Dielectric Energy Storage Materials Research Articles

Multivariant Me ions design of Bi(Ni0.5Zr0.5)O3 amorphous thin film with high energy storage capability

The development of advanced pulse power technology proposes higher demand for dielectric energy storage materials. However, simultaneously obtaining high polarization and breakdown strength has become an obstacle to the development of dielectric materials. Herein, through the elaborate design of multivariant ions Me, BiMeO3 system thin film Bi(Ni0.5Zr0.5)O3 integrating high polarization, large breakdown strength and a localized heterostructure, generating an excellent energy storage density of 77.42 J cm−3 and efficiency of 70.29% at 5.60 MV cm−1. The enhancive breakdown strength of Bi(Ni0.5Zr0.5)O3 thin film is mainly attributed to the amorphous phase induced by low preparation temperature and the oxygen vacancy bound by the valence change of Ni2+ ion, which reduces leakage current density. This design approach is expected to be widespread for the development of BiMeO3 system thin film.

Superior energy storage performance of < 001 > -oriented NBT-BY-STO relaxor ferroelectric textured ceramics

In this paper, < 001 > -oriented ternary NBT-BY-STO textured ceramics were prepared by tape casting technique based on composition design and orientation engineering strategies. The introduction of BY greatly reduces the grain size and increases the breakdown field strength, resulting in the improvement of the energy storage density. The relaxation behavior and saturation polarization of the ceramics were enhanced by < 001 > -orientation engineering, and so significantly increased energy storage density and energy storage efficiency. Finally, the energy storage performance of NBT-based ceramics was improved obviously. When x = 0.3, the energy storage density reached 5.34 J/cm3, and the energy storage efficiency was 83.91%. The prepared textured ceramics have excellent temperature, frequency stability and charge-discharge characteristics. Therefore, < 001 > -oriented ternary textured ceramics prepared in this paper is a potential dielectric material for pulse powder device, and this strategy of optimizing the energy storage performance also provides guidance of energy storage performance regulation for dielectric energy storage materials.

Overviews of dielectric energy storage materials and methods to improve energy storage density

Overviews of dielectric energy storage materials and methods to improve energy storage density

Achieving ultrahigh energy storage performance in BiFeO3-BaTiO3 based lead free relaxors via a composition optimization strategy

The 0.63(1-x)Bi1.02FeO3-0.37BaTiO3-xBi(Zn2/3(Nb0.85Ta0.15)1/3)O3 (abbreviated BF-BT-xBZNT) high temperature dielectric ceramics were prepared via a two-step sintering (TTS) method. The appropriate medium permittivity achieved in the BF-BT-0.13BZNT ceramic is conducive to mitigating the polarization saturation and improving the breakdown field strength. The domain evolution behavior from piezoresponse force microscopy (PFM) reveals that the introduction of BZNT promotes the formation and switching of more nanodomains of BF-BT ceramics, facilitating the enhancement of energy storage efficiency. The excellent energy storage performance of total energy storage density (Wtot) of 6.06 J/cm3, recoverable energy storage density (Wrec) of 4.85 J/cm3 and a high energy storage efficiency (η) of 80% are simultaneously obtained under 410 kV/cm in the BF-BT-0.13BZNT ceramic. Meanwhile, the ceramic exhibits excellent thermal endurance (10–130 ℃), frequency (1–100 Hz) and fatigue (105 cycles) stability. The current work provides a promising strategy for designing high-performance dielectric energy storage materials which operate in harsh environments.

