High Energy Storage Efficiency Research Articles

Facile synthesize of PANI/GO/CuFe2O4 nanocomposite material with synergistic effect for superb performance supercapacitor

Storage of energy and the pollution of the environment are two of the world's primary challenges currently. As a consequence of the diminishing supply of fossil fuels, renewable energy production has become of great significance. As a result of the high energy/power density and extended life cycle of hybrid supercapacitors, these have recently attracted the attention of energy experts. As new hybrid supercapacitor electrodes, a straightforward two-step technique was developed and constructed a ternary PANI/GO/CuFe2O4 nanocomposite. The copper ferrite (CuFe2O4) nanoparticles were disseminated on graphene oxide (GO) sheets, utilizing a hydrothermal approach, followed by an in situ polymerization procedure for a coating with polyaniline (PANI). Various electrochemical techniques were utilized to evaluate the instances' electrochemical characteristics, and the ternary system's linked topology enabled an array of electrochemical characterizations.In comparison to studies of single and binary samples, the ternary PANI/GO/CuFe2O4 electrode had the highest specific capacitance (SC) of 614.76 F/g at 1 A/g and the best cycle stability (remaining at 88% after 3,500 cycles) while exhibiting the lowest resistance in electrochemical impedance spectroscopy. A constructed asymmetric supercapacitor that utilized hybrid PANI/GO/CuFe2O4//GO electrodes indicated an SC of 124 F/g at 1 A/g. The asymmetric supercapacitor provided 49.72 Wh/kg and 923 W/kg energy density and specific power, respectively. These findings indicate that the ternary PANI/GO/CuFe2O4 composite material has the capability to be employed as unique electrode material in supercapacitor applications to produce high-efficiency and reliable energy storage devices.

Improvement of Energy Storage Properties of NaNbO3-Based Ceramics through a Relaxation Strategy

NaNbO3 (NN) is a widely studied antiferroelectric ceramics in recent years. However, NN ceramics always exhibit a square P-E loop with larger P r, originating form an irreversible antiferroelectric-ferroelectric (AFE-FE) phase transition under an applied electric field and limit the further development. In this paper, a novel lead-free relaxor ferroelectric ceramic, (1−x)NaNbO3-x(0.5Bi0.5Na0.5TiO3−0.5Ba0.3Sr0.7TiO3) [(1−x)NN-xBNBST, x = 0, 0.10, 0.15, 0.20, 0.25, 0.30], was designed and prepared via a local random field relaxation strategy. Dielectric testing show that the addition of BNBST significantly improved the relaxor behavior of the NN, which is effective for enhancing the W rec and η of NN-based ceramics. When x = 0.2, the ceramic obtains a high recoverable energy storage density (W rec = 2.024 J cm−3) and energy storage efficiency (η = 63%) at a low electric field of 130 kV cm−1. Meanwhile, the polarization-electric field (P-E) hysteresis loops and charge-discharge results of the sample with x = 0.2 at different temperatures and frequencies show that it is a prospective material for pulsed energy storage capacitors.

Microstructure-driven excellent energy storage NaNbO3-based lead-free ceramics

Alkali niobate-based energy storage ceramics have recently drawn considerable attention because of their ultrahigh recoverable energy storage density (W rec ) and environment-friendly feature. However, it is still quite challenging for them to maintain a high energy storage efficiency (η). Herein, spark plasma sintering (SPS) technique was adopted to tailor the microstructure of Na 0.7 Bi 0.1 Nb 0.9 Ta 0.1 O 3 lead-free ceramics. Compared with their conventional sintered counterparts, the samples sintered by SPS exhibit more homogeneous microstructure, finer grains, decreased porosity and fewer oxygen vacancies. Consequently, a high breakdown strength, small remanent polarization and low polarization hysteresis give rise to excellent comprehensive energy storage performance (W rec = 6.68 J/cm 3 , η = 90.5%) of the SPS sintered ceramics. This work not only provides a potential lead-free energy storage ceramic system, but also reveals the remarkable role of the tailored microstructure in improving energy storage properties.

