Furthermore, the discharging energy density (Ud) achieves 2.55 J/cm3 at 450 MV/m, which is 1.36 times higher than that of the pure CA film (1.87 J/cm3 at 400 MV/m) and simultaneously, the energy efficiency (η) is maintained at 73.3 %. The Coulomb-blockade effect induced by the ultra-low content of CPDs effectively inhibiting carrier migration, and the enhanced entanglement density of the matrix improving mechanical properties and reducing polarization loss, mainly contribute to the enhanced dielectric performances. Furthermore, CPDs also improve the mechanical properties of the composite films apparently. This work provides some references for the fabrication of the next generation of environmentally friendly dielectric composite films.

Engineering nanocluster and pyrochlore phase in BiFeO3-based ceramics for electrostatic energy storage

BiFeO3, known for its exceptional spontaneous polarization and high Curie temperature, stands as a pivotal component in power electronics. However, its relatively low breakdown strength has been a bottleneck in improving energy storage performance. Herein, we present an innovative approach to constructing nanoclusters and pyrochlore phases within BiFeO3-based ceramics. Specifically, the integration of the pyrochlore phase and nanoclusters (less than 10 nm) effectively reduces grain size and extends the growth path of electric trees, while imbuing the material with relaxor properties, which contribute to a significant enhancement in breakdown strength. As a result, this method achieves an ultrahigh energy storage density of 7.2 J/cm3 under 800 kV/cm, coupled with remarkable stability of temperature (20–180 °C), frequency (1–500 Hz), and fatigue resistance (over 10, 000 cycles). This work provides a viable pathway for the development of dielectric materials with superior energy storage performance to meet the stringent demands of advanced capacitor applications.

Interface engineering via non-thermal atmospheric plasma for highly tensile insulating epoxy-impregnated aramid composite paper

Epoxy-impregnated aramid composites, notable for their excellent mechanical and insulation qualities, are pivotal in electrical engineering and electronics. However, their performance is severely restrained by interface issues. This research proposes an effective modification strategy for improving interface property by employing non-thermal atmospheric plasma to introduce active functional groups onto aramid paper. The modified composites demonstrated a 26 % increase in tensile strength and a 20 % enhancement in breakdown strength at best, alongside inhibited charge transport properties and reduced partial discharge under operational electric fields. Molecular simulation suggests that plasma treatment bolsters interface hydrogen bonding, restricting the chain mobility of the resin molecular, and thus augmenting inter-phase compatibility. This study offers a factual perspective on improving resin-impregnated composites, laying a theoretical foundation for advancing high-performance materials in power industries.

Outstanding comprehensive energy storage performances in multiscale synergistic regulation-engineered (Bi0.5Na0.5)TiO3-based multilayer ceramics

Environmentally friendly dielectric ceramics with superior energy storage performances (ESP) are strongly demanded in pulsed power capacitor applications. Unfortunately, it is challenging to achieve simultaneously large recoverable energy density (Wrec), high Wrec/E (E as electric field) and broad operating temperature range in those ceramics. Herein we propose a multiscale synergistic regulation strategy to enhance comprehensive ESP of (Bi0.5Na0.5)TiO3 (BNT)-based ceramics. We introduce Ca(Zr0.8Ti0.2)O3 (CZT) into the BNT to increase atomic chaos and lattice distortion, which enhances relaxor behavior and lowers domain-switching barriers, thus effectively reducing remanent polarization. Besides, both suppressed oxygen vacancy and refined submicron grains improve extrinsic resistivity, which works synergistically with the enlarged intrinsic bandgap and multilayer structure design, producing substantially enhanced breakdown strength. Encouragingly, a very large Wrec of 13.4 J/cm3, an ultrahigh Wrec/E of 160 J/(kV∙m2), and a high efficiency η of 90.2 % are simultaneously achieved in the novel (Bi0.5Na0.5)TiO3-Ca(Zr0.8Ti0.2)O3 (BNT-CZT) multilayer ceramics, together with outstanding energy storage stability over a broad working temperature range (20–180 °C). The comprehensive ESP of our multilayer ceramics are superior to most of previously reported lead-free ones. This work provides a feasible pathway for substantially improving comprehensive ESP of lead-free ceramics, and also highlights advanced energy storage potential of the BNT-CZT for high-performance pulsed power applications.