Enhanced energy storage performance in Sr0.7La0.2Zr0.15Ti0.85O3-modified Bi0.5Na0.5TiO3 ceramics via constructing local phase coexistence

Dielectric capacitors with excellent energy storage performance are highly desirable for electronic industry. Although many excellent studies have been carried out on energy-storage dielectric materials, the explanation of their macroscopic electrical properties from the microscopic point of view remains scarce. In this work, (1-x)Bi0.5Na0.5TiO3-xSr0.7La0.2Zr0.15Ti0.85O3 ((1-x)BNT-xSLZT) relaxor ceramics are designed and fabricated. The recoverable energy density of 5.09 J/cm3 and efficiency of 88% are achieved in 0.67BNT-0.33SLZT ceramic. The ceramic also displays an excellent thermal stability in a wide temperature range (0–200 °C). The good performance of the ceramics is attributed to their heterogeneous structure which contains two different local phases after composition modification. Micro-structure is then validated by the Rietveld refinement and transmission electron microscopy analysis. Moreover, the decrease in domain size and enhancement in domain reversibility are also observed in the sample. The delayed polarization saturation and increased electric field strength significantly enhance the energy storage properties of the ceramics. This work indicates that constructing local phase coexistence is an effective method for obtaining high-performance energy storage ceramics, and may provide a guideline for designing and preparation of dielectric energy storage ceramics with superior properties.

Ultrahigh energy storage density in lead-free antiferroelectric rare-earth-substituted bismuth ferrite

Rare-earth (Re) substitution in BiFeO${}_{3}$ can result in a tuning of the crystal structure from ferroelectric R3c to antiferroelectric Pnma, making (Bi,Re)FeO${}_{3}$ among the best dielectric materials for energy storage. Using a first-principle-based atomistic approach, the authors predict that playing with the Re elements and varying the composition can systematically alter the polarization-versus-electric field (P-E) hysteresis loop of (Bi,Re)FeO${}_{3}$, leading to promising storage performance. For instance, energy density as high as 239 J/cm${}^{3}$ in (Bi,Tm)FeO${}_{3}$ solid solutions and efficiencies being generally beyond 80% are predicted. The influential factors on these energy-storage properties, including transition fields, polarization of the ferroelectric state and dielectric constant, are further discussed based on a simple model.

Excellent energy storage performance of paraelectric Ba0.4Sr0.6TiO3 based ceramics through induction of polar nano-regions

Dielectric energy storage materials with congenitally high power densities and ultrafast discharge rates have been extensively studied for emergent applications. As a typical and traditional dielectric material, paraelectric Ba0.4Sr0.6TiO3 (BST) ceramic exhibits a moderate dielectric constant (εr), low dielectric loss and slightly nonlinear P–E hysteresis. However, its energy storage density (W) is extremely low because of its low maximum polarisation (Pmax) and weak breakdown strength (BDS). In this study, ferroelectric Na0.5Bi0.5TiO3 (NBT) was introduced into paraelectric BST to enhance energy storage performance. The results show that the introduction of NBT induced polar nano-regions (PNRs) in the paraelectric matrix, resulting in a slim hysteresis loop with low remnant polarisation (Pr) and high Pmax simultaneously. Furthermore, owing to a decrease in the oxygen vacancy concentration and an increase in the band gap energy, the BDS of the BST ceramic also significantly increased. As a consequence, a remarkable energy storage density (Wrec = 3.89 J/cm3) and a high energy storage efficiency (η = 83.8%) were realised in the 0.75Ba0.4Sr0.6TiO3-0.25Bi0.5Na0.5TiO3 (0.75BST–0.25NBT) ceramic under a practical electric field of 360 kV/cm. Moreover, the ceramic also exhibited an excellent current density (∼1029.7 A/cm2) and ultrahigh power density (∼128.7 MW/cm2). The attained energy storage performances indicate that the NBT-modified BST ceramics are promising materials for high energy storage capacitor applications field.

