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Bi0.5Na0.5TiO3‐based ceramics with high remnant polarization Pr have shown outstanding potential in the application of high‐power ferroelectric transducers. However, low depolarization temperature Td is an obstacle for their application. Here, a composition design strategy was proposed to simultaneously improve the Td and Pr in BNT‐based materials. Ultrahigh Pr of 40.56 µC/cm2 and relative high Td of 184°C were synergistically achieved in (Bi0.5Na0.5)(Ti0.995Mn0.005)O3 (BNMT) ceramics by adding 1.0 mol% BiGaO3 (BG), which is superior to other reported lead‐free systems. The excellent ferroelectric properties were attributed to strengthen ferroelectric order as evidenced by increased rhombohedral distortion. Meanwhile, the enhanced depolarization temperature, increasing from 168°C for x = 0% to 184°C for x = 1.0%, can be ascribed to the suppression of the thermal‐induced ferroelectric‐relaxor phase transition by adding BG. Those results enable the BNMT‐BG systems ceramics to be an attractive candidate for application in high‐power supplies. [ABSTRACT FROM AUTHOR]

(Pb, La)(Zr, Ti)O3 antiferroelectric (AFE) materials are promising materials due to their energy‐storage density higher than 10 J cm−3, but their low energy‐storage efficiency and poor temperature stability limit their application. In this paper, the (1 − x)(Pb0.9175La0.055)(Zr0.975Ti0.025)O3–xPb(Yb1/2Nb1/2)O3 (PLZTYN100x) AFE ceramics were prepared via two‐step sintering method and investigated thoroughly. With the doping of Yb3+ and Nb5+, the phase structure transforms from the orthorhombic phase (AFEO) to the coexistence of the orthorhombic‐and‐tetragonal phases. This structure reduces the free energy difference between the AFE and ferroelectric phases and reduces the fluctuation of energy with temperature, improving the energy storage efficiency and temperature stability. When the x = 0.05 (PLZTYN5), the AFE ceramic exhibits excellent temperature stability and ultrahigh energy storage performance, whose recoverable energy density (Wrec) is 6.8–8.2 J cm−3 at 30 kV mm−1 in the temperature range from −55 to 75°C, and efficiency (ƞ) is 78%–86.7%. In addition, the change of Wrec is less than 15%, exceeding the performance of most AFE ceramics. The results demonstrate that the PLZTYN5 ceramic has great potential in pulse power capacitors. [ABSTRACT FROM AUTHOR]

The energy storage performance of antiferroelectric ceramic capacitors has always gain much attention. Hysteresis, transition field, and polarization intensity are crucial factors influencing energy storage performance. A‐site doped small radius ions have been shown in numerous investigations to enhance the switching field, minimize hysteresis, but decrease maximum polarization intensity. How to maintain the high polarization while optimizing other parameters is a great challenge, and this problem has received scant attention in the research literature to date. In this work, Pb1‐xSrx(Zr0.54Sn0.46)0.975Nb0.02O3 (x = 0, 0.02, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, 0.20) antiferroelectric ceramics show high polarization stability. When the Sr2+ content is within 12 mol%, the saturation polarization intensity always remains at a large value (> 44μC/cm2), and the rate of change is as low as 6%. Pb0.92Sr0.08(Zr0.54Sn0.46)0.975Nb0.02O3 also displays great polarization temperature stability with a minimal change rate of 8.5% in a wide temperature range from ‐55 to 85°C. Additionally, this ceramic also has a superior energy storage performance that the recoverable energy density and energy storage efficiency and 8.95 J/cm3 and 80.4%, respectively. This work paves the way for practical simultaneous polarization and other parameter optimization. [ABSTRACT FROM AUTHOR]

The pressure‐driven force‐electric conversion materials with extremely rapid response time have been widely used in mining, defense, and energy areas. The discharge process by the force‐electric conversion effect in ferroelectrics is dominated by polar‐nonpolar phase transformation. In this work, (Pb0.985La0.01)(ZrxTi1‐x)O3 (PLZT, x = 0.85–0.94) ceramics is designed by tunning Zr4+/Ti4+ ratio and aliovalent La doping to achieve high remnant polarization (Pr) and excellent temperature stability. We focus on the pressure‐driven depolarization in PLZT ceramics, and their corresponding phase structure, ferroelectric properties, dielectric properties, and thermal depolarization. In PLZT (x = 0.93) ceramics, the original polarization P0 increases to 43.42 μC/cm2. The pressure‐driven depolarization releases 37.66 μC/cm2 with the depolarization proportion of 86.73%, which is attributed to irreversible ferroelectric‐antiferroelectric phase transition. It also exhibits excellent temperature stability up to 120°C (> 36 μC/cm2). This work provides a high‐performance alternative to Pb(Zr0.95Ti0.05)O3 and guidance for the development of pulse power energy conversion devices. [ABSTRACT FROM AUTHOR]

Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 ferroelectric ceramics with porous structure of periodic distribution were fabricated successfully via Direct Ink Writing, a type of 3D printing technique. The effect of periodically distributed porous microstructure on the dielectric, ferroelectric, as well as hydrostatic‐pressure‐induced depolarization properties of PZT95/5 ferroelectric ceramics, was investigated. The printed porous ceramics exhibit relatively good viscoelasticity to retain the periodic structure during 3D printing and drying. In contrast with dense PZT95/5 ferroelectric ceramics prepared by conventional solid‐state sintering, low bulk density of the periodically distributed porous PZT95/5 ceramics leads to a decreased remanent polarization of 22.9 µC/cm2 under 2 kV/mm. As the hydrostatic pressure increased, the poled periodically distributed porous PZT95/5 ceramics depolarize sharply under a low and narrow hydrostatic pressure range of 113–116 MPa with a released charge density of 23.9 µC/cm2, while the poled dense PZT95/5 ceramics depolarize under a range of 250–278 MPa. Therefore, the introduction of periodically distributed micropores into PZT95/5 ceramics decreases the ferroelectric‐to‐antiferroelectric phase transition hydrostatic pressure significantly and maintained relatively excellent other properties simultaneously, such as temperature stability and low dielectric loss. The almost sharp depolarization behavior under a significantly decreased hydrostatic pressure demonstrates that periodically distributed porous PZT95/5 ferroelectric ceramics fabricated controllably by 3D printing exhibit excellent performances and prospects in mechanical–electrical energy conversion applications. [ABSTRACT FROM AUTHOR]

(Bi0.5Na0.5)TiO3 (BNT)‐based ferroelectric ceramics have drawn extensive attention because of their excellent electrical properties and interesting depolarization behavior. However, the poor thermal stability of electrical properties limits their practical application. In this work, the effect of sintering temperature (Ts) on the depolarization behavior of BNT‐based ceramics was systematically investigated. It is found that the depolarization temperature Td determined from pyroelectric measurement tends to decrease with increasing Ts, which indicates that lower Ts defers the ferroelectric‐relaxor (FE‐RE) phase transition. However, for the samples sintered at higher Ts (such as 1180°C), although the Td is reduced, the thermal stability is better compared with the sample sintered at lower Ts (1100°C) because the diffuse behavior of the FE‐RE phase transition is suppressed. According to these results, we propose that the thermal stability of electrical properties for BNT‐based ceramics is not only related to high Td, but also to the diffuse degree of phase transition. [ABSTRACT FROM AUTHOR]

Pulse power energy conversion materials with ultrafast discharge processes and ultrahigh power densities have been widely used in the defense, energy, medical, and mining fields. The pressure‐driven depolarization in ferroelectric materials is significant and accounts for the discharge processes. In this study, we focus on pressure‐induced depolarization in (Pb1‐1.5xLax)(Zr0.80Ti0.20)O3 (PLZT) (x = 0‐0.07) ceramics, and their corresponding phase structure, dielectric properties, ferroelectric properties, and thermal depolarization performances. Although a satisfactory pulse power energy conversion performance has been achieved in Pb(Zr0.95Ti0.05)O3 materials, poor temperature stability negatively influences their application. The static charge densities of PLZT (x = 0.04, 0.06) decreased from 29.11 μC/cm2 and 31.53 μC/cm2 to 19.76 μC/cm2 and 6.56 μC/cm2 under 400 MPa hydrostatic pressure, respectively, which is attributed to a pressure‐driven ferroelectric‐antiferroelectric phase structural transition. In particular, the temperature stability of PLZT (x = 0.06) materials is up to 87°C. This study may guide the further development pulse power energy conversion devices. [ABSTRACT FROM AUTHOR]

Ceramic‐based dielectric capacitor are highly suitable for pulsed power applications due to their high power density and excellent reliability. However, the ultrahigh applied electric field limit their applications in integrated electronic devices. In this work, (1−x){0.96(Bi0.5Na0.5)(Ti0.995Mn0.005)O3‐0.04BiAlO3}‐xNaNbO3 (BNT‐BA‐xNN, x = 0, 0.04, 0.08, 0.12, and 0.16) ternary ceramics were designed to achieve excellent energy storage properties. It was found that the introduction of NaNbO3 (NN) effectively increase the difference (ΔP) between Pmax and Pr, resulting in an obvious enhancement of the energy storage properties. High recoverable energy storage density, responsivity, and power density, that is, Wrec = 2.01 J/cm3, ξ = Wrec/E = 130.69 J/(kV⋅m2), and PD = 25.59 MW/cm3, accompanied with superior temperature stability were realized at x = 0.14 composition. In addition, the thermal stable dielectric properties of the sample can be prominently improved with increasing NN content. The temperature coefficient of capacitance (TCC) of x = 0.16 composition is lower than 15% over the temperature range from 49°C to 340°C, with a high dielectric permittivity of 1647 and a low dielectric loss (0.0107) at 150°C. All these features show that the BNT‐BA‐xNN ceramics are promising materials for energy storage application. [ABSTRACT FROM AUTHOR]

