Recoverable Energy Research Articles

Modified Si3N4 filler enhancing the energy storage performance and thermal stability of a P(VDF‐HFP) based composite

AbstractTo improve the high‐temperature stability of poly(vinylidene fluoride hexafluoropropylene) P(VDF‐HFP)‐based composite film for its potential application in energy storage, the modified silicon nitride (mSi3N4) nanoparticles are fabricated using silane coupling agent (KH‐570) and introduced into P(VDF‐HFP). When the mass fraction of mSi3N4 is 7.5 wt%, the recoverable energy density (Wrec) of the mSi3N4/ P(VDF‐HFP) composite film reaches to 1.79 J/cm3 under a 125 MV/m electric field, which is 82.7% higher than pure P(VDF‐HFP). Interestingly, the dielectric properties of mSi3N4/P(VDF‐HFP) show a considerable thermal stability at a high‐frequency ranging from −20 to 160°C, providing an effective approach for preparing energy storage composites working for high‐temperature environments.

Achieving an appropriate polarization-breakdown synergy of multilayer films for dielectric energy storage through temperature gradient annealing

Large polarization and high breakdown strength are the key to achieving an idea energy storage density in dielectric capacitors, but unfortunately the trade-off problem between them is difficult to evade, particularly for those dielectrics with different crystalline degrees. Herein, we propose an appropriate polarization-breakdown synergistic strategy of dielectric multilayer films through temperature gradient annealing. The dielectric properties of a serials of (Pb, La)(Zr, Ti)O3/SrTiO3/(Pb, La)(Zr, Ti)O3 (PLZT/STO/PLZT) structures with different annealing temperature for each layer are compared. The optimum recoverable energy density of 57.9 J/cm3 is achieved at a high breakdown electric field of 5.78 MV/cm and a moderate maximum polarization of 22.5 μC/cm2. In addition to the role of suppressing the carriers transport of interlayer STO, the balance between polarization and breakdown strength in bottom and top PLZT layers with individual dielectric characteristics should be responsible for the enhanced energy storage performance (ESP). The results suggest that it is a feasible way to optimize the ESP of dielectric multilayer films through designing different stacking layer via temperature gradient annealing heat treatment.

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

Enhanced low-field energy storage performance and dielectric stability in (Bi0.4Sr0.2K0.2Na0.2)(Ti1-xZrx)O3 high-entropy ceramics via B-site modification

The current global energy situation is tense, necessitating the development of high-efficiency, low-cost, and eco-friendly energy materials. In this study, a series of perovskite lead-free relaxor ferroelectric ceramics, denoted as (Bi0.4Sr0.2K0.2Na0.2)(Ti1-xZrx)O3 (BSKNT-xZr) were designed to enhance the storage performance. The findings indicate that all samples exhibit a single perovskite structure. As the Zr4+ content increases, the configurational entropy of the samples increases, the cell volume expands, and the hysteresis loops become finer, while maintaining a high maximum polarization (Pm) and effectively enhancing the energy storage performance. For the ceramic with x = 0.10, the energy density (Wtot), recoverable energy density (Wrec), and energy storage efficiency (η) values were determined to be 3.16 J/cm3, 2.67 J/cm3, and 84.3%, respectively, under an electric field of 230 kV/cm. Moreover, the introduction of Zr4+ reduces the relative permittivity and broadens the temperature range (ΔT) that simultaneously satisfies Δε/ε150°C ≤ ±15% and 0 ≤ tanδ ≤ 0.02. This investigation underscores the potential of BSKNT-xZr ceramics as high-performance, cost-effective, and environmentally friendly energy materials for addressing global energy requirements.

A Broad-High Temperature Ceramic Capacitor with Local Polymorphic Heterogeneous Structures.