Deferred Polarization Saturation Boosting Superior Energy-Storage Efficiency and Density Simultaneously under Moderate Electric Field in Relaxor Ferroelectrics

High-temperature dielectric Bi0.5Na0.5TiO3 (BNT)-based relaxors near a morphotropic phase boundary are developed with excellent energy storage performance. Random distribution of polar nanoregions induced by composition modulation would disrupt the ferroelectric long-range dipolar alignment and weaken the coupling between the ferroelectric domains, yielding slender and deferred polarization–electric field hysteresis loops with relatively high saturation polarization. The reversible nano-domain orientation and growth in relaxors under a delayed electric field result in negligible remnant polarization and advantageous energy storage properties. Simultaneously, superior recoverable energy storage density and efficiency are gained, significantly surpassing the state-of-the-art dielectric energy storage materials under similar moderate electric fields. Vacancies, defect dipole behavior, and structural evolution that relied on an electric field and temperature are discussed to disclose the underlying mechanism associated with phase transition. Even thermal stability and large electrostrictive strain with low hysteresis are achieved in elevated temperatures. These features demonstrate the promising candidates for dielectric energy-storage application and provide a strategy in designing relaxors.

High-temperature polyimide dielectric materials for energy storage: theory, design, preparation and properties

Dielectric capacitors with a high operating temperature applied in electric vehicles, aerospace and underground exploration require dielectric materials with high temperature resistance and high energy density.

Tailoring ferroelectric polarization and relaxation of BNT-based lead-free relaxors for superior energy storage properties

Dielectric energy storage materials have attracted much attention because of their wide applications in the electronics industry. However, low energy storage density and poor thermostability limit their application. In this work, a strategy was proposed to prepare lead-free relaxor ferroelectric ceramics with ultra-high energy storage properties and superior temperature stability by precisely adjusting the relaxation and ferroelectricity states and increasing the electric field intensity. An ultra-high recoverable energy storage density (Wr) of 4.97 J/cm3 and an efficiency (η) of 84.4% are simultaneously obtained for the 0.95(0.9Bi0.5Na0.5TiO3-0.1Ba0.85Ca0.15Zr0.1Ti0.9O3)-0.05BaSnO3 ceramic. Moreover, a high Wr of 2.73 J/cm3 with brilliant η of 80.6% are obtained in the ceramic at 140 ℃ and there is almost no thermal degradation of energy storage properties from 25 ℃ to 140 ℃. The Wr and η have decreased by 2.2% and 1.9% after 105 cycles under 200 kV/cm, respectively, which demonstrates the good cycle stability of the sample. A discharge power density of up to 99.0 MW/cm3 is obtained in the 0.95(0.9Bi0.5Na0.5TiO3-0.1Ba0.85Ca0.15Zr0.1Ti0.9O3)-0.05BaSnO3 ceramic and the good charge and discharge performance of this sample is important for practical applications.

Asymmetric Trilayer All‐Polymer Dielectric Composites with Simultaneous High Efficiency and High Energy Density: A Novel Design Targeting Advanced Energy Storage Capacitors

AbstractPolymeric dielectrics have attracted intensive attention worldwide because of their huge potential for advanced energy storage capacitors. Thus far, various effective strategies have been developed to improve the inherent low energy densities of polymer dielectrics. However, enhanced energy density is always accompanied by suppressed discharge efficiency, which is detrimental to practical applications and deserves considerable concern. Targeting at achieving simultaneous high energy density and high discharge efficiency, the unique design of asymmetric all‐polymer trilayer composite consisting of a transition layer sandwiched by a linear dielectric layer and a nonlinear dielectric layer is herein reported. It is demonstrated that the nonlinear dielectric layer offers high energy density, while the linear dielectric layer provides high discharge efficiency. Especially, the transition layer can effectively homogenize the electric field distribution, resulting in greatly elevated breakdown strength and improved energy density. In particular, a high efficiency of 89.9% along with a high energy density of 12.15 J cm−3 are concurrently obtained. The asymmetric trilayer all‐polymer design strategy represents a new way to achieve high‐performance dielectric energy storage materials.

Domain Engineered Lead-Free Ceramics with Large Energy Storage Density and Ultra-High Efficiency under Low Electric Fields.