Carnot battery system integrated with low-grade waste heat recovery: Toward high energy storage efficiency

The low-grade waste heat is widely distributed in various scenarios and lacks suitable technologies for recovery. Carnot battery is a large-scale electrical energy storage technology, and pumped thermal energy storage (PTES) is one of the branches in which the waste heat can be efficiently utilized. The integration of the PTES system and waste heat promotes energy storage efficiency and tackles the problem of low-grade waste heat utilization. Aiming to improve the energy storage efficiency of the system, several PTES systems have been put forward, where the system configurations were modified and the waste heat is employed in both the heat pump cycle and the organic Rankine cycle. The novel concept of the PTES systems was examined, and the energy-conservation mechanism was further explored. Moreover, the effect of the heat storage temperature pair on the PTES system was evaluated, and the results indicate that the highest efficiency can attain when the low heat storage temperature is around 100.0 °C. The implementation of different working fluids in the charging and discharging process leads to the promotion of power-to-power efficiency, and the efficiency increases from 65.56 % to 66.52 % when the high heat storage temperature is chosen as 130 °C. In terms of various waste heat parameters, the power-to-power efficiency of the advanced PTES system can attain 99.3 % as the inlet temperature of the waste heat rises to 90.0 °C.

High Energy Storage Density in Nd(Zn2/3Nb1/3)O3‐Doped BiFeO3–BaTiO3 Ceramics

AbstractLead‐free ceramics with high recoverable energy density (Wrec) and energy storage efficiency (η) are attractive for advanced pulsed power capacitors to enable greater miniaturization and integration. In this work, a series of perovskite structured (1‐x)(Bi0.6Ba0.4)(Fe0.6Ti0.4)O3−xNd(Zn2/3Nb1/3)O3 (BF‐BT‐NZN) ceramics with high energy storage density through the solid‐state reaction method are successfully prepared, and the breakdown strength (Eb) and energy storage density are further improved by a membrane rolling process. The highest energy densities of the 0.94(BF‐BT)−0.06NZN ceramics are Wrec ≈ 5.6 J cm−3 and η ≈ 82.9%, which are due to the enhanced breakdown field intensity (BDS ≈ 400 kV cm−1) and the maximum polarization (Pmax≈ 38 µC cm−2). These results indicate that (1−x)(Bi0.6Ba0.4) (Fe0.6Ti0.4)O3−xNd(Zn2/3Nb1/3)O3 ceramics are high‐efficiency lead‐free materials for potential application in high‐energy‐storage capacitors.

4D printing of MXene hydrogels for high-efficiency pseudocapacitive energy storage

2D material hydrogels have recently sparked tremendous interest owing to their potential in diverse applications. However, research on the emerging 2D MXene hydrogels is still in its infancy. Herein, we show a universal 4D printing technology for manufacturing MXene hydrogels with customizable geometries, which suits a family of MXenes such as Nb2CTx, Ti3C2Tx, and Mo2Ti2C3Tx. The obtained MXene hydrogels offer 3D porous architectures, large specific surface areas, high electrical conductivities, and satisfying mechanical properties. Consequently, ultrahigh capacitance (3.32 F cm−2 (10 mV s−1) and 233 F g−1 (10 V s−1)) and mass loading/thickness-independent rate capabilities are achieved. The further 4D-printed Ti3C2Tx hydrogel micro-supercapacitors showcase great low-temperature tolerance (down to –20 °C) and deliver high energy and power densities up to 93 μWh cm−2 and 7 mW cm−2, respectively, surpassing most state-of-the-art devices. This work brings new insights into MXene hydrogel manufacturing and expands the range of their potential applications.