Crafting high-performance dielectrics tailored for pulsed power capacitors, in response to the escalating demands of practical applications, presents a formidable challenge. Herein, this work introduces a novel lineup of lead-free ceramics with local polymorphic heterogeneous structures, defined by the formula (1-x)[0.92BaTiO3-0.08Sr(Mg1/2Ti3/4)O3]-x(Na0.5Bi0.5)TiO3 (BT-SMT-xNBT). This innovative multi-scale synergistic strategy, spanning from the atomic to grain scale, yields materials with a giant recoverable energy density (Wrec) of 10.1 J·cm-3 and an impressive energy efficiency (η) of 95.0%. The integration of linear end elements SMT can significantly mitigate the polarization hysteresis while concurrently boosting the breakdown strength, thus enhancing overall energy efficiency. Furthermore, the inclusion of NBT with high polarization serves to amplify domain size, thereby reinforcing the electric field-induced polarization. This addition also stimulates the creation of polymorphic heterostructures, where tetragonal and rhombohedral nanodomains coexist, as validated by aberration-corrected transmission electron microscopy. Notably, the BT-SMT-0.2NBT ceramics have demonstrated outstanding high-temperature energy storage capabilities, with a Wrec of 7.2 J·cm-3 and an η of 92.2% at 150 °C, along with remarkable broad-temperature stability (ΔWrec, Δη ≤ 4.0%, ≈20-150 °C). These achievements in this work propel the field toward more practical and durable solutions of energy storage dielectrics.

Superior energy storage performance in NaNbO3‐based lead‐free ceramics under low electric field

AbstractNaNbO3 (NN)‐based materials have attracted widespread attention due to their advanced energy storage performance and eco‐friendliness. However, achieving high recoverable energy storage densities (Wrec) and efficiency (η) typically requires ultrahigh electric fields (E > 300 kV/cm), which can limit practical use. In this work, we present a synergistic strategy that employs the ferroelectric material Bi0.5Na0.5TiO3 (BNT) to augment the Pmax and the linear material Bi0.2Sr0.7TiO3 (BST) to optimize the P–E loops. Furthermore, a two‐step sintering process is implemented to preserve high Pmax values under lower electric field. As a result, ternary (1−x)(0.90NN‐0.10BNT)‐xBST was successfully prepared, achieving a high Wrec of 5.1 J/cm3 and a η of 85% in x = 0.20 samples at a low electric field of 290 kV/cm. Moreover, the x = 0.20 samples showed good frequency stability (1–200 Hz) and temperature stability (27°C–100°C). These results provide guidance for the development of ceramics with high energy storage properties under low electric fields.

Synthesis, characterization, and electrical properties of Nd3+‐doped (Bi0.4Na0.2K0.2Ba0.2)TiO3 high‐entropy ceramics

AbstractRecently, high‐entropy perovskites have attracted considerable attention due to their diverse chemical composition and multifunctionality. In this study, the high‐entropy approach was employed in a (Bi0.4Na0.2K0.2Ba0.2)TiO3 matrix, and Nd3+ was introduced to enhance the configurational entropy and modify its dielectric and ferroelectric properties. Notably, despite Nd3+ doping, all samples maintained a tetragonal perovskite structure at room temperature. The configurational entropy increased with the Nd3+ concentration, consequently leading to a gradual decline in the ferroelectric properties along with the associated temperature (Tm) and maximum dielectric constant (εm). The P–E loops of the ceramics also became thinner as Pm and Pr decreased, resulting in a slow decrease in the recoverable energy density (Wrec) and a simultaneous increase in the energy storage efficiency (η). Especially, the energy storage performance reached its peak at an Nd3+ concentration of 12 mol%, exhibiting an energy storage efficiency of 85.8% and a recoverable energy storage density of 0.74 J/cm3 at a low electric field of 100 kV/cm. These results highlight the potential of this material for dielectric applications in low electric fields and contribute to the advancement of alternative high‐entropy energy storage perovskite ceramics.