Interfacial Origins of Electrical Breakdown Strength Enhancement in AlScN through Multilayer Structure

Interfacial Origins of Electrical Breakdown Strength Enhancement in AlScN through Multilayer Structure

Enhanced breakdown strength of epoxy composites by constructing dual-interface charge barriers at the micron filler/epoxy matrix interface

For the advanced energy systems with ultra-high voltage and frequency, in order to improve the thermal conductivity, arc resistance and mechanical strength of epoxy-based dielectric materials, the addition of micron inorganic fillers is necessary. However, this will inevitably degrade their breakdown strength. In this work, the example of constructing dual-interface charge barriers by optimizing molecular structure at micron filler/epoxy matrix interface to capture charge and then enhance the breakdown strength of epoxy composites is reported. Results show that the Al2O3@PVDF-6/BPA system with optimized interfacial structure exhibits the breakdown strength of AC and DC voltages of 37.5 and 67.8 kV/mm, respectively, far outperforming current epoxy composites containing micron fillers. The charge trapping effects in the dual-interface charge barriers are comprehensively investigated, which is confirmed to be the reason for the improved breakdown strength. In particular, the construction of dual-interface charge barriers hardly sacrifices the thermal and mechanical properties of epoxy composites. This work unveils a scalable approach to exploring satisfied dielectric epoxy composites by dual-interface charge barriers construction at the micron filler/epoxy matrix interface.

Entropy-assisted low-electrical-conductivity pyrochlore for capacitive energy storage

Capacitors with high energy storage performances are highly desired for the miniaturization, lightweight, and integration of high-end pulse systems. However, the trade-off between dielectric constant and breakdown strength restricts further performance optimization. To improve energy storage properties, a new tactic with rising attention, the high-entropy concept, has been demonstrated to suppress leakage current and enlarge the breakdown strength. However, the mechanisms connecting the insulation properties and entropy are still unclear. Herein, we successfully fabricated a series of entropy-modulated Cd2Nb2O7-based pyrochlore ceramics via the doping of multiple elements, and high-entropy pure pyrochlore was obtained due to the entropy-stabilization effect. Our results revealed that the insulation properties are distinctly enhanced via the enlarged carrier transport barriers and reduced carrier concentration, which should be attributed to entropy-induced large lattice distortion, grain-refining, and fewer defects. The optimized insulation properties significantly enhance breakdown strength from 148 kV cm−1 to 457 kV cm−1. A high energy density of 2.29 J cm−3 with a high energy efficiency of 88% is thus achieved in the high-entropy ceramic, which is 150% higher than the pristine material. This work indicates the effectiveness of high-entropy design in the improvement of energy storage performance, which could be applied to other insulation-related functionalities.

Achieving ultrahigh energy density and efficiency simultaneously in (Na, K)NbO3-based lead-free relaxor ferroelectrics via a collaborative design

Relaxor ferroelectrics have garnered enormous attention for their great application potential in pulsed power energy-storage capacitors, while simultaneously achieving large recoverable energy density (Wrec) and high efficiency (η) remains a formidable challenge. Through collaboratively controlling multiscale structure via a combination of composition design and processing improvement, polar nanodomains with multiple local symmetries were engineered in ultrafine grains, enabling significantly reduced polarization hysteresis, delayed saturation polarization, maintained high polarization, and enhanced breakdown strength. As a result, an excellent comprehensive energy-storage performance of Wrec ∼11.8 J/cm3 and η ∼88.7 % is achieved in the (Na, K)NbO3-based spark-plasma-sintered lead-free ceramics, together with stable charge-discharge properties of power density ∼176.3 MW/cm3, discharge energy density ∼3.2 J/cm3, and discharge time ∼43 ns over a wide temperature range of 20–140 °C. The studied ceramic demonstrates great advantages in advanced capacitive energy-storage applications.

