Ultrafast Discharge Research Articles

Combustion synthesis of high-performance high-entropy dielectric ceramics for energy storage applications

High-entropy dielectric ceramics have demonstrated a promising prospect for applications in energy storage recently. However, most high-entropy dielectrics synthesized by conventional solid-state reaction (SSR) method demonstrated unsatisfactory performance for energy storage. Therefore, it is meaningful to develop a feasible way to fabricate high-performance high-entropy dielectric ceramics. Herein, high-entropy (Sr0.6Bi0.2Na0.2)(Ti1-xZrx/2Alx/4Nbx/4)O3 ceramics are prepared by a solution combustion synthesis (SCS) method. The SCS fabricated ceramics (x = 0.25) demonstrate a high recoverable energy density of ∼4.46 J/cm3 at a high critical electric field of 520 kV/cm, a high energy efficiency ∼88.52%, a large power density of ∼176.65 MW/cm3 (at 400 kV/cm), an ultrafast discharge time of ∼48 ns, and a high Vikers hardness of ∼7.09 GPa. The key energy storage parameters are much better than those of the samples prepared by the SSR method owing to the absence of unexpected impurity phases, and the refined grain size at the submicrometer scale in our SCS fabricated high-entropy ceramics. The study provides a facile way to fabricate high-performance high-entropy dielectric ceramics for energy storage, indicating that the SCS routine is notably advantageous for preparing high-entropy dielectric energy ceramics.

High energy storage performance in Sr0.64Bi0.18Na0.18TiO3-ZnO hybrid solid solution ceramics

Ceramic-based capacitors with excellent recoverable energy storage density (Wrec) and efficiency (η) are greatly desired for pulsed capacitors but challenge as well. In this work, the high energy storage performance with an Wrec of 5.1 J/cm3, an η of 93.4%, and an ultrafast discharge–charge speed t0.9 of 72 ns is achieved in unusual interstitial and substitutional hybrid solid solution of Sr0.64Bi0.18Na0.18TiO3-ZnO (SBNT-Zn), in which two Zn2+ ions occupy one A-site, while one Zn2+ ion occupies one B-site of ABO3 perovskite lattice simultaneously. The addition of Zn2+ increases lattice distortion and breaks long-range ferroelectric order, resulting in more highly dynamic polar nanoregions, higher relaxation behaviors as well as larger polarization (ΔP). Moreover, the extraordinary hybrid solid solution configuration enhances the bandgap of SBNT-Zn and ZnO as a sintering aid refines grain size, both help to enhance electric breakdown strength. This work affirms the feasibility and reliability of forming a hybrid solid solution to develop high-performance ferroelectric materials.

Superior Energy Density Achieved in Unfilled Tungsten Bronze Ferroelectrics via Multiscale Regulation Strategy.

The most promising candidates for energy storage capacitor application are relaxor ferroelectrics, among which, the perovskite structure ferroelectric ceramics have witnessed great development progress. However, less attention has been paid on tetragonal tungsten bronze structure (TTBS) ceramics because of their lower breakdown strength and polarization. Herein, a multiscale regulation strategy is proposed to tune the energy storage performances (ESP) of TTBS ceramicsfrom grain, domain, and macroscopic scale. The enhanced relaxor behavior with dynamic polar nanodomains guarantees low remanent polarization, while the refined grains and enlarged bandgap ensure increased breakdown strength. Hence, excellent ESP isrealized in unfilled TTBS Sr0.425 La0.1 □0.05 Ba0.425 Nb1.4 Ta0.6 O6 (SLBNT) ceramics with an ultrahigh recoverable energy density of 5.895 J cm-3 and a high efficiency of 85.37%. This achievement notably surpasses previous studies in TTBS ceramics and is comparable to that of perovskite components. Meanwhile, the energy density exhibits a wide temperature, frequency, and cycling fatigue stability. In addition, high power density (257.89 MW cm-3 ), especially the ultrafast discharge time (t0.9 = 16.4ns) are achieved. The multiscale regulation strategy unlocks the energy storage potential of TTBS ceramics and thus highlights TTBS ceramicsas promising candidates for energy storage, like perovskite structured ceramics.