Ferroelectric materials under shock compression can generate current and power by a drastic change of the remnant polarizations and surface bound charge. This behavior has been employed in applications involving nuclear fusion trigger, energy storage devices, and high pulse power sources. Despite the large power output in lead‐containing ferroelectrics, lead‐free materials are highly desirable owing to the environmental concerns. Herein, the phase transition behaviors and current outputs of 0.92Bi0.5Na0.5TiO3‐0.08BiAlO3 (BNT‐8BA) materials are studied under high pressure. The BNT‐8BA ferroelectric ceramics can be completely depolarized from polar to the nonpolar state under shock compression, resulting in a current output in the external circuit. The phase‐transition‐induced depolarization pressures of BNT‐8BA are lower than those of the pure Bi0.5Na0.5TiO3 under both dynamic and static high‐pressure loads. These results can allow the understanding of the high‐pressure behavior of BNT‐8BA for application as ferroelectric pulsed power supply. [ABSTRACT FROM AUTHOR]

Solid solutions of (1−x)PbZrO3‐xBa(Mg1/3Nb2/3)O3 (PZ‐xBMN, x = 0.02, 0.03, 0.04, and 0.05) were prepared, and their microstructures, electrical properties, and phase transition behaviors under hydrostatic pressure were investigated. It was found that the incorporation of BMN into PZ can provide improved ferroelectric properties, leading to the formation of antiferroelectric/ferroelectric phase boundaries in PZ‐xBMN ceramics when the value of x is between 0.02 and 0.03. It was also demonstrated that the ferroelectric phases exhibit excellent temperature stability in the remanent polarization. Importantly, complete depolarization was observed in the PZ‐xBMN solid solution due to the hydrostatic pressure‐induced ferroelectric‐antiferroelectric phase transition. The resultant properties and phase transition behaviors of PZ‐xBMN ceramics under pressure will benefit their application in pulsed power supplies. [ABSTRACT FROM AUTHOR]

Abstract: (1−x)Bi1/2Na1/2TiO3‐xPbMg1/3Nb2/3O3[(1−x)BNT‐xPMN] ceramics have been fabricated via a conventional solid‐state method for compositions x ≤ 0.3. The microstructure, phase structure, ferroelectric, and dielectric properties of ceramics were systematically studied as high‐temperature capacitor materials. XRD pattern certified perovskite phase with no secondary phase in all compositions. As PMN concentration increased, the phase of (1−x)BNT‐xPMN ceramics transformed from ferroelectric to relaxor gradually at room temperature, with prominent enhancement of dielectric temperature stability. For the composition x = 0.2, the temperature coefficient of capacitance (TCC) was <15% in a wide temperature range from 56 to 350°C with high relative permittivity (>3300) and low dielectric loss (<0.02) at 150°C, which indicated promising future for (1−x)BNT‐xPMN system as high‐temperature stable capacitor materials. [ABSTRACT FROM AUTHOR]

Abstract: The effect of lanthanum (La) content on the phase transformation of Pb1−3x/2Lax(Zr0.42Sn0.40Ti0.18)O3 (PLZST 100x/42/40/18, 0 ≤ x ≤ 0.06) ceramics was investigated by the dielectric and ferroelectric properties. The base composition PLZST 0/42/40/18 located in the ferroelectric (FE) rhombohedral phase region. As x increased, the compositions showed successively FE and antiferroelectric (AFE) state at room temperature, and their peak temperatures (Tmax) decreased gradually in line as Tmax = 162.21‐1507x. Evidence was presented that there were two dielectric anomalies in PLZST 2/42/40/18, which were corresponding to the FE‐AFE and AFE‐paraelectric (PE) phase transformations, respectively. With increasing the dc bias fields, the two phases merged into one. PLZST 3/42/40/18 showed AFE characteristics with the first loop outside of the second loop and there was only one dielectric inflection. The critical lanthanum content occurred at x = 0.03 from the dielectric temperature spectra and hysteresis loops. Furthermore increase in La above 0.03, these compositions showed typical antiferroelectric behaviors with double hysteresis loops. The stored energy properties of the three compositions (PLZST 4/42/40/18, 5/42/40/18 and 6/42/40/18) displayed different temperature dependencies from room temperature to 140°C (over their respective Tmax). Comparing the above results with previous investigations on PLZSTs, some questions were discussed. [ABSTRACT FROM AUTHOR]