Investigating structural, dielectric and energy storage properties of NaNbO3 based ferroelectric ceramics

Sodium niobate (NaNbO3) based dielectric materials are getting recognition for the electric energy storage applications due to their promising ferroelectric/anti-ferroelectric properties. In the present work, (0.95-x)NaNbO3-0.05SrTiO3-xBi(Fe1/3Zn1/3Ti1/3)O3 (abbreviated as NNSTBFZT, x=0.04, 0.07 and 0.10) lead-free ferroelectric ceramics were synthesized using conventional solid-state reaction technique. A magnificent recoverable energy storage density (Wrec) and an ultrahigh energy storage efficiency (η) have been observed for x4 (∼1.05 J/cm3) and x10 (∼85 %) samples, respectively which reliant on the non-equivalent replacement of ions at the A and B sites of perovskite unit cell. Further, the phase investigation has been studied using X ray diffraction and Raman spectroscopy, which elucidate the effect of incorporation of the substituent ions at host matrix properly. A moderate dielectric constant with ultralow losses has been obtained and all the samples show diffuse phase transition, which is in favor of enhanced energy storage parameters. Moreover, the morphological analysis indicates decrease in grain size ∼ 1 µm, which also reflects the increased breakdown strength responsible for enhancing energy storage capacity. Therefore, proposed sodium niobate based ceramics become favorable for high energy dielectric capacitors applications.

The SrBi4Ti4O15-based sandwich-structured films for energy storage capacitors

Both large spontaneous polarization and high breakdown strength are necessary to achieve high recoverable energy density in capacitors. Unfortunately, there is a trade-off between them within the homogeneous medium. Therefore, a sandwich structure with a high polarization layer was designed in the Aurivillius phase lead-free film to address this issue. This strategy can effectively enhance the polarization capability by introducing a highly spontaneous polarization layer and also improve the breakdown strength by reducing the leakage current caused by interfacial barriers and grain refinement. Benefiting from the synergistic effects, a high energy density of 50.4 J/cm3 with a high efficiency of 76.6% in the sandwich-structure thin film capacitors were achieved. In addition, the energy storage performance exhibits good wide frequency range and high-temperature stability. This approach is generally applicable to the design of other ferroelectrics and dielectrics promises high-performance energy storage capacitors.

Improving the Energy Storage Performance in Bi0.5Na0.5TiO3-Based Ceramics by Combining Relaxor and Antiferroelectric Properties.

Ceramic capacitors have received great attention for use in pulse power systems owing to their ultra-fast charge-discharge rate, good temperature stability, and excellent fatigue resistance. However, the low energy storage density and low breakdown strength (BDS) of ceramic capacitors limit the practical applications of energy storage technologies. In this work, we present a series of relaxor ferroelectric ceramics (1-x) [0.94 Bi0.5Na0.5TiO3 -0.06BaTiO3]- x Sr0.7Bi0.2TiO3 (1-x BNT-BT- x SBT; x = 0, 0.20, 0.225, 0.25, 0.275 and 0.30) with improved energy storage performances by combining relaxor and antiferroelectric properties. XRD, Raman spectra, and SEM characterizations of BNT-BT-SBT ceramics revealed a rhombohedral-tetragonal phase, highly dynamic polar nanoregions, and a reduction in grain size with a homogeneous and dense microstructure, respectively. A high dielectric constant of 1654 at 1 kHz and low remnant polarization of 1.39 µC/cm2 were obtained with the addition of SBT for x = 0.275; these are beneficial for improving energy storage performance. The diffuse phase transition of these ceramics displays relaxor behavior, which is improved with SBT and confirmed by modified the Curie-Weiss law. The combining relaxor and antiferroelectric properties with fine grain size by the incorporation of SBT enables an enhanced maximum polarization of a minimized P-E loop, leading to an improved BDS. As a result, a high recoverable energy density Wrec of 1.02 J/cm3 and a high energy efficiency η of 75.98% at 89 kV/cm were achieved for an optimum composition of 0.725 [0.94BNT-0.06BT]-0.275 SBT. These results demonstrate that BNT-based relaxor ferroelectric ceramics are good candidates for next-generation ceramic capacitors and offer a potential strategy for exploiting novel high-performance ceramic materials.

An Intragranular Segregation Structure Enables an Excellent Energy Storage Performance in Composite Dielectrics through Delayed Saturation Polarization.