Interfacial Polarization Restriction for Ultrahigh Energy‐Storage Density in Lead‐Free Ceramics

AbstractDielectric capacitors with high power densities are crucial for pulsed electronic devices and clean energy technologies. However, their breakdown strengths (Eb) strongly limit their power densities. Herein, by modifying the interfacial polarization by adjusting the difference in activation energies (Δϕ) between the grain and grain boundary phases, the significant enhancement of Eb in the (1‐x)(0.94Na0.5Bi0.5TiO3‐0.06BaTiO3)‐xCa0.7La0.2TiO3 (NBT‐BT‐xCLT, x = 0, 0.18, 0.23, 0.28, 0.33, 0.38, and 0.43) ceramics is achieved. The results indicate that adding CLT introduces a super‐paraelectric state, refines grain size, and, most importantly, decreases the Δϕ value. When Δϕ is tuned close to zero in the specific NBT‐BT‐0.38CLT sample, a significant boost in Eb value of 64 kV mm−1 is obtained. As a result, the recoverable energy storage density of the ceramics reaches an unprecedented giant value of 15.1 J cm−3 together with a high efficiency of 82.4%, as well as ultrafast discharge rate of 32 ns, and high thermal and frequency stability. The results demonstrate that interfacial polarization engineering holds huge promise for the development of dielectrics with high‐energy‐storage performance.

Ultra-fast development of Ar 2p relative densities in nanosecond-pulsed barrier discharge in argon

A time-correlated single photon counting based optical emission spectroscopy technique is applied for an investigation of the nanosecond-pulsed barrier discharge in atmospheric pressure argon gas. We record the development of the light intensities originating from all ten Ar 2p (Paschen notation) radiative states with high spatio-temporal resolution. We identify different stages of the discharge development: an early rapid electron avalanching, streamer propagation phase, generation of discharge channel and surface streamer propagation over the dielectric surface. The quantified relative 2p densities for identified discharge phases enable a well-resolved insight into the ultra-fast discharge kinetics and open a possibility for the development of future detailed diagnostics of the rapidly ionized argon plasmas. Moreover, the electrical characterization of the discharge is made using the simplest equivalent circuit and it reveals new findings for the application of such an approach for similar discharges.

Excellent energy storage properties realized in novel BaTiO3-based lead-free ceramics by regulating relaxation behavior

BaTiO3(BT) has attracted extensive attention among advanced lead-free ferroelectric materials due to its unique dielectric and ferroelectric properties. However, the enormous remanent polarization and coercive field severely impede the improvement of its energy storage capabilities. Here, the BaTiO3Bi(Zn0.5Hf0.5)O3 (BT-BZH) ceramics with high breakdown field strength and remarkable relaxation characteristics can be obtained by introducing the composite component BZH in BT to regulate the phase structure and grain size of the ceramics. The findings demonstrate that the improvement of energy storage performance is related to the increase of relaxation behavior. A large energy storage density (Wrec∼3.62 J/cm3) along with superior energy storage efficiency (η∼88.5%) is achieved in 0.88BT-0.12BZH relaxor ceramics only at 240 kV/cm. In addition, the sample suggests superior thermal stability and frequency stability within 25–115 °C and 1–500 Hz, respectively. Furthermore, the outstanding charge-discharge properties with an ultrafast discharge time (100 ns), large discharged energy density (1.2 J/cm3), impressive current density (519.4 A/cm2) and power density (31.1 MW/cm3) under the electric field of 120 kV/cm are achieved in studied ceramics. The excellent energy storage performance of BT-BZH ceramics provides a promising platform for the application of lead-free energy-storage materials.

