Enhanced Energy Storage Properties Research Articles

Enhanced Energy Storage Properties and Dielectric Stabilities in Bnt-Based Ceramics Via Multiphase and Dielectric Peak Broadening Engineering

Enhanced Energy Storage Properties and Dielectric Stabilities in Bnt-Based Ceramics Via Multiphase and Dielectric Peak Broadening Engineering

Enhanced energy storage properties of KNbO3 modified (Bi0.5Na0.5)TiO3–BaTiO3 based lead-free relaxor ferroelectric ceramics

KNbO3 doping is used to increase the relaxor degree, reduce the remanent polarization, and improve the energy storage performance.

Remarkably enhanced recoverable energy density in lead-free relaxor Ba0.94Ca0.06Ti1−xSnxO3 ceramics by the synergistic effect of nano-domains and refined grains

High-performance dielectric ceramic capacitors is a promising candidate in energy storage devices. In this work, the energy storage performance of Ba0.94Ca0.06Ti1−xSnxO3 (x = 0.04, 0.08, 0.12, 0.16) ceramics was systematically studied. Through modifying Sn4+ doping content, the breakdown strength of the ceramics is enhanced by 112.3% from 133.4 kV/cm (Ba0.94Ca0.06Ti0.96Sn0.04O3) to 283.2 kV/cm (Ba0.94Ca0.06Ti0.84Sn0.16O3). Accordingly, the recoverable energy density is greatly increased by 276.2%, that is, from 0.42 J/cm3 grow to 1.58 J/cm3. The enhanced energy storage properties could be ascribed to the following aspects: (1) the doping of Sn4+ with a larger ionic radius inhibits the migration of grain boundaries and therefore refines grains, resulting in a higher activation energy and a larger Eb; (2) the long range polar order is broke and polar nano-regions are formed, giving rise to lower energy barrier and smaller Pr; (3) the weakened ferroelectricity and delayed polarization saturation lead to higher Wrec owing to the fact that Sn4+ with d10 electronic configurations substitutes Ti4+ with d0. Our work provides a novel approach for enhancing energy storage performance in dielectric ceramic capacitors.

Enhanced energy storage properties and antiferroelectric stability of Mn-doped NaNbO3-CaHfO3 lead-free ceramics: Regulating phase structure and tolerance factor

NaNbO3-based ceramics usually show ferroelectric-like P-E loops at room temperature due to the irreversible transformation of the antiferroelectric orthorhombic phase to ferroelectric orthorhombic phase, which is not conducive to energy storage applications. Our previous work found that incorporating CaHfO3 into NaNbO3 can stabilize its antiferroelectric phase by reducing the tolerance factor (t), as indicated by the appearance of characteristic double P-E loops. Furthermore, a small amount of MnO2 addition effectively regulate the phase structure and tolerance factor of 0.94NaNbO3-0.06CaHfO3 (0.94NN-0.06CH), which can further improve the stability of antiferroelectricity. The XRD and XPS results reveal that the Mn ions preferentially replace A-sites and then B-sites as increasing MnO2. The antiferroelectric orthorhombic phase first increases and then decreases, while the t shows the reversed trend, thus an enhanced antiferroelectricity and the energy storage density Wrec of 1.69 J/cm3 at 240 kV/cm are obtained for 0.94NN-0.06CH-0.5%MnO2(in mass fraction). With the increase of Mn content to 1.0 % from 0.5 %, the efficiency increases to 81 % from 45 %, although the energy storage density decreases to 1.31 J/cm3 due to both increased tolerance factor and non-polar phase.