Optimal configuration of improved integrated energy system based on stepped carbon penalty response and improved power to gas

The high construction cost and low energy storage efficiency of P2G devices in integrated energy systems limit their performance in energy storage. The heat generated by P2G during the reaction is usually neglected, and reasonable consideration and utilization of this heat can significantly improve the energy storage performance of P2G. At the same time, the establishment of the carbon market has caused a conflict between carbon capture and profitability. How enterprises can achieve a green economy transition is an urgent issue to be addressed. In this paper, an operational strategy of carbon capture device based on stepped carbon penalty response (SCPR) is proposed to solve the economical carbon capture and applied in an improved integrated energy system (IIES). The IIES improves the thermal utilization of P2G and enhances the energy coupling of this energy with carbon capture device. Finally, an improved honey badger algorithm(IHBA) is used to solve the optimal configuration of the case. Results show that the annual performance of the IIES is optimized by 26.43% compared to the separate production system. Compared to conventional integrated energy systems, IIES reduces CO2 emissions while lowering annual operating costs. IHBA outperforms other comparative algorithms in terms of overall performance.

Interlayer Coupling Enhanced Energy Storage Performance in a Flexible BMT-BTO/BMT Multilayer Ferroelectric Film Capacitor

Flexible ferroelectric capacitors with high energy density and storage efficiency are highly desirable in the next generation of flexible electronic devices. To develop high-performance ferroelectric capacitors, a conventional approach is chemical modification. Here, a novel approach of interlayer coupling is proposed to achieve high energy storage performance in BiMg0.5Ti0.5O3-BaTiO3/BiMg0.5Ti0.5O3 (BMT-BTO/BMT)N multilayer ferroelectric films fabricated on flexible mica substrates via a sol-gel coating method. The interlayer electrostatic coupling between the ferroelectric BMT and relaxor ferroelectric BMT-BTO layers leads to small remnant polarization and large breakdown field strength, resulting in an outstanding energy storage density of ∼106.8 J cm-3 and a good efficiency of ∼75.6% in the multilayer thin films. Further, the energy storage performance remains stable in a wide range of temperatures (25-200 °C) and frequencies (500 Hz to 10 kHz) after 108 electrical loading cycles. The energy storage performance also has no obvious deterioration when the multilayer film experiences 104 mechanical bending cycles with a bending radius of 4 mm. The approach proposed in the present work should be generally implementable in other multilayer flexible ferroelectric capacitors and offers a novel avenue to enhance energy storage performance by tuning the interlayer coupling.

Achieving high energy storage density simultaneously with large efficiency and excellent thermal stability by defect dipole, and microstructural engineering in modified-BaTiO3 ceramics

The electric energy produced from renewable sources can assist in shifting to clean energy. An efficient energy storage system is needed to use this energy for an appropriate time. High breakdown strength (Eb) and a significant difference between (Pmax) and (Pr) are required to achieve this goal. Here double-hysteresis-loop ceramics with different polarization are achieved by B-site co-doping engineering to control the defect structure. According to the structural analysis, the (Ni2+, Cu2+), (Mg2+, Cu2+), and (Mg2+, Ni2+) co-dopant ions were successfully incorporated into the BTO unit cell. Results show that the sample co-doped with Mg2+ and Ni2+ exhibits the apparent characteristics of a double hysteresis loop, higher polarization, and more considerable breakdown strength (Eb). This behavior was explained based on the defective dipoles' formation. Low valence (Ni2+, Cu2+), (Mg2+, Cu2+), and (Mg2+, Ni2+) ions co-substitute Ti4+ ions to form (MTi′′−VO••)×; [M= Mg2+, Cu2+, Ni2+] defect dipoles with neighbouring oxygen vacancies. The domain wall was pinned by the defect dipoles and prevented from moving by the oxygen vacancies, resulting in a pinched hysteresis loop that resembles the double hysteresis loop found in antiferroelectric materials. A high energy storage density and efficiency are thereby produced. At an electric field of 159 kV/cm, the BMNT sample displayed an energy storage density (Wrec) of 1.585 J/cm3, which was around 6 times more than that of the pure sample, and an efficiency (η) of about 94%. The BMNT sample is also exceptionally stable over a range of temperatures and frequencies, making them a good candidate for applications in the field of energy storage in the future.

