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Lead‐free ceramic capacitors with high energy storage density are desired. Herein, the novel (1–x)(0.9Bi0.5Na0.5TiO3‐0.1SrTi0.85Zr0.15O3)‐xNa0.95Ca0.04Li0.01Nb0.96Zr0.04O3 [(1–x)(BNT‐STZ)‐xCZNNL, x = 0.1, 0.2, 0.3, 0.4 and 0.5] ceramics are prepared via citrate combustion technology and two‐step sintering method. The dense microstructures are observed and slim hysteresis loops are realized as addition of CZNNL. The enhanced recoverable energy storage density (Wre of 2.52 J cm−3) with high efficiency (η of 80%) is obtained in 0.6(BNT‐STZ)‐0.4CZNNL ceramic under a moderate electric field of 200 kV cm−1. Moreover, excellent thermal stability (Wre varies <1% and η varies <3.5%) at 20 to 100 °C) and excellent fatigue resistance are achieved for 0.6(BNT‐STZ)‐0.4CZNNL ceramic. [ABSTRACT FROM AUTHOR]

The pursuit of lead-free ceramic capacitors with superior energy storage properties has garnered increasing attention. The energy storage properties of Bi0.5Na0.5TiO3 (BNT) can be feasibly adjusted by forming solid solutions with other components. Herein, 0.8Bi0.5Na0.5TiO3–0.2SrTiO3–xBi(Mg2/3Nb1/3)O3 (BNT–ST–xBMN) ceramics were synthesized via citrate combustion technology. The results show that BMN-doped BNT–ST ceramics induce dielectric relaxation behavior and slim hysteresis loops are realized. An optimized recoverable energy storage density (Wre of 2.85 J/cm3) and efficiency (η of 83%) are obtained in 1.5 mol% BMN-doped BNT–ST ceramic under relatively low electric field of 200 kV/cm. The ceramics show excellent frequency stability (Wre varies < 1.4% and η varies < 1% at 10 to 100 Hz). Moreover, both Wre and η maintain an increasing trend with increasing temperature. [ABSTRACT FROM AUTHOR]

Ba0.7Sr0.3TiO3 added with 1 mol% B3+ and x mol% Mn2+ (BSTBM) ceramics were synthesized using citrate combustion technique. An enhanced electrocaloric effect has been reported in BSTBM ceramic. The addition of B3+ and Mn2+ ions lowers the sintering temperature of BSTBM ceramics to 1200 °C. The ceramic sample with x = 0.5 exhibits homogeneous grain size, low dielectric loss and large polarization. More importantly, the ceramic sample with x = 0.5 shows the excellent electrocaloric properties (adiabatic temperature change, ΔT = 0.86 K, and electrocaloric responsivity, ΔT/ΔE = 0.43 K m MV−1) under electric field of 20 kV/cm and room temperature. Moreover, a high ΔT of 3.08 K and ΔT/ΔE of 0.31 K m MV−1 are obtained under electric field of 100 kV/cm near room temperature for this composition. Highlights: The addition of B3+ and Mn2+ lowers the sintering temperature of BSTBM ceramic. Improved microstructure and enhanced electrocaloric properties are realized. Large adiabatic temperature change ΔT = 3.08 K is obtained at 100 kV/cm. ΔT = 0.86 K and ΔT/ΔE = 0.43 K m MV−1 are realized at 37.5 °C and 20 kV/cm. [ABSTRACT FROM AUTHOR]

Lead‐free (1–x)Ba0.9Sr0.1TiO3–xBi(Mg0.5Zr0.5)O3 ((1–x)BST–xBMZ, x = 0–0.15) ceramics are synthesized via citrate combustion process. The grain size is reduced and slimmer hysteresis loops are realized as addition of BMZ. (1–x)BST–xBMZ ceramics exhibit typical relaxor characteristics as x increases. The recoverable energy storage density (Wre = 2.1 J cm−3) and efficiency (η = 88%) are obtained for 0.9BST‐0.1BMZ sample. The energy storage properties of 0.9BST‐0.1BMZ ceramic show excellent frequency stability (Wre varies 4.5% and η varies 1.8% at 5–100 Hz). Moreover, as the temperature increases from 25 °C to 100 °C, the variation of Wre is 7.1% and η keeps unchanged (88%) at 100 kV cm−1. [ABSTRACT FROM AUTHOR]

Lead-free ceramic capacitors have attracted growing demand for energy-storage. Here, (1 − x)[(Bi0.5Na0.5)0.94Ba0.06]0.98La0.02TiO3–xBi(Mg0.5Zr0.5)O3 ((1 − x)BNBLT–xBMZ, x = 0–0.3) ceramics were synthesized via citrate combustion technology. The nanoscale domains are observed and slim hysteresis loops are realized as addition of BMZ. The recoverable energy-storage density (Wre of 2.6 J/cm3) and efficiency (η of 81%) are obtained in 0.8BNBLT-0.2BMZ sample under 160 kV/cm. The energy-storage performances of 0.8BNBLT-0.2BMZ sample show excellent frequency stability (Wre varies 4% and η varies 2.5% at 5 Hz to 100 Hz). More importantly, Wre increases from 1.02 to 1.36 J/cm3 with increasing temperature from 20 to 120 ºC, and η increases from 80 to 97% at 100 kV/cm, which demonstrates that it is the promising candidate for high temperature energy-storage devices. [ABSTRACT FROM AUTHOR]

A traditional solid-phase sintering technique was used to prepare the (0.98-x)K0.4Na0.6Nb0.94Sb0.04O3-xBi0.5Li0.5ZrO3-0.02SrZrO3 ternary ceramics, whose crystal structures were identified by X-ray diffraction method combined with dielectric-temperature measurements. It was found that there existed a rhombohedral-orthorhombic-tetragonal phase boundary when x = 0.03 to 0.04. The maximum values of piezoelectric constant d33 and planar electromechanical coupling coefficients kp both appeared at x = 0.03, being 263 pC/N and 0.39, respectively. Furthermore, adding too much Bi0.5Li0.5ZrO3 was noted to hinder the grain growth of the ceramics via the observation of microstructures with a scanning electron microscope. [ABSTRACT FROM AUTHOR]

Lead‐free (1−x)Bi0.5(K0.15Na0.85)0.5TiO3‐xSr(Ti0.85Zr0.15)O3 ((1−x)BKNT‐xSTZ, x = 0.1–0.4) ceramics are synthesized by citrate combustion method. The grain size is reduced, and the high‐temperature shoulder dielectric peak (Tm) shifts toward low temperature, while the low‐temperature shoulder dielectric peak (Ts) shifts toward high temperature as x increases. The remnant polarization decreases and slimmer hysteresis loops are realized with x increasing. The optimal energy density (Wre ≈2.85 J cm−3) with high efficiency (η ≈ 81%) is obtained for 0.7BKNT‐0.3STZ at 160 kV cm−1. More importantly, excellent frequency stability and enhanced temperature‐dependent energy properties (Wre ≈ 1.12 J cm−3 and η ≈ 94%) of 0.7BKNT‐0.3STZ ceramic are obtained at 100 kV cm−1 and 120 °C. [ABSTRACT FROM AUTHOR]