Enhanced energy storage properties of BNT-based ceramics by maintaining the high saturation polarization

Miniaturization is the key for development of lightweight energy storage ceramics. Here, lead-free ceramics with the formula (1-x) (0.94Bi0.5Na0.5TiO3-0.06BaTiO3)-xSr0.7La0.2TiO3 (BNT-6BT-xSLT) were successfully sintered using traditional solid-phase synthesis. The phase structure, micro-morphology, ferroelectricity, and energy storage efficiency and density of BNT-6BT-xSLT were investigated in this work. We found that the introduction of SLT does not alter the multi-phase coexistence of the ceramics, but inhibits the growth of crystal grains. Further, doping with Sr2+ and La3+ destroys the ferroelectric long-range order and enhances the ionicity of A-site ions, and thus increases energy storage property. As a result, the BNT-6BT-0.08SLT ceramic maintains a high P s value of 40.77 μC/cm3 and exhibits excellent energy storage performance (W = 1.76 J/cm3, η = 60.1%).

In-situ formed hierarchical transition metal oxide nanoarrays with rich antisite defects and oxygen vacancies for high-rate energy storage devices

Developing transition metal oxides (TMOs) with high energy, power, and long cycle lifetime for electric energy storage devices remains a critical challenge to date. Herein, we demonstrate a facile method that enables in-situ transformation of nickel cobalt oxide nanowire arrays (NiCoO NWA) into hierarchical nanowire-nanosheet arrays (ac-NiCoO NWSA) for enhanced energy storage properties. More specifically, the method leads to formation of atomically thin nanosheets (only 2.0 nm) and creates abundant antisite defects and oxygen vacancies. Owing to these merits, the as-prepared ac-NiCoO NWSA electrode exhibits over five-fold higher specific capacity, superior rate capability (up to 100 A/g), and excellent cycling stability of 10,000 cycles at 50 A/g in alkaline electrolyte compared to pristine NiCoO NWA. Density functional theory (DFT) simulations elucidate the electrochemical activity enhancement mechanism of the TMOs. Moreover, our method triggers similar structural reconstruction phenomenon on other TMOs including ZnCo-, CoMn- and ZnNiCo-oxides, proving the universality of the method. Our findings provide a general method towards simultaneously manipulating the micro-morphologies and defects of TMOs for advanced energy storage devices.

Enhanced energy storage properties of 0.7Bi0·5Na0·5TiO3-0.3SrTiO3 ceramic through the addition of NaNbO3

Relaxor ferroelectrics with high energy density and efficiency are good candidates for pulsed power devices. In the present work, (1-x) (0.7Bi0·5Na0·5TiO3-0.3SrTiO3)-xNaNbO3 (x = 0.0–0.10) [(1-x)(0.7BNT-0.3ST)-xNN] ceramics were prepared using conventional solid state reaction method. The typical relaxor ferroelectric behavior was found in all compositions. The transformation of the material from non-ergodic to an ergodic realxor ferroelectric phase with increasing NN content was revealed, which facilitated the enhanced recoverable energy (Wrec) and efficiency (ƞ). Specifically, 0.92(0.7BNT-0.3ST)-0.08NN ceramic showed a high value of Wrec ~2.49 J/cm3 with the ƞ ~ 85% at a low electric-field of 170 kV/cm and retained a small variation (±11%) in Wrec and the high ƞ (>84%) over a broad temperature range (0 °C–120 °C). The remarkable performance of 0.92(0.7BNT-0.3ST)-0.08NN ceramic making it promising for applications of low electric-field and temperature-stable energy storage capacitors.

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.

Enhanced energy storage properties at phase boundary in Fe‐doped Ba(Zr0.04Ti0.96)O3 ceramics with a slush polar state

Enhanced energy storage properties at phase boundary in Fe‐doped Ba(Zr0.04Ti0.96)O3 ceramics with a slush polar state

Significantly enhanced energy storage properties of Nd3+ doped AgNbO3 lead-free antiferroelectric ceramics

Lead-free dielectric capacitors for energy storage device have attracted increasing attention recently because of their high-power density and superior temperature stability. In this work, Nd-doped silver niobate (AgNbO3, abbreviated as AN) lead-free antiferroelectric ceramics were prepared by utilizing traditional solid state reaction method. A large energy storage density of 4.6 J/cm3 and an efficiency of 62.5% were simultaneously obtained in the 1% Nd-doped AN sample with an outstanding power density of 54.0 MW/cm3 and an ultrafast discharge speed (t0.9) of 59.2 ns. Additionally, the 1% Nd-doped AN ceramic demonstrates a good temperature stability from 25 ℃ to 130 ℃. The excellent energy storage properties of the 1% Nd-doped ceramic is ascribed to the enhanced breakdown electric field induced by grain size engineering and the construction of phase structure via heterovalent substitution at the A-site of the lattice structure at room temperature. Our present work suggests that the 1% Nd-doped AN ceramic show promise for energy storage application in miniaturized mobile electronic devices and high-power equipment.