High-temperature dielectric with excellent capacitive performance enabled by rationally designed traps in blends

Polymer dielectrics with excellent capacitive performance are urgently needed in advanced electrical and electronic systems. However, due to the dramatic increase in the conduction loss, the energy density and efficiency of polymers degrade severely at elevated temperatures, limiting their application in harsh environments up to 150 °C. Herein, an all-organic polyurea (PU)/polyetherimide (PEI) blend film is designed to prepare high-temperature polymer dielectric. It is found that carrier traps can be introduced by blending, and the hydrogen bond between PU and PEI increases the trap depth, leading to suppressed leakage current and enhanced breakdown strength, thus improving the energy storage performance. PU/30%PEI exhibits a high discharged energy density of ∼3.74 J/cm3 with an efficiency higher than 90% at 150 °C, which is 78% and 70% higher than pristine PU and PEI, respectively. This work provides a facile strategy to improve the energy storage performance of polymer dielectrics by introducing deep traps through blending.

Enhancing energy storage property of polypropylene‐based sandwich composites with surface‐modified nonzero dimensional nanomaterials

AbstractPolypropylene (PP) is a classical organic material for dielectric capacitor, exhibiting typical linear charge–discharge characteristics. However, its low energy density fails to meet the operating requirements of high‐power and energy storage systems. In this study, techniques such as spray‐coating, lamination hot‐pressing, melt blending, and in situ melt‐drawing are employed to fabricate PP‐based sandwich‐structured composite dielectrics. The outer layers consist of BN nanosheets (BNNSs)/PP composite, while the middle layer comprises Ba0.7Sr0.3TiO3@Polydopamine (BST@PDA)/PP. The introduction of BNNSs with a wide bandgap improves the breakdown strength of composites. BST@PDA increases the overall polarization of the composites and alleviates the local electric field concentration caused by hetero‐interfacial field distortion. When the filling concentration of BNNSs is 0.10 wt% and that of BST@PDA nanowires is 3 wt%, the composite demonstrates a high dielectric constant and low dielectric loss. Additionally, the sandwich‐structured composite, exhibiting a high charge–discharge efficiency of 97.80%, presents enhanced breakdown strength (Eb ~ 453 MV/m) and increased energy storage density (Ue ~ 5.67 J/cm3), which are 39.38% and 189.29% higher than neat PP (325 MV/m, 1.96 J/cm3), respectively. This study offers a viable and efficient approach to augment the energy storage density of PP‐based dielectrics.

Improved dielectric and energy storage capacity of PVDF films via incorporating wide-bandgap silicon oxide decorated graphene oxide

In this work, wide-bandgap silicon oxide decorated graphene oxide (GO@SiO2) hybrid was simply synthesized by in-situ hydrothermal method. The obtained GO@SiO2 as a filler was then introduced into poly (vinylidene fluoride) (PVDF) matrix to prepare GO@SiO2/PVDF composite dielectric films via solution casting method. A comprehensive dielectric and energy storage capacity of PVDF based dielectric films were simultaneously achieved, indicating synergistic enhancement of GO and SiO2. For the 0.2 wt% GO@SiO2/PVDF system, a relatively high dielectric constant (ɛ' = 12.9), an enhanced breakdown strength (404.9 kV mm−1) and an improved discharged density (5.7 J cm−3) were obtained, being 153 %, 111 % and 148 % higher than those of neat PVDF, respectively. Such study provided a new strategy in obtaining flexible and large energy storage dielectric films.