Novel 3D thermal energy storage materials based on highly porous patterned printed clay supports infiltrated with molten nitrate salts

One of the main drawbacks of phase change materials (PCM) to be employed as thermal energy storage (TES) systems in energy applications, such as concentrated solar power (CSP), is the liquid leakage, which considerably reduces the storage efficiency. To overcome this issue, a novel approach is presented, which is based on the development of three-dimensional (3D) engineered TES structures (3DTES) formed by highly porous patterned 3D printed low-cost clay supports (up to ~85% of total porosity) that are infiltrated with a molten sodium nitrate salt. Expanded vermiculite supports are additive manufactured by robocasting, a direct ink writing technology, using clay aqueous inks with a pseudoplastic behavior. 3DTES are lightweight (~1.8 g·cm −3 ), easy to handle, mechanically robust (~68 MPa) and exhibit high PCM encapsulation capacity (~78%), avoiding the molten salt leakage. Furthermore, they present an enthalpy of fusion of ~136 J·g −1 , excellent thermal stability, and high thermal energy storage efficiency (~80%) and thermal conductivity (1.27 W·m −1 ·K −1 ), which is indicative of a great charging-discharging ability. The results open new opportunities through the 3DTES approach to manufacture promising affordable materials with outstanding performance for CSP applications. • Novel 3D engineered thermal energy storage structures (3DTES) are manufactured. • Highly porous 3D printed patterned clay supports are infiltrated with a molten salt. • 3DTES are light, easy to handle, robust and avoid the molten salt leakage. • 3DTES exhibit excellent efficiency, thermal stability and high thermal conductivity. • 3DTES are promising affordable materials with outstanding performance for CSP.

Applications of Carbon Dots in Electrochemical Energy Storage

As one kind of carbon nanomaterials, since their discovery at the beginning of the century, carbon dots (CDs) have been attracting extensive attention in sensing, bioimaging, catalysis, organic light-emitting diodes, etc. due to their rich and diverse physical and chemical properties. Although the precise structures of CDs need to be further analyzed and elaborated, it is confirmed that there are many functional groups on the surfaces including amino, hydroxyl, carboxyl and thiol, depending on the precursors and preparation processes used. The crystalline/amorphous conjugated graphite-like sp2 domains and segments inside the CDs provide good electrical conductivity and photoelectric conversion capability. The applications of CDs in electrochemical energy storage have been carried out extensively and become a hot topic in recent years. In this review, the recent progress about the applications of CDs in typical electrochemical energy storage devices including supercapacitors, lithium-ion batteries, sodium-ion batteries and potassium-ion batteries is outlined and summarized. The relationships between material structures and device performances are mainly analyzed. Finally, it is anticipated that the development of CDs can continuously boost the study of high-efficiency energy storage devices profoundly.

Interfacial 2D Montmorillonite Nanocoatings Enable Sandwiched Polymer Nanocomposites to Exhibit Ultrahigh Capacitive Energy Storage Performance at Elevated Temperatures.

Polymer dielectrics are essential for advanced electrical and electronic power systems due to their ultrafast charge-discharge rate. However, a long-standing challenge is to maintain their dielectric performance at high temperatures. Here, a layered barium titanate/polyamideimide nanocomposite reinforced with rationally designed interfaces is reported for high-temperature high-energy-density dielectrics. Nanocoatings composed of 2D montmorillonite nanosheets with anisotropic conductivities are interposed at two kinds of macroscopic interfaces: 1) the interfaces between adjacent layers in the nanocomposites (inside) and 2) the interfaces between the surface of the nanocomposite and the electrode (outside). By revealing the charge transport behavior with Kelvin probe force microscope, surface potential decay, and finite element simulation, it is demonstrated that the outside nanocoatings are observed to diminish charge injection from the electrode, while the inside nanocoatings can suppress the kinetic energy of hot carriers by redirecting their transport. In this interface-reinforced nanocomposite, an ultrahigh energy density of 2.48 J cm-3 , as well as a remarkable charge-discharge efficiency >80%, is achieved at 200°C, six times higher than that of the nanocomposite without interfacial nanocoatings. This research unveils a novel approach for the structural design of polymer nanocomposites based on engineered interfaces to achieve high-efficient and high-temperature capacitive energy storage.