Enhanced energy storage properties of lead-free NaNbO3-based ceramics via A/B-site substitution

Lead-free ceramic-based dielectric capacitors have attracted extensive investigation due to their potential applications in pulsed power devices. However, the main drawback of dielectric ceramics is the relatively low energy storage density. Herein, Bi3+ and Mg2+ with different ionic radius and valence are introduced into antiferroelectric NaNbO3 matrix to form (Na1-3/2xBi3/2x)(Nb1-xMgx)O3 solid solutions, where the antiferroelectric phase is stabilized and the relaxor behavior is also improved. Of particular importance is that a large breakdown strength (Eb) of 78.3 kV/mm, an ultrahigh recoverable energy density (Wrec) of 10.9 J/cm3 and efficiency (η) of 83% are simultaneously achieved in (Na0.91Bi0.09)(Nb0.94Mg0.06)O3 ceramic. Moreover, the energy storage properties of (Na0.91Bi0.09)(Nb0.94Mg0.06)O3 ceramic also reveals superior frequency (1–100 Hz), cycling (100–105) and thermal (30°C–100°C) stability, together with the ultrafast discharge rate (<25 ns). These results demonstrate the NaNbO3-based lead-free relaxor antiferroelectric ceramics is a promising candidate for energy storage application.

Enhanced energy storage properties in lead-free NaNbO3–Sr0.7Bi0.2TiO3–BaSnO3 ternary ceramic

The urgent requirement of environment-friendly materials with excellent energy storage performance for pulse power systems has sparked considerable research on lead-free ceramics. In this work, a new lead-free 0.90(0.80NaNbO3–0.20Sr0.7Bi0.2TiO3)–0.10BaSnO3 ceramic with high recoverable energy storage density (Wr = 3.51 J/cm3) and decent energy storage efficiency (η = 70.85%) has been obtained. In particular, these ceramics exhibit an ultrahigh breakdown strength of 402 kV/cm due to the dense microstructure and small grain size. The impedance analysis also reveals that the incorporation of BaSnO3 is conducive to the enhancement of insulation ability and breakdown strength. Additionally, great thermal stability (ΔWr < 10% over 20–120 °C at 200 kV/cm) and fatigue resistance (ΔWr < 1% after 120,000 electrical cycles at 200 kV/cm) are observed, indicating that the 0.90(0.80NaNbO3–0.20Sr0.7Bi0.2TiO3)–0.10BaSnO3 ceramics have promising application prospect for high-temperature energy storage devices in pulse power applications.

Enhanced energy storage properties achieved in Na0.5Bi0.5TiO3-based ceramics via composition design and domain engineering

Dielectric ceramic materials with high power density and fast charge–discharge speed have attracted increasing attention in recent years. However, their mutually restricted energy density and efficiency as well as unsatisfactory temperature stability have been the main obstacles for their practical applications. Herein, a high recoverable energy density of 5.02 J·cm−3 and a high efficiency of ~ 90% can be obtained under 422 kV·cm−1 in the Sr0.85Sm0.1TiO3 (SST)-modified Na0.5Bi0.5TiO3 (NBT) ceramics via composition design and domain engineering strategy, and the excellent stability of energy storage properties in frequency (1–100 Hz) and temperature (20–180 °C) were also observed at 250 kV·cm−1 in the 0.50NBT-0.50SST ceramics, which are attributed to the improved breakdown strength (Eb) and the enhanced relaxation behavior. The increased band gap width and refined grain size are responsible for the significantly enhanced Eb of Na0.5Bi0.5TiO3-based solid solution, being confirmed by ultraviolet and visible (UV–vis) absorption spectra as well as scanning electron microscopy. The generation of polar nanoregions as demonstrated by piezoresponse force microscopy and transmission electron microscopy results in a negligible remanent polarization and thermally stable polarization-field response. It is worth noting that the energy density will be further greatly optimized due to the improvement of Eb if this ceramic composite is made into multilayer ceramic capacitor as a dielectric layer. Moreover, a large power density of 188.6 MW·cm−3 and a fast discharge speed of 70 ns can also be achieved in the optimized composition. The results show that the multi-scale optimization strategy is an effective way to realize excellent comprehensive energy storage performances in the Na0.5Bi0.5TiO3 based ceramics.