An electrostatic capacitor for energy storage is an important basic component of pulse power electronics. The electrical breakdown strength (Eb) of normal ferroelectrics is low, which limits their application in dielectric energy storage. Constructing a 0-3-type composite dielectric, that is, introducing an insulating metallic oxide into the ferroelectric matrix, can greatly enhance Eb. Unfortunately, an intergranular secondary phase typically forms that causes large attenuation of the dielectric constant, which leads to limited improvement of energy storage performance. In this work, a composite ceramic with an intragranular segregation structure was intentionally designed using the BaTiO3-BaZrO3-CaTiO3 (BCZT) system as an example. Compared with those of a BCZT solid solution without a secondary phase and a BCZT composite with a grain-boundary secondary phase, the rationally designed BCZT composite with an intragranular secondary phase delivered a large recoverable energy density of 5.86 J/cm3 and high efficiency of 86.7% at a moderate electric field of 550 kV/cm. Such performance was achieved because the intragranular segregation structure displayed delayed saturation polarization with a high Eb. This microstructural engineering strategy is generally applicable to optimize composite dielectrics to meet the demands of high-performance energy storage capacitors.

Combinatorial Optimization of Grain Size and Domain Morphology Boosts the Energy Storage Performance in (Bi0.5Na0.5)TiO3-Based Dielectric Ceramics.

Lead-free dielectric ceramics exhibiting excellent energy storage capacity, long service life, and good safety have been considered to have immense prospects in next-generation pulsed power capacitors. However, it is still challenging to simultaneously achieve large recoverable energy density (Wrec), high efficiency (η), and excellent charge-discharge performance. Herein, we fabricated lead-free (1 - x)(Bi0.5Na0.5)TiO3-x(Sr0.7Bi0.1La0.1)TiO3 ((1 - x)BNT-xSBLT) dielectric ceramics, and a good balance between Wrec ∼ 4.15 J/cm3 and η ∼ 93.89% under 333 kV/cm, as well as superior charge-discharge properties (power density PD ∼ 185.42 MW/cm3, discharge energy density Wd ∼ 2.2 J/cm3, and discharge time t0.9 ∼ 53.8 ns under 250 kV/cm), was achieved in 0.6BNT-0.4SBLT ceramics. The good energy storage performance can be attributed to the synergistic contributions of significantly enhanced Eb caused by grain refinement and the large ΔP values induced by polar nanoregions (PNRs) under a high external electric field. Moreover, the 0.6BNT-0.4SBLT ceramics also present excellent temperature stability of energy storage properties (the variations of Wrec and η less than 0.45% and 0.14%, respectively) over a temperature range of 25-185 °C. These figures of merit make 0.6BNT-0.4SBLT ceramics the most promising candidate for energy storage capacitors in advanced pulse power systems.

Enhanced energy storage performance of tungsten bronze structured BaNb2O6-modified (Bi0.5Na0.5)TiO3 ceramics

The rapid development of the electronic devices and increasing attention to environmental problems have put forward a huge demand for high-performance lead-free dielectric energy storage ceramics. In this work, tungsten bronze structured BaNb2O6 (BN) modified perovskite structured (Bi0.5Na0.5)TiO3 (BNT) ceramics, BNT-xBN (0 <x< 0.15), were prepared to optimize the energy storage performance of BNT. The results show that the lattice distortion and dielectric relaxation behavior of BNT ceramic can be induced by BN addition. Meanwhile, the introduction of tungsten bronze structured BN results in the grain refinement and the increasing of resistivity, thereby significantly enhancing the electrical breakdown strength (Eb). Accordingly, the BNT-0.1BN ceramic displays good energy storage performance with high recoverable energy density (Wrec ∼ 3.41 J/cm3) at an great Eb of 358 kV/cm, accompanied by the wide temperature stability at 30–150 °C (Wrec varies within ±12.8 %, efficiency (η) varies within ±6.7 %). The enhanced energy storage performance demonstrates that introducing tungsten bronze structure is a feasible method to prepare high-performance perovskite energy storage ceramics.

