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Constructing the stepwise phase transition can delay the polarization process of antiferroelectric ceramics, possessing certain significance for improving the energy storage density. However, the common multiphase transitions are obtained in the rare-earth ions doped PbZrO3-based systems. In the present work, the multiphase transition can also be induced in the lanthanum-free Pb(Zr0.5Sn0.5)O3 matrix with mere doping of the alkali-earth metal ion Sr. The introduction of Sr endows the matrix with a higher lattice distortion and the reduced phase-transition temperature. Moreover, related to the induced stepwise electric field-induced phase transition, the energy storage properties are remarkably enhanced to 10.5 J/cm3 and 83.2% when the substitution content of Sr is 3 mol. %. Sr modification can adjust the phase structure by regulating the phase stability of the matrix and suppress the leakage current originating from the structural changes. This work provides a successful attempt that the phase structure and energy storage performance of antiferroelectric ceramics can also be effectively controlled through cheaper and simpler element modification. The optimized energy storage performance provides a new material selection for pulsed power devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel defect engineering is proposed to significantly refine the grain size of energy storage ceramics. • Achieving simultaneously high energy storage density, a rapid discharge time and superior transparency. • In-depth explanations are supported by the DFT calculations and the finite element analysis. • Bright-field TEM revealed the presence of ultrafine grains, PNRs and highly symmetric phase. Ceramic-based transparent dielectric materials are regarded as the best candidates for advanced energy storage and conversion materials because of their outstanding optical and electric properties. Nevertheless, due to the presence of low density, low band gap energy and large grain size, it is difficult to simultaneously obtain high energy storage density and high optical transmittance in lead-free based ceramics, which limiting their further development of practical applications. In this work, the relaxor ferroelectric ceramics of x mol% Er3+-doped 0.91 K 0.5 Na 0.5 NbO 3 -0.09Ba m Sr n TiO 3 (xEr-Sr m Ba n) were constructed via A-site non-stoichiometric defect engineering. It is worth noting that excessive addition of Sr and Ba, especially Sr, can significantly refine the grain size and domain size on account of vacancy-related defect pinning. Finally, high energy storage density (W = 6.39 J/cm3, W rec = 3.42 J/cm3) together with high optical transmittance (∼72% at 900 nm) can be achieved simultaneously in 0.25Er-Sr 1 Ba 0.5 due to the exist of dense structure, ultrafine grain size (<100 nm), small-sized nano-microdomains (i.e., PNRs, < 50 nm) and large bandgap energy (∼3.10 eV). Furthermore, a fast discharge time of 42 ns can also be realized. The above results indicate that the present study helps to promote the development of advanced transparent energy storage and conversion materials. [ABSTRACT FROM AUTHOR]

Dielectric ceramics have attracted wide interest in the field of energy storage. However, high energy density depends on large electric field, seriously threatening the safety of workers and distribution equipment. This work reports excellent energy storage performance of Bi 0.5 Na 0.5 TiO 3 -based transparent ceramics at low electric field. A schematic diagram shows the designed TPC and the corresponding ceramics using the collaborative optimization strategy, including a series of measures (enhancing the energy-storage performance, broadening the stable dielectric platform and reducing both grain and domain sizes). And a practical application scenario for rescue signal transmission when disasters occur is conceived. [Display omitted] • Bi 0.5 Na 0.5 TiO 3 -based transparent energy-storage ceramics were prepared. • High W rec of 3.46 J cm−3 was obtained at a low electric field of 197 kVcm−1. • High stability (Δη/η < 2.2 % and ΔW rec / W rec < 3.1 %) was obtained between 25–200 °C. • Ho/Yb codoping in the ceramics realize real-time fluorescence temperature sensing. • Ceramic-based TPCs can be used in light-pulse signal generator for search and rescue. Transparent dielectric ceramics with ultrafast discharge rates and gigantic power densities are ideal candidates for transparent pulse capacitors (TPCs). However, the requirement of a high external electric field and inferior temperature stability hinder practical applications. (Bi 0.5 Na 0.5)TiO 3 -based ceramics exhibit large polarization and two characteristic dielectric peaks, easy to obtain high energy-storage density under low electric fields (low- E) and maintain stable energy-storage performance (ESP) within a wide temperature range. However, their low optical transmittance (T %) limits their development into TPCs. In this work, to concurrently obtain high T % and excellent ESP and stability under low- E conditions, we propose a collaborative optimization strategy for determining the regulations of grain size, bandgap energy and domain structure. The results show that the pellucidity and energy-storage characteristics improve with decreasing grain and domain sizes. A relatively high T % of 45.6 % (at 710 nm) and recoverable energy-storage density (W rec ∼ 3.46 J cm−3 at 197 kV cm−1) are obtained for the (1- x)[0.85(Bi 0.5-3 y Na 0.5- y Yb 3 y Ho y TiO 3)-0.15SrZrO 3 ]- x BaHfO 3 ceramics. Additionally, the dielectric temperature stability also results in splendid storage temperature stability (Δ W rec / W rec < 3.1 % in the range of 0–200 °C). Importantly, codoping Ho/Yb in the ceramics induces excellent fluorescence temperature sensing feature. The multifunctional TPCs have application potential in the field of search and rescue signal transmission, providing ideas for developing novel optoelectronic devices. [ABSTRACT FROM AUTHOR]