Effects of Mn and Y co-doping on the energy storage properties of Ba0.67Sr0.33TiO3 films

Enhanced energy storage properties were observed in Ba0.67−xYxSr0.33Ti0.993Mn0.007O3 (BSTM-xY, x = 0, 0.003, 0.006 and 0.012) films prepared by radio frequency magnetron sputtering technique. All film samples present polycrystalline with perovskite structures, and compact microstructures with homogeneous grain size distribution were observed. The enhanced energy storage properties are attributed to the “slimmer” hysteresis loops and increased maximum polarization as the introduction of Y3+ ion. The energy storage density (W) and recoverable energy storage density (Wre) increase with increasing Y3+ contents. A large Wre ~ 17.8 J/cm3 accompanied by stable energy efficiency (η ~ 77%) for BSTM-0.012Y film was observed. The dielectric properties, tunability and leakage current density are enhanced by optimizing Y3+ doping contents.

Construction of 2D–2D Plate-on-Sheet Cobalt Sulfide–Reduced Graphene Oxide Nanocomposites for Enhanced Energy Storage Properties in Supercapacitors

Cobalt sulfides, as a class of promising electrode materials for supercapacitors, are still limited by an unsatisfactory rate capability and cyclic instability, which are caused by their easy agglo...

Enhanced energy storage property and dielectric breakdown strength in Li+ doped BaTiO3 ceramics

(Ba1-xLix)TiO3 ceramics (x = 0.01, 0.02, 0.04, 0.06, 0.08, 0.10; abbreviated as BLTx) were synthesized via traditional solid-state method, the microstructure, energy storage performance including the dielectric breakdown strength (BDS) and the process of charge transportation were investigated. All the ceramics exhibit pure tetragonal perovskite structure and the grain size of the ceramics was effectively refined by Li+ ions doping. The BDS increased from 39.2 kV/cm to 76.5 kV/cm greatly due to moderate oxygen vacancies. The optimum energy-storage density of 0.293 J/cm3 and energy-storage efficiency of 64.7% were obtained at x = 0.04 (BLT4). Meanwhile the remnant polarization and the maximum polarization of BLT4 ceramic were 3.8 µC/cm2 and 17.6 µC/cm2, respectively, indicating that the long-range ordered ferroelectric domains of BaTiO3 has been destroyed. The BLTx ceramics with enhanced energy-storage properties and excellent performance parameters are potential candidates for capacitors.

Enhanced energy storage properties of ZrO2-doped (Na0.5Bi0.5)0.4Sr0.6TiO3 Pb-free relaxor ferroelectric ceramics

(Na0.5Bi0.5)0.4Sr0.6Ti1-xZrxO3 relaxor ferroelectric ceramic were prepared by a traditional ceramic preparation process introducing Zr4+ at the B-site. It was observed that introducing an appropriate amount of Zr4+ ions into the NBST matrix can improve the energy storage efficiency. (Na0.5Bi0.5)0.4Sr0.6Ti0.5Zr0.5O3 shows excellent energy storage density up to 2.83 J/cm3, and excellent efficiency (83.90 %) at 220 kV/cm. A single layer ceramic capacitor (SLCC) was also prepared by the tape casting technique for multilayer ceramic capacitors (MLCCs) to further enhance the energy storage performance. The recoverable energy storage capacity is increased to 4.52 J/cm3 and the efficiency is 70.02 % at 460 kV/cm. Moreover, it still has a relatively stable energy storage performance after 105 cycles of charge and discharge. This sample has exhibited outstanding energy storage performance, fatigue resistance, and charge/discharge performance and has great potential value in practical applications.