Optimized energy storage performances via high-entropy design in KNN-based relaxor ferroelectric ceramics

Dielectric capacitors play an irreplaceable role in complex and integrated electronic systems. However, attaining ultrahigh recoverable energy storage density (Wrec) alongside energy storage efficiency (η) poses a formidable challenge, impeding the advance towards the miniaturization and integration of cutting-edge energy storage devices. In this work, a high-entropy strategy with a viscous polymer process is adopted, bringing about ultrafine grains and polar nanoregions (PNRs) accompanied by enhanced electrical homogeneity and polarization relaxation characteristics. As a result, an ultrahigh Wrec ∼ 7.51 J/cm3 is achieved in a high-entropy KNN-based energy storage ceramic with a high η ∼ 88.4% at 750 kV/cm. Moreover, the ceramic capacitor exhibits a colossal power density reaching approximately 420 MW/cm3 and a discharge energy density of approximately 4.85 J/cm3 at 160 ℃. Impressively, it maintains low variation rates of less than 4% across a broad temperature range from 20 ℃ to 160 ℃. The new approach opens avenues for the design and development of superior dielectric materials used in next-generation high-power pulse devices.

High energy storage performance in SrZrO3-modified quaternary relaxor ferroelectric ceramics

Lead-free relaxor ferroelectric ceramics have attracted much attention in pulse power systems owing to their excellent energy storage performance and environmentally friendly characteristics. However, it is challenging to simultaneously achieve high energy storage density and efficiency in ferroelectric ceramics for practical applications. Herein, a novel optimization strategy is designed by introducing a linear dielectric SrZrO3 (SZ) with wide bandgap (Eg) into the BaTiO3-Bi0.5Na0.5TiO3-NaNbO3 (BT-BNT-NN) to form quaternary ceramics, disrupting long-range ferroelectric ordering and constructing weakly coupled polar nanoregions (PNRs). As a result, the recoverable energy density (Wrec) and energy storage efficiency (η) are simultaneously improved in (1-x) (BT-BNT-NN)-xSZ ceramics. At an electric field of 530 kV/cm, a Wrec of 3.37 J/cm3 and an η of 82.5 % were optimally achieved at x = 0.16 due to the formation of slim P-E loops, delayed polarization saturation, and ultra-high breakdown field strength (Eb), where the improvement of Eb is attributed to the reduction of porosity and the increase of Eg. Furthermore, the as-fabricated samples also exhibit excellent frequency and temperature stability. This study provides an effective method for developing high-performance dielectric capacitors for energy storage applications.

Multiferroic properties and local ferroelectricity of polycrystalline LuFeO3 thin films with triangular grains on glass substrates

Polycrystalline LuFeO3 (LFO) thin films were prepared on multilayer Pt/Ta/glass substrates. The ferroelectric hysteresis loop of the LFO thin film exhibited a remanent polarization of about 5.7 μC/cm2. The ferroelectric hysteresis loop of the LFO thin film deposited at a relatively slow rate provides valuable information about its recoverable energy density (8.8 J/cm3) and loss energy density (9.3 J/cm3), resulting in an estimated energy storage efficiency of around 49%. The LFO thin film had triangular grains with a diameter of approximately 90 nm, which well reflects the crystallinity of hexagonal LFO. From the local piezoelectric d33 hysteresis loops of a triangular grain, it was confirmed that the edge of a triangular grain had a remanent d33 value larger than the center of a triangular grain. Additionally, a mosaic domain structure of the LFO thin film was well correlated with the AFM image. By applying the Landau, Lifshitz, and Kittel (LLK) scaling law, it was confirmed that the LFO thin films have a domain wall energy lower than that of PbTiO3 thin films.

High energy density and energy efficiency in AgNbO3-based multilayer ceramic capacitors induced by coexisted antiferroelectric and paraelectric phases

AgNbO3-based lead-free antiferroelectric materials have been attracted increasing attention due to their excellent energy storage performance. But most of the AgNbO3-based ceramics still suffer from low energy efficiency. Herein, coexisted antiferroelectric phase and paraelectric phase are realized in La-doped AgNbO3-based multilayer ceramic capacitors at room temperature, which resulted in slim polarization-electric field loops with hysteresis-free and high breakdown strength over 1000 kV/cm. Both the hysteresis-free polarization-electric field loops and high breakdown strength are beneficial for the energy storage density and energy efficiency. In (Ag0.64La0.12)NbO3 multilayer ceramic capacitors, a high breakdown strength of 1060 kV/cm was attained, which contributes to a recoverable energy storage density (Wrec) of 9.1 J/cm3 and an energy efficiency (η) of 95.8%. Furthermore, the Wrec and η remains above 7.5 J/cm3 and above 83% in the temperature range of 30 °C to 130 °C under 1000 kV/cm, and remains above 4.8 J/cm3 and above 91% in the frequency range of 1 to 100 Hz under 700 kV/cm. This work provides a feasible method for preparing AgNbO3-based ceramics with high energy storage performance.

