Multiphase Engineered BNT-Based Ceramics with Simultaneous High Polarization and Superior Breakdown Strength for Energy Storage Applications

Abstract

Dielectric ceramics are crucial for high-temperature, pulse-power energy storage applications. However, the mutual restriction between the polarization and breakdown strength has been a significant challenge. Here, multiphase engineering controlled by the two-step sintering heating rate is adopted to simultaneously obtain a high polarization and breakdown strength in 0.8(0.95Bi 0.5 Na 0.5 TiO 3 − 0.05SrZrO 3 )−0.2NaNbO 3 (BNTSZNN) ceramic systems. The coexistence of tetragonal (T) and rhombohedral (R) phases benefits the temperature stability of BNTSZNN ceramics. Increasing the heating rate during sintering reduces the diffusion of SrZrO 3 and NaNbO 3 into Bi 0.5 Na 0.5 TiO 3 , which results in a high proportion of the R phase and a finer grain size. The overall polarization is enhanced by increasing the proportion of the high-polarization R phase, which is demonstrated using a first-principles method. Meanwhile, the finer grain size enhances the breakdown strength. Following this design philosophy, an ultrahigh W dis of 5.55 J/cm 3 and η above 85% is achieved in BNTSZNN ceramics as prepared with a fast heating rate of 60 °C/min given a simultaneously high polarization of 43 μC/cm 2 and high breakdown strength of 350 kV/cm. Variations in the discharge energy density from room temperature to 160 °C are less than 10%. Additionally, such BNTSZNN ceramics exhibit an ultrafast discharge speed with τ 0.9 at approximately 60 ns, which shows great potential in pulse-power system applications.

Simultaneously enhanced energy density and discharge efficiency of (Na0.5Bi0.5)0.7Sr0.3TiO3-La1/3(Ta0.5Nb0.5)O3 lead-free energy storage ceramics via grain inhibition and dielectric peak flattening engineering

“…8(d). Compared with NN-based, 47,48 BNT-based, [49][50][51][52][53][54][55][56] BT-based [57][58][59] and BF-based 60,61 ceramics under analogously low electric fields, the BNST-0.025LTN ceramic exhibits an appreciable W rec accompanied by an ultrahigh η. Obviously, the present study tenders an effective strategy to obtain a simultaneous elevation of W rec and η at low electric fields, which is competitive in practical applications of dielectric materials.…”

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.…”

Energy storage performance of BiFeO3–SrTiO3–BaTiO3 relaxor ferroelectric ceramics

“…1 Hence, the large or small ε r will lead to electromechanical breakdown for dielectric ceramics under high electric fields. [1][2][3][4] In order to describe the relaxor behavior of (0.55−x)BFO-0.45STO-xBTO ceramics quantitatively, the modified Curie-Weiss law is employed based on following equation: [20][21][22]…”

“…Generally, γ = 1 represents a normal ferroelectric material, while γ = 2 indicates ideal relaxor ferroelectrics. [20][21][22] The fitting results are presented in Figure 4a, and the composition-dependent γ is plotted in Figure 4b. The linear relationship between ln(1/ε−1/ε r ) and ln(T-T m ) suggests the reliability of fitting results, and the γ increases from 1.68 for x = 0 to the value larger than 1.9 for x > 0.05, which further confirms the enhancement of relaxor properties.…”

“…In order to describe the relaxor behavior of (0.55− x )BFO–0.45STO– x BTO ceramics quantitatively, the modified Curie‐Weiss law is employed based on following equation: 20–22 $$\begin{equation}\frac{1}{{{\varepsilon _r}}} - \;\frac{1}{{{\varepsilon _{r,max}}}} = \frac{{{{\left( {T - {T_m}} \right)}^\gamma }}}{C}\;(T > {T_m})\end{equation}$$where γ is the diffusion degree, C is the Curie‐Weiss constant. Generally, γ = 1 represents a normal ferroelectric material, while γ = 2 indicates ideal relaxor ferroelectrics 20–22 . The fitting results are presented in Figure 4a, and the composition‐dependent γ is plotted in Figure 4b.…”