Energy Storage Properties of Mn and Y Codoped Ba0.67Sr0.33TiO3 Ceramics

Ba0.67‐xYxSr0.33Ti0.995Mn0.005O3 (BSTM‐xY, x = 0, 0.003, 0.006, and 0.012) ceramics are synthesized by citrate sol–gel methods and the effect of Y contents on the energy storage properties of BSTM‐xY ceramics is investigated. Dense microstructures with fine grain are observed as Mn and Y codoping. The introduction of Y enhances the dielectric properties and leakage current density of BSTM‐xY ceramics. Mn and Y codoped BST ceramics show enhanced energy storage properties due to the improved microstructure and “slimmer” hysteresis loops with high polarization. The energy efficiency presents good thermal stability and electric field stability as Y doping. The energy density of BSTM‐0.012Y ceramic is about 4 times larger than BSTM ceramic. The energy efficiency of BSTM‐0.012Y ceramic maintains at about 91% at the field range of 30–150 kV cm−1 and at the temperature range of 20–50 °C.

Enhanced energy storage properties of thermostable sandwich-structured BaTiO3/polyimide nanocomposites with better controlled interfaces

The energy density of polymers for high temperature applications is still relatively low. Among them, polyimide (PI) is one of the most attractive matrixes because of its high thermal stability. Instead of the mono thermal imidization method to fabricate multilayer PI nanocomposites in the literature, a novel method was proposed herein to better control the multilayer morphology, which could help to further enhance the energy storage properties. The method's effect on the morphology especially on the interfaces between adjacent layers was studied, and then the mechanism of breakdown strength change was discussed by a proposed model based on bipolar charge transport. The sandwich-structured PI nanocomposites, composed of the middle polarization layer with high BaTiO3 (BT) content and the two outer insulation layers with low BT content, were fabricated. Enhanced breakdown field and discharged energy density of 550 kV/mm and 5.1 J/cm3 with the efficiency of about 70% were achieved, while keeping a high thermal stability (500 kV/mm and 3.9 J/cm3 at 100 °C). This work presents a promising polymer nanocomposite for energy storage capacitors especially in extreme temperature environments, and a new concept to fabricate multilayer dielectric composites.

Enhanced energy storage properties and temperature stability of fatigue-free La-modified PbZrO3 films under low electric fields

Electrostatic energy-storage capacitors, with their ultrahigh storage density and high temperature stability, have been receiving increasing attention of late for their ability to meet the critical requirements of pulsed power devices in low-consumption systems. In such a context, this work reports on the successful production of anti-ferroelectric (AFE) thin films with excellent energy storage performance under a relatively low electric field. In particular, La-doped PbZrO3 thin films were fabricated using a sol-gel method, yielding a recoverable energy storage density of 34.87 J cm−3 with an efficiency of 59.23% at room temperature under the electric field of ∼800 kV cm−1. The temperature dependence of the energy storage property was demonstrated from room temperature to 210°C, indicating a stable density variation between 34.87 and 27.98 J cm−3. The films also exhibited excellent anti-fatigue property (endurance of up to 3×109 cycles and the recoverable energy storage density varied from 39.78 to 29.32 J cm−3 combined with an efficiency of 61.03%`-44.95% under the test frequencies from 10 to 5000 Hz). All results were obtained using compact films with a high polarization (Pmax) of approximately 103.7 µC cm−2 and low remnant polarization (Pr∼7 µC cm−2), which was owing to the combination of LaNiO3 buffer layers and vacancies at Pb sites. These results illustrate the great potential of pulsed power devices in low-consumption systems operating in a wide range of temperatures and long-term operations.