Dielectric energy storage materials are becoming increasingly popular due to their potential superiority, for example, excellent pulse performance as well as good fatigue resistance. Although numerous studies have focused on lead-free dielectric materials which possess outstanding energy storage characteristics, the results are still not satisfying in terms of achieving both large discharging energy density (Wd) and high discharging efficiency (η) under low electric fields, which is crucial to be conducted in miniatured electronic components. Here, we adopt the strategy of domain engineering to develop sodium bismuth titanate (Bi0.5Na0.5TiO3)-based ceramics employed in the low-field situation. Remarkably, a large Wd of 2.86 J/cm3 and an ultrahigh η of 90.3% are concurrently obtained in 0.94(Bi0.5Na0.5)0.65(Ba0.3Sr0.7)0.35TiO3-0.06 Bi(Zn2/3Nb1/3)O3 system when the electric field is as low as 180 kV/cm. Additionally, the ceramic shows brilliant thermal endurance (20-160 °C) and frequency stability (0.1-100 Hz) with high Wd (>1.48 J/cm3) together with an ultra-high η (>90%). What's more, the ceramic displays a fast charge-discharge time (t0.9 = 109.2 ns). The piezoresponse force microscopy (PFM) results reveal that the introduced Bi(Zn2/3Nb1/3)O3 disrupts the microdomains of (Bi0.5Na0.5)0.65(Ba0.3Sr0.7)0.35TiO3 ceramics and promotes the formation of nanodomains, leading to enhanced energy storage properties. The current work may arouse interest in developing low-field high-performing dielectric capacitors for energy storage application.

Bimetallic organic framework NiFeMOF driven by tiny Ag particles for PVDF dielectric composites

Two-dimensional (2D) anisotropic ferroelectric nanoparticles are considered as potential candidates in polymer-based dielectric energy storage materials. We successfully synthesized a new class of Ag@NiFeMOF 2D ferroelectric hybrid nanoplates and added it to PVDF matrix to prepare Ag@NiFeMOF/PVDF composites (MOF = metal-organic framework). The morphology of composites reveals that Ag atoms are uniformly dispersed in the nanoplates as 14 nm clusters. The discharge energy storage density of composites shows a remarkable improvement of over 610% compared to the pure PVDF sample and reaches a value of 8.01 J/cm3 (η = 64%). We hypothesize that the bimetallic NiFeMOF exhibits a stronger electric dipole moment than the monometallic NiMOF under the strengthening effect of Ag particles, which improves the polarization ability of composites. In addition, under high electric field strength, the Ag-induced Coulomb blocking effect in NiFeMOF nanoplates inhibits the migration of electrons, improves the electric field breakdown strength, and thereby increases the energy storage ability of the composites.

Simultaneously achieved high‐energy storage density and efficiency in (K,Na)NbO3‐based lead‐free ferroelectric films

AbstractWith the development of advanced electrical and electronic devices and the requirement of environmental protection, lead‐free dielectric capacitors with excellent energy storage performance have aroused great attention. However, it is a great challenge to achieve both large energy storage density and high efficiency simultaneously in dielectric capacitors. This work investigates the energy storage performance of sol‐gel‐processed (K,Na)NbO3‐based lead‐free ferroelectric films on silicon substrates with compositions of 0.95(K0.49Na0.49Li0.02)(Nb0.8Ta0.2)O3‐0.05CaZrO3‐xmol% Mn (KNN‐LT‐CZ5‐xmol% Mn). The appropriate amount of Mn‐doping facilitates the coexistence of orthorhombic and tetragonal phases, suppresses the leakage current, and considerably enhances the breakdown strengths of KNN‐LT‐CZ5 films. Consequently, large recoverable energy storage density up to 64.6 J cm−3with a high efficiency of 84.6% under an electric field of 3080 kV cm−1are achieved in KNN‐LT‐CZ5‐5 mol% Mn film. This, to the best of our knowledge, is superior to the majority of both the lead‐based and lead‐free films on silicon substrates and thus demonstrates great potentials of (K,Na)NbO3‐based lead‐free films as dielectric energy storage materials.

