Phase-transition induced optimization of electrostrain, electrocaloric refrigeration and energy storage of LiNbO3 doped BNT-BT ceramics

Abstract

abbreviated as LiNbO3-doped BNT-BT) ceramics possessing many excellent performances (large electrostrain, negative electrocaloric effect and energy storage density with high efficiency) was fabricated by the conventional solid-state reaction method. A large electrostrain (maximum ~ 0.34% at 100 kV/cm and room temperature) with high thermal stability over a broad temperature range (~ 80 K) is obtained at x = 0.03. A large energy storage density (maximum Wenergy ~ 0.665 J/cm 3 at 100 kV/cm and room temperature) with a high efficiency ( ~ 49.3%) is achieved at x = 0.06. Moreover, a large negative electrocaloric (EC) effect (maximum ΔT ~ 1.71 K with ΔS ~-0.22 J/(K kg) at 70 kV/cm)) is also obtained at x = 0.04. Phase transition (from ferroelectric to antiferroelectric and then to relaxor) induced by increasing the doping amount of LiNbO3 plays a very key role on the optimization of these performances. These findings and breakthroughs make the LiNbO3-doped BNT-BT ceramics very promising candidates as multifunctional materials.

Comparing the electromechanical properties of CaTiO3‐ and BaZrO3‐modified Bi0.5Na0.5TiO3–SrTiO3 ceramics

“…In the MPB (I) boundary, the coexistence of ferroelectric rhombohedral and tetragonal phases results in the significant piezoelectricity which can be obtained in (1 − x)BNT-xBaTiO 3 (BNT-BT) and (1 − x)BNT-x(Bi 0.5 K 0.5 )TiO 3 (BNKT) material systems [9,10]. By contrast, the MPB(II) boundary involves a phase transition from ferroelectric to antiferroelectric or from ferroelectric to relaxor ferroelectric (FE-RFE), is temperature-dependent, and has recently received significant attention due to its high electromechanical strain properties [8,11,12,13,14,15,16,17,18]. Currently, the solid solution (1 − x)BNT-xSrTiO 3 (BNST) is considered to be an important binary system among BNT-based ceramics and is reported to form a rhombohedral ferroelectric and pseudocubic MPB at x = 0.24-0.28 that results in an ultra-high strain of 0.25% and normalized strain (S max /E max ) of 600 pm/V [14,15,19,20,21].…”

Energy Storage and Electrocaloric Cooling Performance of Advanced Dielectrics

“…It can be concluded that the (1−x)LLBNTZ-xNBN ceramics are promising lead-free candidate materials for energy storage devices over a broad temperature range [ 53 ]. Zhang et al prepared ((Bi 0.5 Na 0.5 TiO 3 ) 0.88 -(BaTiO 3 ) 0.12 ) 1−x -(LiNbO 3 ) x (x = 0.0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06 and 0.07) by solid-phase reaction ceramics [ 54 ] ( Figure 9 ). BNT-BT ceramics achieved high thermal stability in the temperature range of approximately 80 K at x = 0.03; at x = 0.06, η ~49.3% and W rec ~0.665 J/cm 3 at a breakdown field strength of 100 kV/cm ( Figure 10 ).…”

“…PE, AFE and FE represent paraelectric, antiferroelectric and ferroelectric phase, respectively. Reprinted with permission from [ 54 ]. Copyright 2019 Elsevier Ltd. and Techna Group S.r.l.…”

“…( a ) W energy , ( b ) η , ( c ) W loss ( d ) W energy /W loss . Reprinted with permission from [ 54 ]. Copyright 2019 Elsevier Ltd. and Techna Group S.r.l.…”

Improved Non-Piezoelectric Electric Properties Based on La Modulated Ferroelectric-Ergodic Relaxor Transition in (Bi0.5Na0.5)TiO3-Ba(Ti, Zr)O3 Ceramics

“…Inasmuch as more defects decrease the electric breakdown field strength, the enhanced ECE of bulks should rationally resort to higher entropy change induced by order-disorder phase transition, rather than stronger applied electric field as performed in thin films. Under a driving electric field of 7 kV/mm, Zhang et al studied a small amount of LiNbO 3 modified 0.88(Na 1/2 Bi 1/2 )TiO 3 -0.12BaTiO 3 ceramics and obtained an improved ∆T = 1.71 K of ECE [13]. Wang et al incorporated (Bi 0.5 K 0.5 )TiO 3 (BKT) into BNT ceramics to prepare an optimized component achieving ∆T = 1.08 K of ECE [14].…”