Next‐generation electrical and electronic systems rely on the development of efficient energy‐storage dielectric ceramic capacitors. However, achieving a synergistic enhancement in the polarization and in the breakdown field strength (Eb) presents a considerable challenge. Herein, a heterogeneous combination strategy involving embedding a high Eb plate‐like pyrochlore phase in a high‐polarization perovskite phase is proposed. The embedded plate‐like pyrochlore increases the breakdown field strength and promotes the dynamic polarization response. Meanwhile, the strong spin–orbit coupling effect of the 5d electrons is conducive to the maintenance of the high polarization value of the perovskite. Consequently, the prepared multilayer ceramic capacitor (MLCC) exhibits an ultrahigh Eb and a high polarization. More specifically, an energy storage density (Wrec) of 14.9 J cm−3 with an efficiency of up to 93.4% is achieved for the optimized pyrochlore/perovskite phase. Furthermore, the MLCCs also exhibits an Wrec of ≈ 7.7 J cm−3 ± 4.5% in the temperature range of −50–180 °C. Therefore, this heterogeneous combination strategy therefore provides a simple and effective method for improving the energy‐storage performances of dielectric ceramic capacitors. [ABSTRACT FROM AUTHOR]

[Display omitted] Excellent breakdown electric field and ultrahigh power density can be obtained in this work via multi-scale domain and microstructure engineering. • Multi-scale domain and microstructure engineering of BCZT-based ceramics. • Ultra-fast t0.9 (55 ns) and giant PD (369.9 MW/cm3) were realized. • High Wrec (5.32 J/cm3) and η (∼90%) obtained at 620 kV/cm. • Energy storage properties of BCZT-NBN-HP ceramic exhibit superior stability. Fulfilling the stringent demand of the miniature and eco-friendly pulsed power devices, development of high-energy-storage lead-free dielectric energy storage is critical. To achieve this goal, the mature strategy is to induce the formation of relaxor polar nano regions (PNRs) by means of constructing multiple solid solutions and element doping, which will inevitably lead to a significantly weakened polarization. How to better achieve the domain regulation is a challenge. Here, we reconsidered binary composite-induced domain evolution and designed a novel BT-based binary system with Na 0.7 Bi 0.1 NbO 3 (NBN) modification. By adjusting the NBN content to retain the long-range ferroelectric domains and applying the hot-pressing (HP) method to modulate grain size, the coupling of multi-scale domain morphology and voltage allocation can be achieved, simultaneously contributing to the high polarization, the enhanced breakdown strength and the optimized polarization response. Accordingly, a 130% enhancement to 5.32 J/cm3 in energy storage density, a high energy storage efficiency of ∼ 90%, an ultrafast discharge period of ∼ 55 ns, and a giant power density of ∼ 369.9 MW/cm3 were realized in our HP ceramics, superior to the existing dielectric ceramics. Moreover, the energy storage properties also exhibited superior frequency and thermal stability. The proposed synergistic optimization strategy of the domain morphology regulation and the microstructure adjustment is valuable for further energy storage design, and the enhanced energy storage properties promote the applications for lead-free dielectrics in energy storage devices. [ABSTRACT FROM AUTHOR]

