Enhanced energy storage property achieved in Na0.5Bi0.5TiO3-based ferroelectric ceramics via composition design and grain size tuning

Dielectric energy storage capacitors have been explored to obtain excellent energy storage density along with high energy storage efficiency with the development of electronic devices. In this work, linear dielectric CaTi_0.5Zr_0.5O₃ is introduced into Bi_0.5Na_0.5TiO₃-NaNbO₃ matrix to form 0–3 type composites to vary the size and conductivity of the composite grain, which lead to ultra-high breakdown electric field of 410 kV/cm and the quasi-linear hysteresis loops. Meanwhile, linear dielectric does not change the characteristic of ferroelectric, and thus composites maintain high maximum polarization of 26.4 μC/cm². Integrating the advantages of linear dielectric and ferroelectric, an excellent recoverable energy density of 4.93 J/cm³ with an efficiency of 93.3% have been achieved in BNT-NN/7 wt%CZT ceramics. This work contributes to the development of dielectric energy storage capacitors for practical applications in pulsed power devices.     

Enhanced energy storage density and high efficiency of lead-free Ca1-xSrxTi1-yZryO3 linear dielectric ceramics

Ca_1-xSr_xTi_1-yZr_yO₃ (0.40 ≤ x ≤ 0.60, 0.1 ≤ y ≤ 0.4) ceramic samples were fabricated by conventional solid state method. The microstructure of ceramic samples were studied by XRD and SEM, and the influence of Zr⁴⁺ doping on the electric properties and energy storage performances were systematically studied. The results showed that the introduction of Zr⁴⁺ results in an inhibition of interfacial polarization and enhancement of grain boundary barrier effect. Ca_0.5Sr_0.5Ti_1-yZr_yO₃ ceramic samples exhibit excellent energy storage properties, with breakdown strength being on the order of 390 kV/cm versus 280 kV/cm for the counterpart Ca_0.5Sr_0.5TiO₃ ceramic samples, together with energy efficiency above 95%. Meanwhile, a maximum breakdown strength of 390 kV/cm, a high energy storage density of 2.05 J/cm³ and an ultrahigh energy efficiency of 85% at high temperature of 125 ℃ were obtained in the sample with y = 0.1 as well, indicating it as a good candidate for linear energy storage fileds.     

Enhanced the energy storage performance in AgNbO3‑based antiferroelectric ceramics via manipulation of oxygen vacancy

The applications of silver niobate (AgNbO₃)-based antiferroelectric (AFE) ceramics for potential energy storage are limited by the introduction of oxygen vacancies (OVs). The inevitable OVs narrow the band gap and promote grain growth, resulting in poor breakdown strength and low recoverable energy density (W_rec). Here, we report a significant energy density performance of (Ag_1–2xSr_x)(Nb_0.78Ta_0.22)O₃ AFE ceramics designed by restraining OVs. Electron paramagnetic resonance (EPR) and UVvis absorption spectra experiments demonstrate that the OV content gradually decreases and the band gap increases with increasing Sr content. Donor doping of Sr leads to the generation of silver ion vacancies, thus, the OV concentration decreases to maintain the electrical neutrality of the system. As a result, a high W_rec of ∼5.6 J/cm³ together with an energy efficiency of 70.1% at 300 kV/cm is achieved in the (Ag_0.92Sr_0.04)(Nb_0.78Ta_0.22)O₃ ceramic. This work offers a novel strategy for improving the energy storage properties of AgNbO₃-based AFE ceramics.     

Li+ and Sm3+ co-doped AgNbO3-based antiferroelectric ceramics for high-power energy storage

Ag_1-x-3yLi_xSm_yNbO₃ (x≤0.05, y≤0.05) (ALSN) antiferroelectric ceramics were successfully prepared via conventional solid-state reaction and sinter routes in oxygen atmosphere for improving the energy storage characteristic of pure AgNbO₃. The results indicate that all of the studied compositions display a pure orthorhombic antiferroelectric (AFE) perovskite structure, while their key parameters of electric-field-induced antiferroelectric-ferroelectric transition can be affected by Li⁺ or/and Sm³⁺ doping contents. The Sm³⁺ doping can enhance the stability of antiferroelectric state, giving rise to higher antiferroelectric-ferroelectric transition electric-field (E_F and E_B), while Li⁺ doping can reduce E_F and E_B for Sm³⁺ doped AgNbO₃ with low Sm³⁺ content (y≤0.03). When co-doping the same amounts of Li⁺ and Sm³⁺ at x=y≤0.03, both E_F and E_B almost remain unchanged. At x=y=0.05, the diffuse phase transition (DPT) behavior of antiferroelectric-paraelectric (AFE-PE) phase transition occurred, resulting in a “slim-like” double-polarization hysteresis with significantly enhanced E_F. Due to these features, both W_rec and η are improved compared with pure AgNbO₃. The W_rec and η with composition at x=y=0.05 is 2.33 J/cm³ and 58% under applying electric field of 240 kV/cm, respectively. The results suggest that building DPT behavior of AFE-PE phase transition could be an alternative strategy to improve the energy storage characteristic of AgNbO₃.     