Improved energy storage performance of Ba0.4Sr0.6TiO3 by doping high polarization BiFeO3

Dielectric energy storage materials have a high power density, which has attracted much attention in many fields, such as pulsed power generation and electric vehicles etc. As a typical and traditional energy storage material, barium strontium titanate (Ba1-xSrxTiO3) has been widely used in this field. However, its energy storage density is extremely low. In this work, (1-x)Ba0.4Sr0.6TiO3-xBiFeO3 ceramics (x = 0.05, 0.10, 0.25) were prepared by the traditional solid-state method. The results show that the energy storage density of the 0.90Ba0.4Sr0.6TiO3-0.10BiFeO3 ceramic with average grain size of 1.5 μm is 3.1 J/cm3, and the efficiency is 74.1% at a low electric field of 240 kV/cm. In addition, the energy storage density of the 0.95Ba0.4Sr0.6TiO3-0.05BiFeO3 ceramic can be as high as 3.29 J/cm3. The energy storage efficiency can reach 90.69% in the electric field of 300 kV/cm. It can be concluded that the addition of BiFeO3 can greatly enhance the energy storage property of Ba0.4Sr0.6TiO3, which indicates that Ba1-xSrxTiO3 ceramics with BiFeO3 will be good candidates in the field of power electronics.

Enhancement of dielectric breakdown strength and energy storage of all-polymer films by surface flattening

All-organic dielectric films with the significant advantage of easy processing are highly desired in electronic and electric industry. As dielectric energy storage materials, improvement of their dielectric permittivity and electric breakdown strength is a long-standing work. Polytetrafluoroethylene (PTFE) films possess excellent high temperature properties but their electric breakdown strength is largely dependent on the surface flattness. Especially, interconnecting fiber structure tends to form during calcination when an ultrathin film is fabricated through a coating process. Herein, the surface of the PTFE films was flattened with epoxy resin. A high electric breakdown strength of 555 kV/mm, which is 134% of the pure PTFE film, and an improved dielectric permittivity of 2.3 have been achieved for the PTFE film immersed in 0.5 wt% epoxy solution at room temperature. It displays a discharged energy density of 3.58 J/cm3 (2.2 times of the pure PTFE film) with 98% discharge efficiency. The achieved high electric breakdown strength is owing to the reduced local electric field at the interface between film surface and electrode according to the simulation results. Besides, it also achieved a high discharged energy density of 1.93 J/ cm3 at 150 °C with 99% efficiency. Therefore, using organic to flatten the surface of polymer films has proved significantly effective in improving the dielectric energy storage performance.

High recoverable energy storage density and large energy efficiency simultaneously achieved in BaTiO3–Bi(Zn1/2Zr1/2)O3 relaxor ferroelectrics

Relaxor ferroelectrics have attracted much attention as electric energy storage materials for intermittent energy storage because of their high saturated polarization, near-zero remnant polarizations, and considerable dielectric breakdown strength (BDS). Despite the numerous efforts, the dielectric energy storage performance of relaxor ferroelectric ceramics is incomplete or unsatisfactory. The enhancement of recoverable energy storage density Wrec usually accompanies with the sacrifice of discharge-to-charge energy efficiency η; therefore, it is an important issue to achieve high recoverable Wrec and large efficiency η simultaneously. In this work, the (1-x)BaTiO3-xBi(Zn1/2Zr1/2)O3 (abbreviated as BT-100xBZZ, 0 ≤ x ≤ 0.20) ferroelectric ceramics were prepared using the conventional solid-state reaction method. The phase structure, microstructural morphology, dielectric and ferroelectric properties, relaxation behaviors, and energy storage properties of BT-BZZ ceramics were investigated in detail. X-ray powder diffraction, dielectric spectra, and ferroelectric properties confirm the transformation of tetragonal phase for normal ferroelectrics (BT) to pseudo-cubic phase for relaxor ferroelectrics (BT-8BZZ). A high recoverable energy storage density Wrec of 2.47 J/cm3 and a large energy efficiency η of 94.4% are simultaneously achieved in the composition of BT-12BZZ, which presents typical weakly coupled relaxor ferroelectric characteristics, with an activation energy Ea of 0.21 eV and a freezing temperature Tf of 139.7 K. Such excellent energy storage performance suggests that relaxor ferroelectric BT-12BZZ ceramics are promising dielectric energy storage materials for high-power pulsed capacitors.