Dynamic hysteresis of Nb-doped Pb( Zr1− x Ti x) O3 ( PZT, 0.20 ≤ x ≤ 0.60) ceramics were studied systemically at different field ( E) and frequency ( f). The hysteresis loops were strongly dependent on E and f. The measured coercive fields ( Ec0) were far lower than the calculated values based on the Landau-Ginzburg theory, and increased dramatically from the rhombohedral phase to the tetragonal phase while had less variation with composition in the same phase. With increasing E or f for each composition, three types of loops were observed: linear, minor, and saturated loops. The cross fields ( E0), cross polarizations ( P0), and hysteresis areas ( ) showed different variation regularities with f. Similar varying curves were observed for all PZT ceramic samples by normalizing E0, P0, and with E/Ec0, which indicated the same polarization switching for different domain structures. Further analyses revealed that the switching processes can be divided into three stages: space charge polarization, domain switching, and steady state. The first and second stage occurred at ~0.5 and ~1.5 E/ Ec0, respectively. These results would be very helpful to further understand the polarization switching of ferroelectric ceramics. [ABSTRACT FROM AUTHOR]

In this paper, the influence of phase evolution on polarization change and electrocaloric response in lead-free (Ba0.9Ca0.1)(Ti1− x Zr x)O3 ceramics ( BCTZ) was systematically investigated. With increasing Zr/Ti ratio, the phase structure and phase transition behavior were greatly changed, resulting in various temperature and electric field dependence of electrocaloric responses. For x=0.05, a peak electrocaloric temperature change 1.64 K (at 130°C) and corresponding entropy change 1.78 J·kg−1·K−1 were obtained for 0-7 kV·mm−1 electric field. Negative electrocaloric temperature change in −0.1 K was obtained below Curie temperature ( Tc), which may be induced by the orthorhombic-tetragonal ferroelectric phase transition. With the increase in x, the peak value of the electrocaloric response decreased but much better temperature stability was observed. Simultaneously the negative electrocaloric response gradually disappeared with the disappearance of the low temperature ferroelectric-ferroelectric phase transition. For x=0.2, electrocaloric response showed good temperature stability ranging from room temperature to 130°C, attributing to the relaxor ferroelectric feature. [ABSTRACT FROM AUTHOR]

PZT95/5 ferroelectric ceramics are widely utilized in pulsed power devices and the remanent polarization Pr of poled PZT95/5 can characterize the shock-driven energy density. However, this remanent polarization is difficult to be measured nondestructively. In this article, a series of pyroelectric tests of poled PZT95/5 ceramics were conducted near room temperature, from 25°C to 20°C. A linear relation between Pr and pyroelectric coefficient p was found, that is, Pr=1190.5( K)× p, which provides an effective way to nondestructively estimate the value of Pr of the poled PZT95/5 ceramics by measuring the pyroelectric coefficient p at room temperature. According to Devonshire's phenomenological theory, this result could be explained by a modified equation: [ABSTRACT FROM AUTHOR]

(Bi0.5Na0.5)TiO3-BiAlO3 lead-free materials exhibit excellent ferroelectric properties, but its depolarization temperature is relatively low which is the major obstacle limiting the material's practical application. In this study, the effects of Manganese (Mn) modification on the microstructure, ferroelectric properties and depolarization behavior of 0.96(Bi0.5Na0.5)(Ti1− xMn x)O3-0.04BiAlO3 ceramics were investigated. It was found that the average grain size was enlarged and ferroelectric properties were enhanced with small Mn addition, meanwhile the tangent loss decreased. The remnant polarization ( Pr) of the samples reached an optimal value (~41 μC/cm2) as Mn content increased up to 0.7 mol%, whereas further addition resulted in the decrease in Pr. Moreover, appropriate Mn addition ( x=0.7%) can improve the depolarization temperature from 140°C to 161°C determined from thermally stimulated depolarization currents measurement. [ABSTRACT FROM AUTHOR]

The low-temperature sintering and electric properties of Pb0.99( Zr0.95 Ti0.05)0.98 Nb0.02 O3 ( PZTN 95/5) ferroelectric ceramics with CuO addition was investigated. The CuO addition significantly promoted the densification and reduced the sintering temperature of PZTN 95/5 ceramics by more than 200°C. The 0.2 wt% CuO-added sample sintered at 1150°C exhibited the optimum relative density of 96.7% and excellent electric properties with values of Pr = 37.80 μC/cm2, TC = 223°C, εr = 329, and tan δ = 0.016, which were superior to that of PZTN 95/5 ceramics sintered at 1350°C. [ABSTRACT FROM AUTHOR]