Enhancement of recoverable energy density and efficiency of K0.5Na0.5NbO3 ceramic modified by Bi(Mg0.5Zr0.5)O3

As one of the most popular lead-free energy storage materials, K0.5Na0.5NbO3 (KNN)-based ceramics are expected to replace lead-based ceramics due to their high dielectric constant, high Curie temperature, and environmental friendliness. However, the high remnant polarization (Pr) and low breakdown strength (BDS) of KNN ceramic lead to its low energy storage properties, which limits its applications in energy storage field. In this work, the energy storage properties of KNN ceramic were improved by reducing average grain size and enhancing relaxor behavior. The 0.85K0.5Na0.5NbO3-0.15Bi(Mg0.5Zr0.5)O3 (0.85KNN-0.15BMZ) ceramic prepared by the solid state method not only has high recoverable energy storage density value (Wrec) of 3.47 J cm-3 but also has high energy storage efficiency value (η) of 89.14% at a high applied electric field of 320 kV/cm. In addition, the Wrec and η of 0.85KNN-0.15BMZ ceramic fluctuate slightly over the whole temperature range of 20–120 °C at 200 kV/cm, showing excellent temperature stability. At the same time, it can be concluded by first-order reversal curve distribution that 0.85KNN-0.15BMZ ceramic has excellent energy storage properties due to their enhanced relaxor behavior. In summary, the 0.85KNN-0.15BMZ ceramic can be used as the novel dielectric capacitor materials.

Fabrication of a lead-free ternary ceramic system for high energy storage applications in dielectric capacitors.

The importance of electroceramics is well-recognized in applications of high energy storage density of dielectric ceramic capacitors. Despite the excellent properties, lead-free alternatives are highly desirous owing to their environmental friendliness for energy storage applications. Herein, we provide a facile synthesis of lead-free ferroelectric ceramic perovskite material demonstrating enhanced energy storage density. The ceramic material with a series of composition (1-z) (0.94Na0.5Bi0.5TiO3-0.06BaTiO3)-zNd0.33NbO3, denoted as NBT-BT-zNN, where, z = 0.00, 0.02, 0.04, 0.06, and 0.08 are synthesized by the conventional solid-state mix oxide route. Microphases, microstructures, and energy storage characteristics of the as-synthesized ceramic compositions were determined by advanced ceramic techniques. Powder X-ray diffraction analysis reveals pure single perovskite phases for z = 0 and 0.02, and secondary phases of Bi2Ti2O7 appeared for z = 0.04 and 0.08. Furthermore, scanning electron microscopy analysis demonstrates packed-shaped microstructures with a reduced grain size for these ceramic compositions. The coercive field (Ec) and remnant polarization (Pr) deduced from polarization vs. electric field hysteresis loops determined using an LCR meter demonstrate decreasing trends with the increasing z content for each composition. Consequently, the maximum energy storage density of 3.2J/cm3, the recoverable stored energy of 2.01J/cm3, and the efficiency of 62.5% were obtained for the z content of 2mol% at an applied electric field of 250kV/cm. This work demonstrates important development in ceramic perovskite for high power energy storage density and efficiency in dielectric capacitors in high-temperature environments. The aforementioned method makes it feasible to modify a binary ceramic composition into a ternary system with highly enhanced energy storage characteristics by incorporating rare earth metals with transition metal oxides in appropriate proportions.