Enhanced energy storage performance of nanocomposites filled with paraelectric ceramic nanoparticles by weakening the electric field distortion

Polymer-based dielectric nanocomposites, which combines the high dielectric constant of ceramic materials and the high breakdown strength of polymer materials, has emerged as one of the most effective progress for the advanced dielectric energy storage materials. To improve energy storage performance, the core-shell structured SiO2@SrTiO3 paraelectric nanoparticles are used as fillers in constructing the polymer-based nanocomposites. Hence, this paper systematically investigates the impacts of filler content on energy storage performance and breakdown strength, and provides insight into the polarization behavior of different composites filled with paraelectric and ferroelectric nanoparticles (SiO2@BaTiO3), respectively. Combined finite element simulations, it is shown that the dielectric constant of the paraelectric ceramic is more similar to the polymer matrix, resulting in weakening the electric field distortion in the dielectric. Furthermore, due to the paraelectric characteristics of SrTiO3 nanoparticles and the diminution of interface polarization, the remnant polarization of the nanocomposites can be significantly reduced. The polymer-based dielectric nanocomposites exhibit more impressive energy storage, of 11.42 J/cm3 at 350 MV/m with 2.5 vol% paraelectric SiO2@SrTiO3 nanoparticles, which is superior to the composite filled with ferroelectric nanoparticles. Overall, this finding not only establishes a new direction for the structural design of fillers but also provides insight into an underlying mechanism to control interface polarization in the dielectric composites.

Energy storage performance in polymer dielectrics by introducing 2D SrBi4Ti4O15 nanosheets

Polymer-based dielectric energy storage materials have been playing critical roles in high-performance energy storage capacitors due to their high breakdown electric fields and facile processability. However, the low energy density and efficiency of polymer-based film capacitors limit their widespread application in various electronics products. In this contribution, we synthesized the SrBi4Ti4O15 (SBT) nanosheets with large aspect ratio by using the molten salt method and introduced them into the PVDF matrix to prepare a multilayer nanocomposite film, of which the discharge energy density and discharge efficiency were much improved. Finite element simulation results show that the addition of 2D SBT nanosheets can significantly improve the local electric field distribution of nanocomposite films. Finally, a high discharge energy density of 11.69 J cm−3 and an excellent discharge efficiency of 78.95% were simultaneously achieved in the 0/5/0 sample. This work provides a reference for polymer-based dielectrics with excellent comprehensive energy storage performance.

Rational Design of Soluble Polyaramid for High‐Efficiency Energy Storage Dielectric Materials at Elevated Temperatures

AbstractHigh‐temperature polymer dielectrics are in great demand for harsh‐environment applications. Maintaining high‐energy storage density and low loss at elevated temperatures remains a major challenge for polymer dielectrics. In this work, a new type of polymer dielectric material is designed, which exhibits comparable dielectric properties in the start‐of‐the‐art dielectric nanocomposites and a superior potential for scale up. A soluble, glassy state polymer with a polarizing group is designed by introducing a weakly polar group into the polyaramid (PA) backbone to dilute the hydrogen bonding of the PA parent species. This increases the mobility of the molecular dipole within the polymer in the glassy state, thereby increasing its dielectric constant while maintaining the high‐temperature performance. The result of this design is a polymer with a glass transition temperature of 251 °C, a dielectric constant of up to 4.5, and a dielectric loss of 1%, while maintaining 2.1 J cm−3 energy density and 86.8% efficiency at 200 °C. This polymer, with its excellent, intrinsic, electrical‐energy‐storage properties can also be adapted for a roll‐to‐roll capacitor film production. Breaking intermolecular hydrogen bonds to enhance the electrical‐energy‐storage properties of polymers is an excellent path for designing polymer dielectrics with high‐temperature capabilities.