Improved energy storage performance of Ba(Ti,Ca)O3 ceramics through tailoring phase structure and ferroelectric polarization

A novel strategy was adopted to prepare (1 − x)Ba(Ti0.97Ca0.03)O2.97–x(Bi0.51Na0.47)0.94Ba0.06TiO3 (abbreviated as (1 − x)BTC–xBNBT, x = 0.03–0.15) relaxor ferroelectric ceramics by precisely tailoring the phase structure and ferroelectric polarization. Significant enhancements in both polarization and dielectric breakdown strength are successfully achieved by realizing the phase structure dominated by the tetragonal phase in relaxor ferroelectrics. Notably, the 0.9BTC–0.1BNBT ceramic simultaneously shows an outstanding recoverable energy density of 2.17 J cm−3 and a high efficiency of 84.5% at 240 kV cm−1, as well as superior temperature (20 °C–160 °C) and frequency (1–100 Hz) stability. In addition, the charge–discharge test results show that the 0.9BTC–0.1BNBT ceramic has an ultra-fast discharge rate of t 0.9 ∼ 75 ns, an ultra-high power density of 27.7 MW cm−3 and a high discharge energy density of 0.58 J cm−3. This work not only provides a promising energy storage material for pulse capacitors, but also presents an effective method for developing new high-performance BaTiO3-based dielectric materials.

Enhanced breakdown strength and excellent energy storage stability by B site hetero-valent doping in Sr0.7Bi0.2TiO3-based lead-free ceramic

Environment-friendly energy storage materials are embraced in global researches. Aiming at improving the energy storage performances of lead-free dielectric ceramics, the Sr0.7Bi0.2Ti(1–1.25x)NbxO3 (SBT-xN, x = 0 ∼ 0.125) lead-free ceramics were synthesized via the conventional solid state method in this work. Outstanding total energy storage density (Wtotal = 3.998 J/cm3), recoverable energy storage (Wrec = 3.43 J/cm3), and high energy storage efficiency (η of 85.84%) were obtained when x = 0.075 under the electric field of 385 kV/cm. Meanwhile, a satisfied temperature (30 ℃−110 ℃ variation less than 14%), frequency stability (10–400 Hz variation less than 1%), and anti-fatigue characteristic (107 cycles variation less than 1%) were achieved. Furthermore, the sample exhibited a remarkable discharge energy density (Wd = 3.885 J/cm3), ultrafast discharge speed (t0.9 = 73 ns), and giant discharge power density (Pd = 327.01 MW/cm3) at 400 kV/cm in charge-discharge tests. Great temperature stability (30 ℃−150 ℃ variation less than 8%) and pulse repetition frequency discharge stability (2×105 times variation less than 3.5%) were also obtained. The excellent characteristics suggest that the ceramic is a prospective candidate for advanced pulse power equipment.

NaNbO3-(Bi0.5La0.5)(Mg2/3Ta1/3)O3 lead-free ceramics achieve ultrafast discharge rate and excellent energy storage performance

NaNbO3-(Bi0.5La0.5)(Mg2/3Ta1/3)O3 lead-free ceramics achieve ultrafast discharge rate and excellent energy storage performance

Multi-ratio optical thermometry and energy storage characteristics of Yb3+/Er3+/Tm3+ doped BaNb2O6 transparent glass-ceramics

• RE-doped BaNb 2 O 6 transparent glass ceramics (GCs) were fabricated firstly. • Realizing three-mode Up-conversion optical thermometry in the GCs. • The maximum S r-max and S a-max can reach 2.30% K –1 and 6.71‰ K –1 . • Achieving high W d of 0.99 J cm –3 and high P d of 225.3 MW cm –3 . • Multifunctional GCs can be used in optical sensing and energy storage fields. In order to meet the needs of new materials gradually developing towards miniaturization, integration, and light weight, multifunctional BaNb 2 O 6 : Yb 3+ /Er 3+ /Tm 3+ transparent glass-ceramics were successfully prepared by melt quenching and controllable crystallization. Its structure, luminescence, and energy transmission were studied. Using the opposite temperature dependence of the Tm 3+ emission band and the corresponding large energy level gap, a maximum relative sensitivity of 2.3% K –1 based on thermal coupling levels (TCLs) is obtained in a wide temperature range (298–673 K). The multi-ratio optical thermometry based on TCLs and non-TCLs is successfully realized by using the different emission bands of double emission centers, which makes it possible for self-reference optical temperature measurement modes. In addition, the transparent glass-ceramic exhibits excellent electrical properties under 700 kV cm –1 electric field: high discharge energy density ( W d = 0.99 J cm –3 ), huge instantaneous power density (225.3 MW cm –3 ), and ultra-fast discharge rate ( T 0.9 ≤ 15.8 ns). The prepared glass-ceramic is expected to be a new type of lead-free multifunctional photoelectric material for temperature sensors and transparent electronic devices.