Effect of Sm3+ doping on ferroelectric,energy storage and photoluminescence properties of BaTiO3 ceramics

Rare earth doped ferroelectric ceramics have attracted much attention due to their great potential application for novel multifunctional optical-electro devices. Herein, the x% mol Sm³⁺ doped BaTiO₃ (BTO:xSm³⁺) ceramics were fabricated by the conventional solid-state reaction method. The Sm³⁺ ions composition dependent phase structure, ferroelectric, energy storage and photoluminescence properties were systematically investigated. With the increase of Sm³⁺ ions composition, the remanent polarization decreases dramatically from 15.705 μC/cm² (BTO) to 7.132 μC/cm² (BTO:3.0%Sm³⁺), but the energy storage density and efficiency increase greatly with a relative change of 79.76% and 31.13%, respectively. Furthermore, Sm³⁺ doping causes the transformation from the tetragonal to pseudo-cubic phase for BTO ceramics at room temperature, resulting in a broader temperature transition range from the ferroelectric to paraelectric phase and a lower Curie temperature. Particularly, the pure BTO and BTO:xSm³⁺ ceramics show great thermal stability for energy storage properties. In addition, under the excitation of 408 nm near-ultraviolet light, the BTO:xSm³⁺ ceramics exhibit the strongest orange-red emission peak around 596 nm with a large relative tunability of intensity by 88.97%. The results suggest that the BTO:xSm³⁺ ceramics are suitable for the design of optoelectronic devices.     

Enhanced energy storage and fast discharge properties of BaTiO3 based ceramics modified by Bi(Mg1/2Zr1/2)O3

Lead-free (1-x)BaTiO₃-xBi(Mg_1/2Zr_1/2)O₃ ((1-x)BT-xBMZ) ceramics with perovskite structure were synthesized by solid-state reaction methods. (1-x)BT-xBMZ solid solution transforms from tetragonal (x≤0.04) to pseudocubic (x≥0.08) and exhibits a dispersive dielectric behavior with respect to frequency, showing typical relaxor characteristics with BMZ increasing. The optimal energy storage density of 1.25 J cm^?3 and energy efficiency of >95% are obtained at x = 0.15, with maximum dielectric breakdown strength of 185 kV cm^-1 at 200 μm thickness., The energy storage density and energy efficiency of 0.85BT-0.15BMZ ceramics maintain at about 0.8 J cm^?3 and 89% at 150 kV cm^-1 over temperature range of 25 °C～150 °C, exhibiting good thermal stability. The pulse discharge capability of 0.85BT-0.15BMZ ceramics were measured under different electric fields, showing a short charge-discharge time of 1.3 μs. Therefore (1-x)BT-xBMZ solid solution with high energy density and efficiency, good temperature stability and fast discharge speed, is promising candidate for high power applications.     

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 Ba_0.4Sr_0.6TiO₃ (BST) ceramic exhibits a moderate dielectric constant (ε_r), low dielectric loss and slightly nonlinear P–E hysteresis. However, its energy storage density (W) is extremely low because of its low maximum polarisation (P_max) and weak breakdown strength (BDS). In this study, ferroelectric Na_0.5Bi_0.5TiO₃ (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 (P_r) and high P_max 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 (W_rec = 3.89 J/cm³) and a high energy storage efficiency (η = 83.8%) were realised in the 0.75Ba_0.4Sr_0.6TiO₃-0.25Bi_0.5Na_0.5TiO₃ (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.     

