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By chemical substitutions with Ba2+ and La3+ at A-site in PbHfO 3 -based ceramics, an ultrahigh energy storage efficiency of 91% and high energy density of 7.3 J cm−3 are achieved simultaneously at 290 kV cm−1 in Pb 0.925 Ba 0.045 La 0.03 (Hf 0.6 Sn 0.4) 0.9925 O 3 ceramics. [Display omitted] Near-zero remanent polarization, high breakdown electric field, high saturation polarization and low electrical hysteresis are necessary conditions for antiferroelectric ceramics to obtain excellent energy storage performance. Here, Pb 0.925 Ba x La 0.075−x (Hf 0.6 Sn 0.4) 0.98125+x/4 O 3 lead-based antiferroelectric ceramics were prepared by a rolling process. The composition modulations of Ba and La are beneficial to adjust the phase switching field, improve the saturation polarization and reduce the electrical hysteresis, leading to an enhanced energy storage performance. Simultaneously, the Pb 0.925 Ba 0.045 La 0.03 (Hf 0.6 Sn 0.4) 0.9925 O 3 ceramic exhibited a high energy storage density of 7.3 J cm−3 and an energy storage efficiency of 91%, revealing that this composition is an outstanding candidate in pulsed energy storage application and lays a foundation for further study on the energy storage performances of PbHfO 3 -based antiferroelectric ceramics. [ABSTRACT FROM AUTHOR]

Ceramics of Y 2 GaSbO 7 (YGSO) were prepared by the solid-state reaction method. The ceramics were confirmed by XRD and TEM to exhibit the Fd-3 m (227) space group and a cubic pyrochlore structure within the temperature range of 1420–1500 °C. XPS verified that the valence states of Y, Ga, and Sb in the ceramics were + 3, + 3, and + 5, respectively. Additionally, the relationship between the FWHM of the notable peak at 775 cm−1 and the Q × f value was elucidated through Raman spectroscopic analysis. The analysis of the P-V-L theory revealed that the Sb-O bond is crucial in determining ε r , while the values of τ f and Q × f are affected by the Y-O bond. At 1460 °C, YGSO ceramics obtained the maximum relative density (97.5%) and the best microwave dielectric properties (ε r = 14.78, Q × f = 50,153 GHz, and τ f = –22.3 ppm/°C). • For the first time, a Y 2 GaSbO 7 microwave dielectric ceramic with a pyrochlore structure was discovered. • The Raman spectra of the ceramics were analyzed, and the valence state was studied using XPS. • TEM analysis confirmed the cubic structure of Y 2 GaSbO 7 ceramics. • SEM images revealed the microstructure of the ceramic grains, with the maximum relative density reaching 97.5%. • The relationship between α , f i , E b , U b , and the dielectric properties of Y 2 GaSbO 7 ceramics was examined using P-V-L theory. [ABSTRACT FROM AUTHOR]

Electrocaloric (EC) refrigeration materials have seen significant progress recently, with efficient Barium titanate-based (BT-based) lead-free materials particularly promising for microelectronics applications. However, their performance still lags behind their lead-based counterparts, highlighting the need for further improvements. This study employs a novel density adjustment strategy (DAS) to enhance the EC performance of (0.5- x)BCT-BTZ- x BST ceramics by carefully balancing the relationships among density, dielectric breakdown strength (BDS), and Δ T. Although Δ T intuitively decreases with increasing density, enhanced BDS can partially compensate for this decrease. An excellent EC performance with Δ T of 2.21 K and Δ T /Δ E of 0.471 K mm kV−1 is obtained in x = 0.5, together with a broader temperature span of 50.3 °C near room temperature, which surpasses or is comparable to other lead-free or lead-based ones. The results suggest that the DAS provides a promising approach for developing efficient EC, making speediness of application in EC devices. [Display omitted] • Developed innovative density adjustment strategy (DAS) for (0.5- x)BCT-BTZ- x BST ceramics to reconcile ρ and Δ T relationship. • Excellent EC properties (Δ T = 2.21 K, Δ T /Δ E = 0.471 K mm kV−1, T span =50.3 ℃) achieved by balancing ρ, BDS, and Δ T. • Identified physical mechanisms responsible for enhanced EC properties. [ABSTRACT FROM AUTHOR]

Silver niobate (AgNbO 3 , AN) dielectric ceramics and their antiferroelectric behavior have attracted increasing attention for their potential applications in energy-storage capacitors. However, AN's inferior dielectric breakdown strength, recoverable energy storage density, and efficiency have limited its application. In this work, a combination of chemical composition design and liquid-phase sintering was considered for the fabrication of highly insulated and desensitized AN-based ceramics for enhancing E b , W rec , and η of AN. We design and prepare (1 − x)AgNbO 3 - x (Sr 0.7 Bi 0.2)HfO 3 (AN-100 x SBH, x = 0.00–0.06) ceramics with the addition of 1 mol% BaCu(B 2 O 5) (BCB) as a sintering aid to realize this. It is found that highly desensitized ceramics can be formed at 1000–1030 °C over the course of 2 h. The electrical property characterization results indicate that the AFE state and E b are significantly enhanced with increasing SBH concentration. High W rec and η values of 6.1 J/cm3 and 73%, respectively, under an applied field of 330 kV/cm are achieved in the AN-5.5SBH ceramic. Meanwhile, the AN-5.5SBH ceramic shows excellent thermal stability over a wide temperature range (25–120 °C) under an externally applied field of 290 kV/cm, in which the fluctuations of W rec and η are 3.8% and 1.5%, respectively. These results provide an effective method for obtaining AN-based ceramics with excellent electrical properties under a lower sintering temperature than that required for pure AN ceramics. This method could be further generalized to develop new lead-free energy-storage dielectric materials. • AgNbO3-based dielectric ceramics with stabilized antiferroelectricity synthesized. • Ceramics with dense microstructure successfully sintered at 1000–1030 °C for 2 h. • High recoverable energy storage density (6.1 J/cm3) and efficiency value (73%) achieved. • Energy storage properties stable over the temperature range of 25–120 °C. [ABSTRACT FROM AUTHOR]

The Ba x Sr 1-x TiO 3 -spinel composite ceramics of (1-x)Ba 0.4 Sr 0.6 TiO 3 (BST40) -xCuGa 2 O 4 (CG) (x = 10, 30, 50 and 70 wt%) were prepared at median temperature through a solid-state sintering process. The relationships between ion interdiffusion, microstructure and dielectric properties were studied. With the increase of CG content, the Curie temperature (T C) shifted to higher temperature and the dielectric relaxation characteristics of the composites were gradually increased. The dielectric properties of the composites were well optimized by the addition of the CG additives since the shifting of T C and its superior composite effect. The composite with 50 wt% CG had the best performance that the permittivity was 198 (at room temperature), the tunability was 15.5% (at 30 kV/cm) and the Q value was 446 (at 2.493 GHz). • T C shifts towards high temperature, which is different from other systems reported, is conducive to gain large tunability. • The BST40-CuGa 2 O 4 performed enhanced dielectric properties (high tunability, high Q values versus low permittivity) compared to pure BST40. • T C shift to high temperature achieved dual goals of medium temperature sintering and reasonable modification in BST-Cu 2 Ga 2 O 4. [ABSTRACT FROM AUTHOR]