Ultrahigh Energy-Storage Performances in Lead-free Na_0.5Bi_0.5TiO₃-Based Relaxor Antiferroelectric Ceramics through a Synergistic Design Strategy

Abstract

Dielectric ceramics with outstanding energy-storage performances are nowadays in great demand for pulsed power electronic systems. Here, we propose a synergistic design strategy to significantly enhance the energy-storage properties of (1 – x)­(0.94Na0.5Bi0.5TiO3-0.06BaTiO3)-xCaTi0.75Ta0.2O3 solid solution ceramics through introducing polar nanoregions, shifting rhombohedral to tetragonal phase transition below room temperature (stable antiferroelectric characteristic), as well as increasing the band gap in the system. Ultrahigh energy-storage properties with a record value of recoverable energy-storage density W rec ∼ 9.55 J/cm3 and a high efficiency η ∼ 88% are achieved in Na0.5Bi0.5TiO3-based bulk ceramics with x = 0.24. Moreover, high W rec (>3.4 J/cm3) and η (>90%) with a variation of less than 6% can be observed in a wide frequency and temperature frequency range of 5–200 Hz and 25–140 °C. Our research result not only indicates the great possibility of Na0.5Bi0.5TiO3-based lead-free compositions to replace lead-based energy-storage ceramics but also gives an effective strategy to design ultrahigh energy-storage performances for eco-friendly ceramics.

Phase and Band Structure Engineering via Linear Additive in NBT-ST for Excellent Energy Storage Performance with Superior Thermal Stability

“…The component-dependent peak positions and intensities for the modes are shown in the contour plot in Figure d. The positions of the 200–700 cm –1 modes (B 1 , B 2 , C 1 , C 2 , and C 3 bands) shift toward lower wavenumbers as the CTN content increases, a phenomenon related to the structural disorder factor and the increase in the size of the unit cell of the nonpolar phase with increasing doping content . Therefore, the addition of CTN increases the ionic disorder, which is the key factor to breaking the long-range ferroelectric order and generating PNRs.…”

“…The positions of the 200−700 cm −1 modes (B 1 , B 2 , C 1 , C 2 , and C 3 bands) shift toward lower wavenumbers as the CTN content increases, a phenomenon related to the structural disorder factor and the increase in the size of the unit cell of the nonpolar phase with increasing doping content. 12 Therefore, the addition of CTN increases the ionic disorder, which is the key factor to breaking the long-range ferroelectric order and generating PNRs. In order to observe the evolution of the phase structure and local structure intuitively, transmission electron microscopy (TEM) measurements were performed on two representative samples with x = 0 and 0.4, as displayed in Figure 2.…”

“…Equations and clearly show that high W rec and η values can be achieved by increasing the polarization difference ( P m – P r ) and the dielectric breakdown strength ( E b ). According to the difference in the polarization-electric field curves, dielectrics can be classified into ferroelectric (FE), antiferroelectric (AFE), relaxor ferroelectric (RFE), and linear dielectrics. − FE materials usually have high dielectric constants, but their P r values are also large. AFE materials exhibit a critical electric field for the FE to AFE phase transition, resulting in double P – E loops, leading to lower η.…”

“…This kind of material is expected not only to dilute ferroelectric order for a slim P – E loop but also to increase the bandwidth for a large E b . For the latter case, linear dielectrics with wide band gaps, such as Ta 2 O 5 , , HfO 2 , MgO, CaTiO 3 , etc., have been proved to be excellent candidates to modify the band structure. In other words, band structure engineering should be another feasible strategy for high-performance energy storage properties.…”

Simultaneous achievement of ultrahigh energy storage density and high efficiency in BiFeO3-based relaxor ferroelectric ceramics via a highly disordered multicomponent design

“…† Fig. 5 compares the vital parameters for dielectric energy storage between the recently reported Bi 0.5 Na 0.5 TiO 3 (BNT)-, [29][30][31][32][33] BaTiO 3 (BT)-, 6,7,[34][35][36] (K 0.5 Na 0.5 )NbO 3 (KNN)-, 12,[37][38][39][40] BiFeO 3 (BFO)based 10,[13][14][15][16][17]24,27,41,42 relaxor ferroelectric ceramics and our case. The detailed composition, as well as the values of E test /E b , W rec and h are listed in Table S3.…”