Boosting energy-storage performance in lead-free ceramics via polyphase engineering in the superparaelectric state

Dielectric energy storage devices are important components of high-power and pulsed electronic systems. High recoverable energy density (Wrec) and high efficiency (ƞ) are critical parameters for such applications. In this work we propose a strategy of polyphase engineering in the superparaelectric (SPE) state to achieve high-performance energy storage. Through careful engineering of the proportions of rhombic (R) phase and tetragonal (T) phase by a linear dielectric additive, CaTi0.8Hf0.2O3 (CTH), in 0.94Na0.5Bi0.5TiO3-0.06BaTiO3-based ceramics, the SPE state can be shifted to ambient temperature when R/T ≤ 0.16. Thanks to the features of isolated polar nano-domains (PNRs) and the fine P-E hysteresis loop of the SPE state, an ultrahigh Wrec of 8.91 J/cm3 and high ƞ of 78.4% are achieved in our 0.75(0.94Na0.5Bi0.5TiO3-0.06BaTiO3)-0.25CaTi0.8Hf0.2O3 sample. The sample was also characterized by excellent temperature and frequency stability, achieving ultra-high power density (178 MW/cm3) and ultra-fast transient discharge time (40 ns). Our work proves that polyphase engineering in the SPE state is a powerful approach to the design of dielectric energy storage materials with high performance.

High energy-storage performance in X9R-type Na0.5Bi0.5TiO3-based lead-free ceramics

KaTaO3 (KT) modified Na0.5Bi0.5TiO3–BaTiO3 lead-free ceramics (1-x)(0.94Na0.5Bi0.5TiO3-0.06BaTiO3)-xKTaO3 (NBT-BT-xKT, x = 0.20, 0.25, 0.30, and 0.35) were fabricated via the solid-state reaction method. The effect of KT modification on the structural, dielectric, and energy-storage properties of the ceramics were systematically investigated. Our results show that the NBT-BT-xKT sample shows excellent thermal stability of dielectric constant (Δε′/ε25oC′ ≤ ±15%) over the temperature range of -60-215 °C with very low loss (≤0.02). Meanwhile, a large energy storage density (Wrec = 4.89 J/cm3), excellent efficiency (η = 84%), and an ultrafast discharge rate of 29 ns were also achieved in the NBT-BT-0.3 KT ceramic. This work indicates that the NBT-BT-0.30 KT sample would be a promising material for pulsed electrical applications working in extreme environments.

Ultrahigh energy density and excellent discharge properties in Ce4+ and Ta5+ co-modified AgNbO3 relaxor antiferroelectric ceramics via multiple design strategies

Silver niobate (AgNbO3) has been recently regarded as one of the best candidates for developing high-performance dielectric capacitors on account of its large maximum polarization and near-zero remnant polarization, but its room-temperature ferrielectric (FIE) behavior and large electric hysteresis impede further improvement of energy storage properties. In order to solve this issue, herein, we design Ce4+ and Ta5+ co-modified (Ag0.96Ce0.01)(Nb1-xTax)O3 relaxor antiferroelectric (AFE) ceramics. The introduction of Ce4+ and Ta5+ decreases the tolerance factor, reduces the B-site cation polarizability, and enhances A- and B- site cation disorder, leading to suppressed FIE characteristic, improved AFE stability, and enhanced relaxor degree. Besides, the co-doping strategy causes the decrease of the grain size, and the experimental results and finite element simulations both indicate that this is fairly effect on the improvement of the breakdown strength. Consequently, an ultrahigh recoverable energy density of 7.37 J/cm3, which far exceeds those of the latest AgNbO3-based ceramics, and a large efficiency of 75.66% are simultaneously achieved in (Ag0.96Ce0.01)(Nb0.7Ta0.3)O3 ceramics. More encouragingly, the ceramic exhibits excellent actual discharge capacity with ultrafast discharge time of 23 ns and ultrahigh power density of 294.28 MW/cm3, which outperforms many recently reported lead-free dielectric ceramics, and the discharge properties are fairly stable during a wide temperature range of 20–180 °C. This work sheds light on designing and developing high-performance lead-free dielectric capacitors applicable in harsh environment.