微晶玻璃储能应用研究进展

储能电介质材料是制作脉冲功率电容器的核心材料,在脉冲功率电源、高功率电子器件、高能量密度武器、智能电网系统等基础科研和工程技术领域均有着广阔的前景。微晶玻璃具有很高的电击穿强度,是一类重要的电介质储能材料。本文在简要介绍储能电介质材料的性能评价参数及其相关物理意义的基础上,概述了微晶玻璃储能材料的主要制备方法及其优缺点,重点阐述了微晶玻璃储能材料的主要研究体系及其相关研究进展,最后探讨了微晶玻璃储能材料的未来发展方向及应用前景。     

Improvement of energy storage properties of NaNbO3-based ceramics through the cooperation of relaxation and oxygen vacancy defects

The development of materials with high energy storage plays a crucial role in solving energy consumption. Traditional dielectric ceramics have the disadvantages of low energy storage and low efficiency. The most effective solution is to reduce the dielectric loss and increase the breakdown strength. In this paper, (Na_0.73Bi_0.08Sm_0.01)(Nb_0.91Ta_0.09)O₃ relaxor ferroelectric ceramics were prepared, which achieved a high energy storage density of 1.66 J cm^?3, high efficiency (83.6%) at 214 kV/cm at room temperature. The addition of Bi₂O₃ makes the A site cations disordered, thereby generating random fields, breaking the long-range order, and forming polar nanodomains. That allows the ceramic to acquire relaxation properties, reducing the dielectric loss. The impedance analysis proves that the breakdown strength is related to the addition of Sm₂O₃. The addition of Sm reduces the oxygen vacancy defect concentration and inhibits the migration of carriers, thereby improving its breakdown strength. Through proper doping of Bi and Sm, the relaxation properties and breakdown field strength of the ceramics are enhanced to obtain excellent energy storage performance. This provides a new idea in terms of relaxation and oxygen vacancy defects for NaNbO₃-based energy storage ceramics.     

Enhanced breakdown strength and energy storage density in a new BiFeO3-based ternary lead-free relaxor ferroelectric ceramic

A new ternary lead-free relaxor ferroelectric ceramic of (0.67-x)BiFeO₃-0.33(Ba_0.8Sr_0.2)TiO₃-xLa(Mg_2/3Nb_1/3)O₃+y wt.% MnO₂+z wt.% BaCu(B₂O₅) (BF-BST-xLMN+y wt.% MnO₂+z wt.% BCB) was prepared by a solid-state reaction method. The substitution of LMN for BF was believed to induce a typical dielectric relaxation behavior owing to the increased random fields. After co-doping MnO₂ and BCB, a significant decrease in the conductivity and grain size was simultaneously realized, resulting in obviously enhanced dielectric breakdown strength and energy-storage performances at room temperature. A high recoverable energy storage density W˜3.38 J/cm³ and an acceptable energy storage efficiency η˜59% were achieved in the composition with x = 0.06, y = 0.1 and z = 2 under a measuring electric field of 23 kV/mm. In addition, the energy-storage performance is quite stable against both frequency (0.1 Hz–100 Hz) and temperature (30–170 °C), suggesting that BF-BST-xLMN+y wt.% MnO₂+z wt.% BCB lead-free relaxor ferroelectric ceramics might be a promising dielectric material for high-power pulsed capacitors.     

NaNbO3-based short-range antiferroelectric ceramics with ultrahigh energy storage performance

Lead-free NaNbO₃ (NN) antiferroelectric ceramics provide superior energy storage performance and good temperature/frequency stability, which are solid candidates for dielectric capacitors in high power/pulse electronic power systems. However, their conversion of the antiferroelectric P phase to the ferroelectric Q phase at room temperature is always accompanied with large remnant polarization (P_r), which significantly reduces their effective energy storage density and efficiency. In this study, to optimize the energy storage properties, short-range antiferroelectric (0.95-x)NaNbO₃-xBi(Mg_2/3Nb_1/3)O₃-0.05CaZrO₃ (xBMN) ceramics were designed to stabilize the antiferroelectric phase, in which the local random fields were simultaneously constructed. The results showed that the antiferroelectric orthorhombic P phase was transformed into the R phase, and the local short-range random fields were generated, which effectively inhibited the hysteresis loss and P_r. Of great interest is that the 0.12BMN ceramics displayed a large recoverable energy storage density (W_rec) of 5.9 J/cm³ and high efficiency (η) of 85% at the breakdown strength (E_b) of 640 kV/cm. The material also showed good frequency stability in the frequency range of 2–300 Hz, excellent temperature stability in the temperature range of 20–110 ℃, and a very short discharge time (t_0.9∼4.92 μs). These results indicate that xBMN ceramics have great potential for advanced energy storage capacitor applications.     