Enhanced low‐field energy storage performance in Nd3+‐doped (Bi0.40K0.2Na0.2Sr0.2)TiO3 high‐entropy ceramics

AbstractThe burgeoning requirement for compact electronic devices has intensified research into lead‐free dielectric ceramics that offer superior recoverable energy storage density and efficiency at low electric fields. In this study, we report the synthesis of Nd3+‐doped (Bi0.4K0.2Na0.2Sr0.2)TiO3 perovskite ceramics via the solid‐state reaction technique. The synthesized ceramics adopted a tetragonal crystal structure. As the concentration of Nd3+ ions increased, both the maximum dielectric constant (εm) and its corresponding temperature (Tm) decrease. The incorporation of Nd3+ ions perturbed the long‐range ferroelectric order, leading to diminished maximum polarization (Pm) and remanent polarization (Pr). The ceramics achieved optimal properties with 12 mol% Nd3+ doping, showcasing a significant recoverable energy storage density of 1.50 J/cm3 at a low electric field of 140 kV/cm, along with an exceptional storage efficiency of 94.6%. This research not only highlights a promising candidate for dielectric materials in low electric field applications but also introduces an innovative approach to enhance energy storage performance.

Achieving high energy storage density and charge-discharge performance via high-energy ball milling combined with two-step sintering

In this study, the microstructure, ferroelectricity, energy storage density, and charge-discharge characteristics of 0.95(K0.5Na0.5)NbO3-0.05Ba(Zn1/3Nb2/3) (0.95KNN-0.05BZN) ceramic, fabricated by combining two-step sintering with high-energy ball milling, were investigated. The two-step sintering technique enabled a wide sintering temperature range of 1020–1120 °C for the ceramic. Accordingly, under optimal sintering conditions, the ceramic exhibited high relative density (98.1 %) and nanoscale grain size (<90 nm). The samples also displayed excellent pulse power performance at room temperature with a high recoverable energy storage density (Wrec) of 3.1 J/cm3, along with the following charge-discharge parameters: current density (CD), power density (PD), and discharge time (t0.9) reached 1821.7 cm−3, 227.7 MW/cm3, and 36.8 ns, respectively. The ceramic also obtained robust frequency stability (10–1000 Hz), good temperature stability (30–130 °C), and outstanding fatigue resistance (105 cycles), indicating its potential application in improved pulse capacitor materials.

High-performance electric energy storage in BiFeO3–Ba(Ti0.8Zr0.2)O3 relaxor ferroelectric ceramics

Perovskite relaxor ferroelectrics have been widely developed for energy storage applications due to their exceptional dielectric properties. This work explores the energy storage performance, thermal stability, and structural evolution in (1-x)BiFeO3–x Ba(Ti0.8Zr0.2)O3 ceramics (x = 0.3, 0.4, 0.5, and 0.6) via modulating Ba(Ti0.8Zr0.2)O3 (BZT) concentration. An enhancement of breakdown electric field from 120 kV/cm at x = 0.3–220 kV/cm at x = 0.5 can be attributed to increased grain boundaries and nanodomains as electric barriers to inhibit charge mobility. A high recoverable energy density of 5.9 J/cm3 and a high energy efficiency of 86.2 % were achieved at x = 0.5 and 0.6, respectively. The structure shifts from ferroelectric rhombohedral R3c symmetry toward a coexistence of nonpolar symmetries (including tetragonal P4/mmm, cubic Pm-3m, and orthorhombic Pbnm) with increasing BZT. The integration of BZT in BiFeO3 demonstrates to break the long-range order and promote the formation of polar nanoregions and nanodomains, leading to a high-efficiency energy storage.