Analysis and design of battery thermal management under extreme fast charging and discharging

Thermal management is critical for the safety of electric vehicle (EV) battery packs, especially under ultra-fast and extreme fast charging and discharging use conditions. Liquid cooling is particularly attractive over other battery thermal management technologies due to its high heat transfer coefficient and low power usage. This paper systematically studies a liquid-cooled battery thermal management system for limiting the maximum temperature and voltage excursions of a standard 18650 lithium-ion battery pack. Considering two different coolant flow configurations, the influences of coolant flow rate, inlet temperature, battery capacity, charge rate, and discharge rate are investigated through a detailed computational study. Based on the simulations, design windows are developed for keeping the maximum temperature during charging below 45 °C and during discharging within 60 °C, as well as maintaining the cell voltage < 4.2 V. The design windows provide the maximum charge and discharge rates that can be achieved with a given coolant flow rate and inlet temperature for a battery capacity. Equivalently, the design windows may be utilized for a desired charge and discharge rate to obtain the required coolant flow design. The study provides valuable insight into advancing the ultra and extreme fast charge and discharge capabilities of battery packs for EV applications.

Superior Energy and Power Density Realized in Pb(Hf 1- x Ti x )O 3 System at Low Electric Field

The development of antiferroelectric materials with large energy density and fast discharge speed makes dielectric capacitors possess great prospects for applications in pulsed power technology. Here, the PbHfO 3 -based ceramics with compositions of Pb(Hf 1- x Ti x )O 3 (PHT, 0.01 ≤ x ≤ 0.05) were synthesized, and their antiferroelectricity and phase transition behavior were studied. According to the tests of x-ray diffraction, dielectric spectrum, and polarization–electric field hysteresis loops, PHT ceramics gradually transition from an orthorhombic symmetric antiferroelectric phase to a hexagonal symmetric ferroelectric phase at room temperature as Ti 4+ concentration increases. The forward phase switching field of antiferroelectric to ferroelectric phase transition can be markedly regulated by the introduction of Ti 4+ , and the optimal energy storage performance was obtained in Pb(Hf 0.98 Ti 0.02 )O 3 ceramics with a large recoverable energy storage density of W rec ~ 4.15 J/cm 3 and efficiency of η ~ 65.3% only at a low electric field of 190 kV/cm. Furthermore, the outstanding charge–discharge properties with an ultrafast discharge time (71 ns), remarkable discharged energy density (2.84 J/cm 3 ), impressive current density (1,190 A/cm 2 ), and ultrahigh power density (101 MW/cm 3 ) at a low electric field of 170 kV/cm were obtained in studied ceramics. The excellent energy storage performance of PHT ceramics provides a promising platform for the application of dielectric capacitors.

Superior energy storage performance and ultrafast discharge of NBBT-based ceramics via introducing linear dielectric additives and rare earth oxides

Ferroelectric ceramics have low energy storage performance due to their nearly square hysteresis loops and low dielectric breakdown strength, which affects their practical applications for high-power energy storage capacitors.

Large energy density and high efficiency achieved simultaneously in Bi(Mg0.5Hf0.5)O3-modified NaNbO3 ceramics

A novel lead-free relaxor ferroelectric ceramics, (1-x)NaNbO3-xBi(Mg0.5Hf0.5)O3[NN-xBMH, x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25] were designed and fabricated for the first time via the standard solid-phase reaction method. The dielectric, ferroelectric, and impedance properties of the NN-xBMH ceramics were tested. Normal ferroelectrics were induced into relaxor ferroelectrics with the introduction of BMH, and the hysteresis loops became slender; This is beneficial to improve the energy storage density and efficiency of ceramic capacitors. Superior breakdown strength (370 kV/cm) is achieved in NN-0.20BMH ceramic with the recoverable energy storage density (Wrec = 3.51 J/cm3) and efficiency (η = 93.77 %). In addition, excellent frequency (1–1000 Hz) and temperature (30–120 °C) stability shows that ceramics have the actual potential in the application of ceramic capacitor.Excellent charge and discharge performances with a high power density (PD = 118 MW/cm3) and current density (CD = 990 A/cm2) along with an ultra-fast discharge rate (50 ns) were gained.