• The local defect structure design is proposed to achieve high energy storage density in NN-based AFE ceramics. • The pinning effect of defect dipoles and the increased local structural disorder stabilize the AFE phase. • High energy storage characteristics (W rec ∼ 9.7 J/cm3, η ∼ 88.75 %) with near-zero P r. • Excellent charge–discharge performance (P D ∼413.2 MW/cm3, W D ∼4.47 J/cm3). Antiferroelectrics (AFEs) are ideal candidates in dielectric, electromechanical, and electrothermal applications. NaNbO 3 (NN), as a lead-free antiferroelectric (AFE) material under extensive investigation, exhibits ferroelectric (FE)-like polarization–electric field (P-E) hysteresis loops, characterized by high remnant polarization and large hysteresis. Herein, the local defect structure design is proposed to achieve high energy storage (ES) density in NN-based AFE ceramics. The pinning effect of defect dipoles and the enhancement of local structural disorder stabilize the AFE phase and reduce hysteresis losses. Consequently, an excellent ES performance of large recoverable energy density (W rec) of 9.70 J/cm3 and high efficiency (η) of 88.75 % is concurrently obtained in NN-based relaxor AFE ceramics, with outstanding charge–discharge performance (P D ∼413.2 MW/cm3, W D ∼4.47 J/cm3), which are significantly improved compared to other reported values in lead-free ES ceramics. This indicates that NN-based ceramics are candidates for advanced ES capacitors and provides a feasible modulation approach for the development of new lead-free high-performance dielectric materials. [ABSTRACT FROM AUTHOR]

• Proposing a novel method to greatly lower sintering temperature and increase the energy storage properties. • The recoverable energy density (11.28 J/cm3) and the energy efficiency (85.54%) are obtained simultaneously. • The power density (332 MW/cm3) and the current density (2144 A/cm2) are acquired. Antiferroelectric (AFE) ceramics with low sintering temperature are of great importance to the application in the Multilayer ceramic capacitors (MLCC). However, conventional method of adding sintering aids will introduce the grain boundary glass phases with low dielectric constant, which is limited in the property enhancement. Thereby new way to simultaneously obtain low sintering temperature and superior performance improvement are urgently needed. Herein, a novel strategy of letting metal cation enter the lattice to avoid the above disadvantages was proposed and one specific attempt was carried out by adding Bi 2 O 3 as raw material instead of sintering aids to introduce Bi3+ into the (Pb 0.98 Sr 0.02)(Zr 0.6 Sn 0.4)O 3 matrix. For all samples containing Bi3+, low sintering temperature of ∼ 1100 °C and outstanding performance improvement are simultaneously achieved. With small amount of Bi3+, the recoverable energy density is prominently enhanced from 7.78 J/cm3 to 11.28 J/cm3 accompanying with high energy efficiency of 85.54%. Meanwhile, outstanding practical discharge performance of ultrahigh current density of 2144 A/cm2 and power density of 332 MW/cm3 can be also achieved. Results testify that the introduction of Bi3+ in lattice truly lowers the sintering temperature and thus densifies the microstructure, maintains high polarization characteristic and promotes the stability of the AFE phase. The proposed novel and effective strategy to further design the dielectric ceramics with low sintering temperature and superior energy storage performance is of great instructive significance for the further development of MLCC and other advanced ceramic capacitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • • Sandwich structured ceramics were prepared successfully by tape casting technique. • • The polarization and electric breakdown strength can be optimized synchronously. • • Ultrahigh energy storage capability (W rec ~ 6 J cm−3, η ~ 95%) can be achieved. • • Energy storage properties exhibited outstanding thermal, frequency and cycle stability. With the rapid development of electronic information technology and the rising environmental concerns as well as the tendency of electronic devices towards miniaturization and integration, enhancing the energy storage properties of lead-free ceramic capacitors is one of the imperative issues. Although a large number of efforts have been contributed to optimize the energy storage properties of lead-free ceramics, the conflict between the polarization and electric breakdown strength seriously impedes the improvement of energy storage density significantly. Herein, inspired by the layered composites of sandwich, the sandwich structured lead-free ceramics based on Bi 0.5 Na 0.5 TiO 3 were designed and fabricated to overcome the above challenge effectively. The theoretical simulations and experiment results demonstrate that the polarization and electric breakdown strength can be optimized synchronously via the sandwich structured design. An ultrahigh recoverable energy storage density of ~ 6 J cm−3 and a nearly ideal energy conversion efficiency of ~ 95% can be obtained for the prepared sandwich structured lead-free ceramics. Meanwhile, the maximum applied electric field can be enhanced to more than 500 kV cm−1. The energy storage capabilities also exhibit outstanding stability over a broad temperature range, frequency range and cycle numbers. These results reveal that the Bi 0.5 Na 0.5 TiO 3 -based lead-free ceramics of this study have a great potential for high energy storage capacitors applications. [ABSTRACT FROM AUTHOR]