(Digital Presentation) Electrochemical Behavior of Ionic Liquid Modified of Lithium Bis(fluorosulfonyl)Imide Based Electrolyte for Lithium-Ion Batteries

The high efficient energy storage, lithium-ion batteries (LIBs) is accounted as one of the most important storage devices to facilitate the transition of renewable energy conversion. The electrolyte component is the most important in deciding the capacity of LIBs. Lithium bis(fluorosulfonyl)imide (LiFSI) is recently considered as promising conducting electrolyte salt for LIBs because it shows enabling high voltage, high energy density, long cycle life, and accelerates the fast-charging Li-ion batteries. Generally, Additionally, LiFSI and LiPF6 based electrolyte are used in the most of commercial LIBs. Last few years, LiFSI is regarded as an alternative electrolyte to the classical LiFP6 due to its high ionic conductivity, good thermal stability, and HF free nature. In this work, the controlled mixing of ionic liquids (ILs) (imidazolium salts and pyridinium salts) in LiFSI electrolyte was carried out to enhance the ionic conductivity, thermal stability, viscosity, and solubility in organic solvents. The ILs modified LiFSI electrolyte was prepared by adding a constant 1.0 M LiFSI and varying the concentration of ILs from 5 to 20% volume in trimethyl phosphate (TMP). After the modification by ILs, the ionic conductivity of LiFSI electrolyte (10.623 mS/cm) was considerably increased as compared to LiFSI only. The flammability test of electrolyte revealed that ILs modified LiFSI electrolyte was non-flammable, indicating excellent stability in any circumstances. The prepared ILs modified LiFSI electrolyte was used to fabricate coin cell LIBs using double-coated side electrodes (both CMS graphite/Li-NCM (5:2:3) and CMS graphite/LiFePO4). From GCD analysis, the fabricated LIBs with ILs modified LiFSI electrolyte showed a significant improvement in the charging/discharging ability as compared to commercial LIBs with LiPF6 electrolyte. This study manifests that the modification of LiFSI by novel ILs would be promising to achieve highly efficient liquid electrolytes for high performance LIBs.

Thermal performance analysis of a 20-feet latent cold energy storage device integrated with a novel fin-plate unit for building cooling

A 20-feet latent cold energy storage device integrated with a novel fin-plate unit was used to cool a 400 m2 building space, in which the cold energy could be generated from renewable energy, industrial waste cold, or off-peak electricity. Due to the low thermal conductivity of n-pentadecane, a novel fin-plate unit was designed to improve the heat transfer rate of PCMs especially for the restricted charging process. Meanwhile, energy storage efficiency of the device under different operating parameters was analyzed. The results showed that the introduction of straight fin significantly accelerated the solidification process of encapsulated PCMs. Compared with straight fin, the branch fin (lBranch = 30 mm, α = 120°) that had the same volume was found to shorten 27.7% of the charging time. While such branch fin could only shorten 2.8% of the discharging time, which might be attributed to the balance between the contribution and the restrictiveness for heat transfer caused by the fin. The small inlet velocity of 0.03 m/s was shown to contribute to a high energy storage efficiency of 86.83% and a long output time of 12.08 h. The results of this work were expected to provide the foundation for building the low-carbon architecture.

Composing atomic transition metal sites for high-performance bifunctional oxygen electrocatalysis in rechargeable zinc–air batteries

Rechargeable zinc–air batteries have attracted extensive attention as clean, safe, and high-efficient energy storage devices. However, the oxygen redox reactions at cathode are highly sluggish in kinetics and severely limit the actual battery performance. Atomic transition metal sites demonstrate high electrocatalytic activity towards respective oxygen reduction and evolution, while high bifunctional electrocatalytic activity is seldomly achieved. Herein a strategy of composing atomic transition metal sites is proposed to fabricate high active bifunctional oxygen electrocatalysts and high-performance rechargeable zinc–air batteries. Concretely, atomic Fe and Ni sites are composed based on their respective high electrocatalytic activity on oxygen reduction and evolution. The composite electrocatalyst demonstrates high bifunctional electrocatalytic activity (ΔE = 0.72 V) and exceeds noble-metal-based Pt/C + Ir/C (ΔE = 0.79 V). Accordingly, rechargeable zinc–air batteries with the composite electrocatalyst realize over 100 stable cycles at 25 mA cm−2. This work affords an effective strategy to fabricate bifunctional oxygen electrocatalysts for high-performance rechargeable zinc–air batteries.