Phase and Band Structure Engineering via Linear Additive in NBT-ST for Excellent Energy Storage Performance with Superior Thermal Stability.

Lead-free relaxor ferroelectric ceramics with ultrahigh energy-storage performance are vital for pulsed power systems. We herein propose a strategy of phase and band structure engineering for high-performance energy storage. To demonstrate the effectiveness of this strategy, (1 - x)(0.75Na0.5Bi0.5TiO3-0.25SrTiO3)-xCaTi0.875Nb0.1O3 (NBT-ST-xCTN, x = 0.1, 0.2, 0.3, 0.4, and 0.5) samples were designed and fabricated via the solid-state reaction method. The linear dielectric CTN was used as a modulator to tune both phase and band structures of the tested system. Our results show that both rhombohedral phase (R-phase) and tetragonal phase (T-phase) coexist in the samples. The R/T ratio decreases, while the band gap increases with increasing CTN content. The best energy-storage properties with large energy storage density (Wrec = 7.13 J/cm3), a high efficiency (η = 90.3%), and an ultrafast discharge time (25 ns) were achieved in the NBT-ST-0.4CTN sample with R/T = 0.121. Importantly, along with its excellent energy-storage performance, the sample exhibited superior thermal stability with the variations of Wrec ≤ 7% and η ≤ 10% over the wide temperature range of 233-413 K. This work suggests that this engineering of phase and band structures is a promising strategy to achieve superior energy-storage properties in lead-free ceramics.

Glass-Ceramic Capacitors with Simultaneously High Power and Energy Densities under Practical Charge-Discharge Conditions.

Developing dielectric capacitors with both a high power density and a high energy density for application in power electronics has been a long-standing challenge. Glass-ceramics offer the potential of retaining the high relative permittivity of ceramics and at the same time of exhibiting the high dielectric breakdown strength and fast charge/discharge rate of glasses, thus producing concurrently high power and energy densities in a single material. In this work, glass-ceramics are fabricated to achieve simultaneously high power and energy densities, high efficiency, and thermal stability by tuning the glass crystallization process via a suitable nucleating agent and a high oxygen partial pressure. Under the same practical charge-discharge test conditions, the as-prepared glass-ceramics combine the high energy density of ceramics and ultrafast discharge rate of glasses, producing the highest power density among glass- and ceramic-based dielectric materials. This work demonstrates the significant potential of achieving both high power and energy densities in glass-ceramics by optimizing the glass crystallization process.

Realizing ultrahigh breakdown strength and ultrafast discharge speed in novel barium titanate-based ceramics through multicomponent compounding strategy

Lead-free dielectric ceramics have been an important segment in the energy storage field. In this work, a synergistic optimization strategy of multicomponent compounding involving 0.9[0.88Ba1-xCaxTiO3-0.12Bi(Mg2/3(Nb0.85Ta0.15)1/3)O3]− 0.1Bi0.5Na0.5TiO3 (B1-xCxT-BMNT-BNT) ceramics were proposed. With the increase of Ca2+ content (x), the content of the CaTiO3 phase increases, which obviously enhances the breakdown strength (BDS) and energy storage properties. The optimal energy storage performances were obtained in the B0.6C0.4T-BMNT-BNT ceramic, showing a large recoverable energy density (Wrec) of 3.59 J/cm3 and ultrahigh efficiency (η) of 90.86% at 430 kV/cm. Meanwhile, the B0.6C0.4T-BMNT-BNT material also exhibits good temperature stability (20–180°C), frequency stability (1–500 Hz) and fatigue resistant (1–105 cycles). In addition, the B0.6C0.4T-BMNT-BNT ceramic also possesses ultrafast discharge time (t0.9 = 38.6 ns) in the charge and discharge test. The above merits make the B0.6C0.4T-BMNT-BNT ceramic a promising candidate for wide-temperature dielectric capacitors in pulse power applications.