Simultaneous Enhancement of Energy Storage and Hardness Performances in (Na_0.5Bi_0.5)_0.7Sr_0.3TiO₃-Based Relaxor Ferroelectrics Via Multiscale Regulation

Abstract

For (Na0.5Bi0.5)0.7Sr0.3TiO3-based (BNST) energy storage materials, a critical bottleneck is the early polarization saturation and low breakdown electric field (E b), which severely limits further development in the field of advancing pulsed power capacitors. Herein, a strategy, via multiscale regulation, including synergistically manipulation of the domain configuration and microstructure evolution in BNST-based ceramics, is propounded through introducing LiTaO3(LT). The composition-driven fine domain size, as demonstrated by macroscale (size effect and dielectric response) and mesoscale (domains relaxor behavior) analysis, provides robust evidence of delayed polarization saturation and large polarization difference. Theoretical simulations and experimental results confirm that the fine grain size, uniform grain size distribution, and insignificant secondary phase contribute to the enhancements of E b. Further analyses of the intrinsic electronic structure reveal the intrinsic mechanism for enhancing E b via first-principles calculations on the basis of density functional theory. Consequently, owing to improved E b, delayed polarization saturation, and refined grain size, excellent comprehensive performances [high W rec of 5.52 J/cm3, large η of 85.68%, high hardness H of 7.06 GPa, and broad operating temperature range (20–140 °C)] are realized. We believe that these findings can provide a thorough understanding of the origins of excellent comprehensive performances in BNST-based ceramics as well as some guidance in the exploration of materials with high-performance lead-free capacitors for application in future pulsed power systems.

Delayed Polarization Saturation Induced Superior Energy Storage Capability of BiFeO3‐Based Ceramics Via Introduction of Non‐Isovalent Ions

“…For typical FEs (with large size domains, such as BFO), the polarization increases rapidly at low applied electric field and reaches saturation due to the energy simplification of the many possible polarization directions. [27] After removing the applied electric field, the G curves are bounced resulting from the presence of the random field. However, the polar phase in FEs with high intrinsic potential barrier is difficult to, be crossed after uninstalling the electric field; thus, leading to high P r .…”

Utilization of Nonstoichiometric Nb5+ to Optimize Comprehensive Electrical Properties of KNN-Based Ceramics

“…Diffuse phase transition (DPT) behavior of perovskite ferroelectrics can be evaluated via a modified Curie–Weiss law ,− ε = C / .25em ( T − T 0 ) normalΔ T normalm = T normalc normalw − T normalm 1 ε normalr − 1 ε normalm = false( T .25em − .25em T normalm false) γ C …”

“…Diffuse phase transition (DPT) behavior of perovskite ferroelectrics can be evaluated via a modified Curie–Weiss law ,− …”

Superior Energy Density Achieved in Unfilled Tungsten Bronze Ferroelectrics via Multiscale Regulation Strategy

“…As a result, W rec increases to 5.895 J cm −3 with an enhancement of 50.69%, and 𝜂 is also improved to 85.37%. The achievement of optimized composition of Sr 0.425 La 0.1 □ 0.05 Ba 0.425 Nb 1.4 Ta 0.6 O 6 can also be supported by a systematical investigation on the [17,18,[22][23][24][27][28][29][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] structure and properties of Sr 0.425 La 0.1 □ 0.05 Ba 0.425 Nb 2−x Ta x O 6 ceramics with different Ta 5+ concentrations, which is summarized in Figures S1-S4 (Supporting Information). A comparison of the ESP of our SLBNT ceramics and previously reported lead-free bulk ceramics are illustrated in Figure 2e.…”

“…It is evident that the excellent overall performance of SLBNT ceramics leads the field in tetragonal tungsten bronze structure ferroelectric ceramics and can even be comparable with some state-of-the-art perovskite structure ceramics. [17,18,[22][23][24][27][28][29][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] Figure 3a shows the X-ray diffractometer (XRD) patterns of SBN, SLBN, and SLBNT ceramics. All the patterns reveal pure tungsten bronze structure, indicating that the La 3+ and Ta 5+ successfully entered the SBN host lattice.…”