Superior Thermal Stability of High Energy Density and Power Density in Domain-Engineered Bi_0.5Na_0.5TiO₃–NaTaO₃ Relaxor Ferroelectrics

Abstract

Thermal-stable dielectric capacitors with high energy density and power density have attracted increasing attention in recent years. In this work, (1 – x)­Bi0.5Na0.5TiO3–xNaTaO3 [(1 – x)­BNT–xNT, x = 0–0.30] lead-free relaxor ferroelectric ceramics are developed for capacitor applications. The x = 0.20 ceramic exhibits superior thermal stability of discharged energy density (W D) with a variation of less than 10% in an ultrawide temperature range of −50 to 300 °C, showing a significant advantage compared with the previously reported ceramic systems. The W D reaches 4.21 J/cm3 under 38 kV/mm at room temperature. Besides, a record high of power density (P D ≈ 89.5 MW/cm3) in BNT-based ceramics is also achieved in x = 0.20 ceramic with an excellent temperature insensitivity within 25–160 °C. The x = 0.20 ceramic is indicated to be an ergodic relaxor ferroelectric with coexisted R3c nanodomains and P4bm polar nanoregions at room temperature, greatly inducing large maximum polarization, maintaining low remnant polarization, and thus achieving high W D and P D. Furthermore, the diffuse phase transition from R3c to P4bm phase on heating is considered to be responsible for the superior thermal stability of the high W D and P D. These results imply the large potential of the 0.80BNT–0.20NT ceramic in temperature-stable dielectric capacitor applications.

High‐energy storage density in NaNbO3‐modified (Bi0.5Na0.5)TiO3‐BiAlO3‐based lead‐free ceramics under low electric field

“…It can be seen that x = 0.14 sample exhibits excellent responsivity with ξ = 130.69 J/ (kV⋅m 2 ), which is superior to most other reported lead-free ceramics. 4,6,15,19,20,26,27,[45][46][47][48][49] To evaluate the temperature stability of energy storage properties, Figure 10 presents P-E loops of x = 0.14 composition measured in the temperature range of 30°C-180°C under 1 Hz and 10 kV/mm. Figure 10B temperature-dependent W rec and η.…”

“…Compared with batteries and electrochemical capacitors, dielectric capacitors possess higher power density and faster charge–discharge capabilities 1 . Particularly, the ceramic‐based dielectric capacitor also exhibit excellent temperature stability 4‐6 . Therefore, they have receive extensive attention and investigated widely.…”

“…1 Particularly, the ceramicbased dielectric capacitor also exhibit excellent temperature stability. [4][5][6] Therefore, they have receive extensive attention and investigated widely. Generally, for the dielectric ceramics, the parameters to characterize the energy storage can be calculated by the equation 1 : W rec ∫ P max P r EdP, W s ∫ P max 0 EdP, = W rec W s × 100%, where P max , P r , E, W rec , W s , η denote the maximum polarization, remnant polarization, applied electric field, recoverable energy storage density, stored energy storage density, and energy storage efficiency, respectively.…”

Perspectives and challenges for lead-free energy-storage multilayer ceramic capacitors

“…Notably, the BNT-based relaxor ceramics are considered to be promising for thermally-stable dielectric capacitor applications because of their diffuse phase transition behavior. Zhou et al [71] developed an ergodic relaxor ferroelectric composed of 0.8Bi 0.5 Na 0.5 TiO 3 -0.2NaTaO 3 (0.8BNT-0.2NT), exhibiting the superior temperature stability of rec W with a variation of < 10% over an ultrawide temperature range from −50 to 300 ℃. Zhu et al [72] chose NN to modify 0.95BNT-0.05SZ and realized coexistence of the rhombohedral (R) and tetragonal (T) phases.…”

High energy storage density and efficiency with excellent temperature and frequency stabilities under low operating field achieved in Ag0.91Sm0.03NbO3-modified Na0.5Bi0.5TiO3-BaTiO3 ceramics

“…Most recently, a large number of lead-free relaxor ferroelectric ceramics with high energy storage density have been developed [31][32][33][34][35][36][37][38][39][40]. For example, Yuan et al [31] successfully prepared the 0.85BaTiO 3 -0.15Bi(Mg 0.5 Zr 0.5 ) O 3 ceramics with high breakdown electric field (30.14 kV/ mm) and low P r (< 1.64 μC/cm 2 ).…”