Innovative Design of BNKT-xSLZT Ceramics: Maximizing the Polarization Difference for Enhanced Energy Storage

Abstract

Lead-free relaxor ferroelectric ceramics with outstanding energy-storage (ES) density (W rec ) and high ES efficiency (η) are crucial for advanced pulse-power capacitors. This study introduces a strategic approach to maximizing the polarization difference (ΔP) by inducing a transition from the ferroelectric phase to the ergodic relaxor (ER) phase. By employing this strategy, a series of ceramics, (1 − x)(Bi 0.5 Na 0.4 K 0.1 )TiO 3x(Sr 0.85 La 0.1 )(Zr 0.5 Ti 0.5 )O 3 (BNKT-xSLZT), with varying SLZT content (x = 0.05, 0.10, 0.15, and 0.20), were designed. The addition of SLZT enhances cationic disorder, induces vacancies at A sites, and disrupts long-range ferroelectric order, facilitating the formation of polar nanoregions and enhancing relaxor ferroelectric behavior. Furthermore, a viscous polymer process (VPP) technology is employed to optimize the ceramics' structure, aiming to increase the breakdown strength (E b ) and enhance ΔP. Ultimately, enhanced ES performance is demonstrated in BNKT-0.15SLZT VPP , achieving a remarkable W rec of 6.85 J/cm 3 and η of 84% under 470 kV/cm. This composition demonstrates excellent stability with minimal variations in W rec (3.0%) and η (4.4%) over the temperature range of 20−110 °C. Additionally, BNKT-0.15SLZT VPP exhibits exceptional pulse charge−discharge properties, featuring a high discharge density of 3.72 J/cm 3 , a large power density of 164.2 MW/cm 3 , and a short discharge time (t 0.9 ) of 193 ns under 300 kV/cm. The study validates the practicality of BNKT-0.15SLZT VPP for pulse capacitors and underscores the potential to enhance ES performance through A-site donor doping and VPP technology. This work provides a comprehensive understanding of the interplay among composition, structure, and ES properties in lead-free relaxor dielectric ceramics, laying the groundwork for innovative advancements in the field.

Synergistic Optimization Unveils Remarkable Energy Storage Enhancement in Silver Niobate-Based Ceramics

“…Leveraging the VPP technique, as depicted in Figure b, to reduce grain size and enhance material density proves instrumental in further enhancing BDS. , Furthermore, the deliberate substitution of Bi 3+ for Ag + at the A-site plays a pivotal role. The strong hybridization of Bi 3+ 6 s orbitals with O 2– 2 p orbitals enhances macroscopic polarization, , while the smaller radius of Bi 3+ compared to Ag + decreases the tolerance factor and increases oxygen octahedral tilting, thereby stabilizing the AFE phase, as illustrated in Figure c. Remarkably, through this synergistic optimization strategy, as illustrated in Figure d, we achieved outstanding results, including a high P max of 41.6 μC/cm 2 , an elevated BDS of 470 kV/cm, and an exceptional W rec of 7.06 J/cm 3 in (Ag 0.955 Bi 0.015 )(Nb 0.75 Ta 0.25 )O 3 ceramics.…”

Utilizing Domain Engineering to Achieve High-Polarization Relaxor Ferroelectrics for Low-Consumption Ceramic Capacitors

“…According to eqs and , in the underdamped condition, the variations between current ( I max ), current density ( C D ), power density ( P D ), and applied electric field were calculated and plotted in Figure e1. C normalD = I max S P normalD = E I max 2 S In the overdamped condition, the time dependence of the discharge energy density ( W D ) of 0.90BCZT-0.10NN ceramic under different electric fields, plotted in Figure e2, can be calculated using eq . W normalD = R ∫ i 2 t nobreak0em0.25em⁡ normald t / V R , V , I , and t represent the load resistance, ceramic volume, and discharge current, and t . The W D at 300 kV/cm was calculated to be ∼2.46 J/cm 3 , ∼ 30% smaller than that from the P–E measurement, and was caused by the incomplete domain switching behavior. − The t 0.9 is ∼140 ns, indicating the potential for pulsed power capacitor applications.…”

“…The fast charge–discharge capability of dielectric capacitors offers significant advantages over other power systems, with research primarily focusing on enhancing energy storage density ( W rec ) by improving voltage endurance, − as detailed in the Supporting Information. However, with the ongoing trend toward the miniaturization of electronics, high W rec is not always essential. − Furthermore, indiscriminately increasing the electric breakdown strength ( E b ) of dielectrics leads to a reduction in W rec per unit electric field (WTUEF), a novel concept introduced by the authors to describe the energy efficiency of dielectric capacitors in terms of energy storage per unit breakdown strength ( W rec / E b ).…”

High‐entropy strategies boosting dielectric temperature stability in (Na0.4K0.1Bi0.5)TiO3 ceramics

“…The capacitance behavior of dielectric capacitors undergoes substantial variations in response to voltage and temperature changes. [1][2][3] Particularly in demanding sectors like deep-well drilling and aerospace industries, electronic equipment is frequently subjected to high-temperature environments (>150 • C). Consequently, it becomes imperative for ceramic dielectric capacitors to exhibit exceptional temperature stability and voltage resilience to cater to the stringent requirements of these applications.…”