High energy storage density and discharging efficiency in La3+/Nb5+-co-substituted (Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics

In this work, [(Bi_1-xLa_x)_0.5Na_0.5]_0.94Ba_0.06(Ti_1-5y/4Nb_y)O₃ ceramics have been developed by the dual-substitution of La³⁺ for Bi³⁺ and Nb⁵⁺ for Ti⁴⁺ and prepared by an ordinary sintering technique. All ceramics can be well-sintered at 1200 °C. The addition of La³⁺ and Nb⁵⁺ reduces the grain size and improve the dielectric breakdown strength of the ceramics; moreover, after the introduction of La³⁺ and Nb⁵⁺, the remanent polarization of the ceramics is significantly reduced, while the maximum polarization remains the same large value as that of the ceramic without the doping of La³⁺ and Nb⁵⁺. As a result, high energy storage density and discharge efficiency are achieved at x/y = 0.07/0.02, giving the large storage density of 1.83 J/cm³ and high discharging efficiency of 70%. The present work presents a feasible strategy to develop energy storage materials based on perovskite ferroelectrics by the partial substitutions in the A and B sites.     

Crystal structure,relaxor behaviors and energy storage performance of (Sr0.7Ba0.3)5LaNb7Ti3O30 tungsten bronze ceramics

In this work, a new (Sr_0.7Ba_0.3)₅LaNb₇Ti₃O₃₀ system ceramic with a filled tetragonal tungsten bronze structure was proposed and fabricated by the traditional solid phase method. Crystal structure, relaxor behaviors and energy storage capabilities were studied. Large relaxor activation energy indicates a “weakly coupled relaxor” mechanism, which is advantageous for obtaining better energy storage performance, and lower conductance activation energy can further prove the formation of the filled tungsten bronze structure. More importantly, a dielectric breakdown strength of up to 35.5 kV/mm was obtained. The releasable energy density and efficiency at 24 kV/mm are 1.36J/cm³ and 91.9%, respectively. In addition, due to the high current density and high dielectric breakdown strength, a current density of 477.5 A/cm² and a power density of 42.9 MW/cm³ are achieved, meaning that SBLNT ceramic is a potential candidate dielectric ceramic for energy storage.     

Designing novel lead-free NaNbO3-based ceramic with superior comprehensive energy storage and discharge properties for dielectric capacitor applications via relaxor strategy

There are urgent demands for high performance capacitors with superior energy storage density and discharge performances. In this work, novel NaNbO₃-based lead-free ceramics (0.91NaNbO₃-0.09Bi(Zn_0.5Ti_0.5)O₃) with high energy storage capability, high power density and fast discharge speed were designed and prepared. Bi(Zn_0.5Ti_0.5)O₃ was chosen for the purpose to reduce the remnant polarization and improve the induced polarization. Consequently, a large stored energy storage density (W_s˜ 3.51 J/cm³) and high recoverable energy storage density (W_rec˜ 2.20 J/cm³) were obtained in 0.91NaNbO₃-0.09Bi(Zn_0.5Ti_0.5)O₃ ceramic under a high breakdown strength of 250 kV/cm, with excellent thermal stability in the range of 20–120 °C. More importantly, the investigated ceramics exhibited high power density (P_D˜ 20 MW/cm³) and ultrafast discharge rate (t_0.9˜ 0.25 μs), demonstrating potential application in pulse powehr systems. This work provides an effective means of achieving excellent energy storage and discharge performances in NaNbO₃-based ceramics for application in dielectric capacitors.     

Combining high energy efficiency and fast charge-discharge capability in calcium strontium titanate-based linear dielectric ceramic for energy-storage

The high energy density and power density dielectric ceramics with wide frequency and temperature stability are competitive materials for pulse power capacitors. This research proposes an effective strategy for enhancing energy storage performance of Ca_0.5Sr_0.5TiO₃ ceramics through the introduction of Sn⁴⁺ ion. This ion restrains grain growth, increases high insulating grain boundaries, and thus enhances the barrier height of grain boundaries, which are demonstrated in SEM micrographs and complex impedance. The Ca_0.5Sr_0.5Ti_0.97Sn_0.03O₃ (SnCST3) ceramics possess high energy storage density of 2.06 J/cm³ and efficiency of 95% under breakdown strength of 330 kV/cm, which get benefit from wide band gap of 5.3 eV. While the exceptional stability with minimal fluctuation (<15%) in the wide frequency range of 1–1000 Hz and temperature range of 20–120 °C are also achieved in this system. Furthermore, the pulse discharge performance are performed to appraise practical applications of pulse power capacitors. The prominent power density of 32.2 MW/cm³ and current density of 537.4 A/cm² are obtained. Meanwhile, stored energy are released in very short duration of 13 ns as well as outstanding temperature stability is realized in the temperature range of 20–120 °C for the SnCST3 ceramic, confirming it as one competitor for lead-free high power capacitors.     