Nanocellulose/two dimensional nanomaterials composites for advanced supercapacitor electrodes.

With the emerging of the problems of environmental pollution and energy crisis, the development of high-efficiency energy storage technology and green renewable energy is imminent. Supercapacitors have drawn great attention in wearable electronics because of their good performance and portability. Electrodes are the key to fabricate high-performance supercapacitors with good electrochemical properties and flexibility. As a biomass based derived material, nanocellulose has potential application prospects in supercapacitor electrode materials due to its biodegradability, high mechanical strength, strong chemical reactivity, and good mechanical flexibility. In this review, the research progress of nanocellulose/two dimensional nanomaterials composites is summarized for supercapacitors in recent years. First, nanocellulose/MXene composites for supercapacitors are reviewed. Then, nanocellulose/graphene composites for supercapacitors are comprehensively elaborated. Finally, we also introduce the current challenges and development potential of nanocellulose/two dimensional nanomaterials composites in supercapacitors.

High energy storage efficiency and temperature stability realized in the Ba0.3Sr0.7Zr0.18Ti0.82O3/LaNiO3 heterostructure thin films directly deposited on the conductive Si substrate

A high-performance energy storage capacitor would not display high energy storage density (Ue) but high energy storage efficiency (η). However, during raising the electric field (E) or temperature (T), the η in dielectric thin films often shows an obvious degradation process. The degradation process is closely related to the change of the charge carrier transport mechanism as a function of E or T. Compared with the electric breakdown strength, the relationship between η and the charge carrier transport mechanisms in the dielectric thin films was less concerning. In this work, by increasing the trigger E and T of the space charge limited current mechanism, the beginning of the η degradation process was delayed into higher E and T. Consequently, a high Ue (∼56.6 J/cm3) and η (∼93.9%) were achieved simultaneously in Ba0.3Sr0.7Zr0.18Ti0.82O3/LaNiO3 heterostructure thin films directly deposited on low-cost conductive silicon wafers. Moreover, the temperature stability was greatly improved. This result would also offer a promising approach to improve the electrical properties of the dielectric oxide thin films in a harsh environment of high temperatures by redistributing oxygen vacancies through the heterostructure interface.

Ultrahigh Energy Storage Density in Glassy Ferroelectric Thin Films under Low Electric Field.

The current approach to achieving superior energy storage density in dielectrics is to increase their breakdown strength, which often incurs heat generation and unexpected insulation failures, greatly deteriorating the stability and lifetime of devices. Here, a strategy is proposed for enhancing recoverable energy storage density(Wr ) while maintaining a high energy storage efficiency (η) in glassy ferroelectrics by creating super tetragonal (super-T) nanostructures around morphotropic phase boundary (MPB) rather than exploiting the intensely strong electric fields. Accordingly, a giant Wr of ≈86 J cm-3 concomitant with a high η of ≈81% is acquired under a moderate electric field (1.7 MV cm-1 ) in thin films having MPB composition, namely, 0.94(Bi, Na)TiO3 -0.06BaTiO3 (BNBT), where the local super-T polar clusters (tetragonality ≈1.25) are stabilized by interphase strain. To the knowledge of the authors, the Wr of the engineered BNBT thin films represents a new record among all the oxide perovskites under a similar strength of electric field to date. The phase field simulation results ascertain that the improved Wr is attributed to the local strain heterogeneity and the large spontaneous polarization primarily is originated from the super-T polar clusters. The findings in this work present a genuine opportunity to develop ultrahigh-energy-density thin-film capacitors for low-electric-field-driven nano/microelectronics.