Achieving high energy-storage density and high temperature and frequency stability in 0.88BT-0.12BMT lead-free relaxor ferroelectric ceramics via NaNbO3 doping

In this work, 0.88BaTiO3-0.12Bi(Mg1/2Ti1/2)O3-xmol% NaNbO3 (x = 0, 0.5, 1, 1.5, 2) ceramics have been synthesized by using the traditional solid-state route. The effects of NaNbO3 on the phase structure, microstructure, dielectric, ferroelectric, and energy storage properties of the 0.88BaTiO3-0.12Bi(Mg1/2Ti1/2)O3 ceramics have been studied in detail. The ceramic doped with 1.5 mol% NaNbO3 exhibited a releasable energy storage density of 2.287 J/cm3, significantly higher than the undoped sample (1.194 J/cm3). The breakdown strength increases from 130 kV/cm for the undoped sample to 210 kV/cm for the sample doped with 1.5mol% NaNbO3. The enhanced breakdown strength of the 0.88BaTiO3-0.12Bi(Mg1/2Ti1/2)O3-xmol% NaNbO3 ceramics is primarily due to NaNbO3 doping, which produces a wider bandgap, smaller grain size, and higher specific resistance. The 0.88BaTiO3-0.12Bi(Mg1/2Ti1/2)O3-xmol% NaNbO3 ceramic's energy storage performance exhibits great temperature stability, frequency stability, and cycle stability at 120 kV/cm.

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

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

Core‐shell TiO2@Au Nanofibers Derived from a Unique Physical Coating Strategy for Excellent Capacitive Energy Storage Nanocomposites

AbstractPolymer dielectrics have been widely employed in pulsed power systems, but their applications are severely restricted by the low energy density. Incorporating core‐shell nanofillers is one promising strategy to enhance the energy density of polymer dielectrics. Nowadays, core‐shell nanofillers are mainly prepared via chemical coating strategies, which always involve complex chemical synthesis procedures. Herein, a unique physical coating strategy is developed to prepare core‐shell TiO2@Au nanofibers consisting of monodispersed Au nanoparticles homogeneously anchored on the TiO2 nanofibers. Interestingly, the TiO2@Au nanofibers show outstanding dielectric energy storage boosting capability. Specifically, with merely introducing 0.1 wt.% TiO2@Au nanofillers, the TiO2@Au/PVDF composite exhibits a substantially enhanced breakdown strength of 749 MV m−1, which reaches 152.8% of PVDF. Meanwhile, a high dielectric constant of 10.2 (114.1% of PVDF) is obtained. Consequently, an ultrahigh energy density of 18.6 J cm−3, which is 250.1% of PVDF, is achieved. It is further revealed that the significant energy storage boosting effect is originated from the Coulomb blockade and micro‐capacitor effects of the TiO2@Au nanofibers. This work establishes a unique paradigm for the facile preparation of core‐shell nanomaterials, which have huge potential for both dielectric energy storage and other functional nanocomposites.

Fabrication of the low-k films with tunable k value as spacers in advanced CMOS technology

In advanced CMOS technology, a suitable spacer scheme is crucial to alleviate the effects of increasing parasitic resistance and capacitance on device performance as the critical dimensions shrinking. Low dielectric constant (low-k) films, possessing a tunable k value ranging from 3.5 to 6.5, were fabricated using plasma-enhanced atomic layer deposition in a single chamber. The fabrication process involved the deposition of the SiN film via SiH2I2 with N2 plasma, as well as the deposition of the SiOX, SiOCN, and SiON films using diisopropylamino silane with O2, Ar/O2, and N2/O2 plasmas, respectively. The introduction of groups containing carbon (C) tended to loosen the film structure, due to its weak bond strength with Si, thus made distinctions in structural and electrical stability. We developed such a process which can adjust the C-group concentration and O, N content to tune the film k value. The SiOx, SiOCN, SiON, and SiN films had high breakdown strength of 9.04, 7.23, 9.41, and over 11 MV cm−1, and meanwhile low leakage current density of 2.42 × 10−9, 4.78 × 10−8, 1.29 × 10−9, and 9.26 × 10−10 A cm−2, respectively. The films exhibited remarkable thermal stability, enhanced breakdown strength, and suppressed leakage with annealing treatment, which could be attributed to the desorption of —CHX groups. Moreover, the low-k materials demonstrated excellent step coverage both in the inner-spacer cavity and on sidewalls, exploring the potential application as spacers in advanced CMOS structure.