Enhanced energy storage properties of BaO-K2O-Nb2O5-SiO2 glass ceramics obtained through microwave crystallization

BaO-K₂O-Nb₂O₅-SiO₂ (BKNS) glass ceramics were prepared by microwave crystallization of transparent glass matrices and the effects of microwave treatment temperature on their dielectric performances, phase structure, microstructure and breakdown strength (BDS) were investigated systematically. X-ray diffraction results suggested that microwave treatment had no significant influence on the type of precipitated phases. The microstructure of the glass ceramics was remarkably optimized via microwave treatment. The dielectric constant and breakdown strength of microwave-treated samples were significantly improved as compared with conventional-heated samples at the same temperature. The maximum theoretical energy storage density of microwave-treatment samples at 750?°C reached 12.7?J/cm³, which was larger than that of the conventional-heated samples (8.6?J/cm³).     

Enhanced dielectric breakdown strength in TiO2-SiO2-Al2O3 based ceramics prepared through hot-press assisted liquid phase sintering

Linear dielectric ceramics have received much attention due to high power density, fast discharge speed and ultralow dielectric loss, which are expected as promising candidates for the pulsed power system applications. However, their relatively low dielectric breakdown strength usually cannot meet the requirements of practical application. In this work, we adopt hot-press sintering method to enhance the dielectric breakdown strength of the TiO₂-SiO₂-Al₂O₃ based ceramics, and the dielectric breakdown strength reaches 77.5 kV/mm, which is 1.8 times as large as samples prepared by conventional sintering method. The effect of different sintering methods on microstructure, dielectric properties and dielectric breakdown strength is investigated. The improvement of dielectric breakdown strength can be ascribed to improved bulk density, smaller grain size, and reduced reduction of Ti⁴⁺ to Ti³⁺, associated with the applied external pressure and lower sintering temperature. Eventually, large power density (18.20 MW/cm³) is obtained in pulse overdamped discharge circuit. Meanwhile, the stored energy is also released in a short time (about 11.3 ns to release 90% of saturated energy density value).     

High energy storage performance in BaTiO3-based lead-free relaxors via multi-dimensional collaborative design

The application of advanced pulse power capacitors strongly depends on the fabrication of high-performance energy storage ceramics. However, the low recoverable energy storage density (W_rec) and energy efficiency (η) become the key links limiting the development of energy storage capacitors. In this work, a high W_rec of ～5.57 J cm^?3 and a large η of ～85.6% are simultaneously realized in BaTiO₃-based relaxor ceramics via multi-dimensional collaborative design, which are mainly attributed to the ferroelectric-relaxor transition, enhanced polarization, improved breakdown electric field, and delayed polarization saturation. Furthermore, the excellent temperature stability (ΔW_rec < ± 5%, 25–140 °C), frequency stability (ΔW_rec < ± 5%, 1–200 Hz), and outstanding charge/discharge performance (current density ～1583.3 A cm^?2, power density ～190.0 MW cm^?3) with good thermal stability are also achieved. It is encouraging that this work demonstrates that multi-dimensional collaborative design is a good strategy to develop new high-performance lead-free materials used in advanced dielectric capacitors.     

Enhanced energy storage properties of Bi0.5Na0.5TiO3-based ceramics via regulating the doping content and sintering temperature

Eco-friendly lead-free energy-storage ceramics featuring high energy storage properties and ultra-high stability have been regarded to be one of the most potential materials in the field of energy storage. In this work, a new element system, (1-x)(0.6Bi_0.5Na_0.5TiO₃-0.4SrTiO₃)-xBi[Zn_2/3(Nb_0.5Ta_0.5)_1/3]O₃ ((1-x)BNST-xBZNT) lead-free ceramics, were synthesized via a conventional solid-state sintering technology. And the phase structure, microstructure and energy storage properties of the (1-x)BNST-xBZNT ceramics were comprehensively studied. After the introduction of BZNT, the average grain size of the materials is greatly decreased, thereby enhancing the dielectric breakdown strength (DBS). Additionally, the thermal stability of the ceramics is significantly improved via regulating the doping content and sintering temperature. Furthermore, the ferroelectric long-range order of the ceramics is decomposed into randomly-oriented polar nano-domains (PNRs) after introducing BZNT, leading to strong relaxor behavior and significantly reducing remanent polarization (P_r). As a result, even under a relatively low electric field of 139 kV/cm, the 0.98BNST-0.02BZNT ceramic sintered at 1150 °C possesses high values of energy storage efficiency (η) value of 92.78% and total energy storage density (W_tot) of 1.67 J/cm³ as well as remarkable thermal stability (25–175 °C), frequency stability (20–70 Hz) and fatigue resistant stability (10⁰-10⁵ cycles). This investigation provides a useful reference for developing advanced energy storage ceramics by regulating the doping content and sintering temperature.