Dielectric ceramics are highly desired for electronic systems owing to their fast discharge speed and excellent fatigue resistance. However, the low energy density resulting from the low breakdown electric field leads to inferior volumetric efficiency, which is the main challenge for practical applications of dielectric ceramics. Here, we propose a strategy to increase the breakdown electric field and thus enhance the energy storage density of polycrystalline ceramics by controlling grain orientation. We fabricated high-quality -textured Na0.5Bi0.5TiO3–Sr0.7Bi0.2TiO3 (NBT-SBT) ceramics, in which the strain induced by the electric field is substantially lowered, leading to a reduced failure probability and improved Weibull breakdown strength, on the order of 103 MV m−1, an ~65% enhancement compared to their randomly oriented counterparts. The recoverable energy density of -textured NBT-SBT multilayer ceramics is up to 21.5 J cm−3, outperforming state-of-the-art dielectric ceramics. The present research offers a route for designing dielectric ceramics with enhanced breakdown strength, which is expected to benefit a wide range of applications of dielectric ceramics for which high breakdown strength is required, such as high-voltage capacitors and electrocaloric solid-state cooling devices. The energy density of dielectric ceramic capacitors is limited by low breakdown fields. Here, by considering the anisotropy of electrostriction in perovskites, it is shown that -textured Na0.5Bi0.5TiO3–Sr0.7Bi0.2TiO3 ceramics can sustain higher electrical fields and achieve an energy density of 21.5 J cm−3.

Grain-orientation-engineered multilayer ceramic capacitors for energy storage applications.

Compared with fuel cells and electrochemical capacitors, dielectric capacitors are regarded as promising devices to store electrical energy for pulsed power systems due to their fast charge/discharge rates and ultrahigh power density. Dielectric materials are core components of dielectric capacitors and directly determine their performance. Over the past decade, extensive efforts have been devoted to develop high-performance dielectric materials for electrical energy storage applications and great progress has been achieved. Here, we present an overview on the current state-of-the-art lead-free bulk ceramics for electrical energy storage applications, including SrTiO3, CaTiO3, BaTiO3, (Bi0.5Na0.5)TiO3, (K0.5Na0.5)NbO3, BiFeO3, AgNbO3 and NaNbO3-based ceramics. This review starts with a brief introduction of the research background, the development history and the basic fundamentals of dielectric materials for energy storage applications as well as the universal strategies to optimize their energy storage performance. Emphases are placed on the design strategies for each type of dielectric ceramic based on their special physical properties with a summary of their respective advantages and disadvantages. Challenges along with future prospects are presented at the end of this review. This review will not only accelerate the exploration of higher performance lead-free dielectric materials, but also provides a deeper understanding of the relationship among chemical composition, physical properties and energy storage performance.

High-performance lead-free bulk ceramics for electrical energy storage applications: design strategies and challenges

Relaxor ferroelectric (FE) ceramic capacitors have attracted increasing attention for their excellent energy-storage performance. However, it is extremely difficult to achieve desirable comprehensive energy-storage features required for industrial applications. In this work, very high recoverable energy density W-rec approximate to 8.73 J cm(-3), high efficiency eta approximate to 80.1%, ultrafast discharge rate of

NaNbO3-(Bi0.5Li0.5)TiO3 Lead-Free Relaxor Ferroelectric Capacitors with Superior Energy-Storage Performances via Multiple Synergistic Design

Energy storage performance of BaTiO3-based relaxor ferroelectric ceramics prepared through a two-step process

Energy storage properties of bismuth ferrite based ternary relaxor ferroelectric ceramics through a viscous polymer process

Currently, bismuth-based perovskite-type ceramics are considered as promising species in energy storage applications because of easy phase- and micro/macro-structure modulations and high performances. In this work, the composition dependent phase structure and ferroelectric properties of novel Bi0.5K0.5TiO3–Ba(Mg1/3Nb2/3)O3 (BKT–BMN) ceramics are studied. Relaxor properties are gradually enhanced with increasing BMN content. The BKT–0.15BMN composition is selected to further explore energy storage performance via the hot-pressing (HP) technique. The results show that the recoverable energy storage density (WR = 3.14 J cm−3) for the HP sample is more than two times larger than that of the conventional sintering (CS) one. The outstanding WR also exhibits super stability against temperature and frequency variations. Besides, the energy storage efficiency (η) is up to 83.7% for the HP sample. In particular, the stored energy can be released in a very short time of ∼0.12 μs at room temperature, indicating a fast discharging speed for the HP sample. The enhanced performance is due to the decrease of grain size and the increase of grain boundaries, the mechanism underlying the microstructure effect on the breakdown strength (BDS) value is disclosed by numerical simulations (COMSOL). This work not only enriches the bismuth-based ceramic systems in pulsed power applications, but also deepens the understanding of the intrinsic mechanism of a refined microstructure that boosts energy storage performance.

Fine-grain induced outstanding energy storage performance in novel Bi0.5K0.5TiO3–Ba(Mg1/3Nb2/3)O3 ceramics via a hot-pressing strategy

Energy storage performance of Na0.5Bi0.5TiO3-SrTiO3 lead-free relaxors modified by AgNb0.85Ta0.15O3

Outstanding Energy Storage Performance of Na0.5Bi0.5TiO3-BaTiO3-(Sr0.85Bi0.1)(Mg1/3Nb2/3)O3 Lead-Free Ceramics

Nanomaterials of TiO2, (K0.5Na0.5)NbO3, and the TiO2/(K0.5Na0.5)NbO3 nanocomposite were successfully synthesized by a hydrothermal method. Impedance-type humidity sensors were fabricated based on t...

TiO2/(K,Na)NbO3 Nanocomposite for Boosting Humidity-Sensing Performances.

Supercritical relaxor nanograined ferroelectrics are demonstrated for high‐performance dielectric capacitors, showing record‐high overall properties of energy density ≈13.1 J cm−3 and field‐insensitive efficiency ≈90% at ≈74 kV mm−1 and superior charge–discharge performances of high power density ≈700 MW cm−3, high discharge energy density ≈6.67 J cm−3, and ultrashort discharge time <40 ns at 55 kV mm−1. Ex/in situ transmission electron microscopy, Raman spectroscopy, and synchrotron X‐ray diffraction provide clear evidence of the supercritical behavior in (Na,K)(Sb,Nb)O3–SrZrO3–(Bi0.5Na0.5)ZrO3 ceramics, being achieved by engineering the coexistence of multiple local symmetries within the ergodic relaxor zone. The vanished difference between the ground relaxor state and the high‐field supercritical state eliminates polarization hysteresis. The supercritical evolution with electric field enables a highly delayed polarization saturation with continuously increased polarization magnitudes. The results demonstrate that such a design strategy of compositionally induced and field‐manipulated supercritical behavior can be generalizable for developing desirable energy‐storage dielectrics for applications in ceramic/film capacitors.

Tianyu Li

Papers

Fine-grain induced outstanding energy storage performance in novel Bi0.5K0.5TiO3–Ba(Mg1/3Nb2/3)O3 ceramics via a hot-pressing strategy

Energy storage performance of Na0.5Bi0.5TiO3-SrTiO3 lead-free relaxors modified by AgNb0.85Ta0.15O3

Outstanding Energy Storage Performance of Na0.5Bi0.5TiO3-BaTiO3-(Sr0.85Bi0.1)(Mg1/3Nb2/3)O3 Lead-Free Ceramics

TiO2/(K,Na)NbO3 Nanocomposite for Boosting Humidity-Sensing Performances.

Supercritical Relaxor Nanograined Ferroelectrics for Ultrahigh‐Energy‐Storage Capacitors