Enhanced Electrocaloric Effect and Energy Storage Density of Nd‐Substituted 0.92NBT‐0.08BT Lead Free Ceramic

Abstract

Eco‐friendly 0.92(Na0.5Bi0.49Nd0.01TiO3)‐0.08(BaTiO3) [denoted as NBNT‐BT 92/8] ceramic is synthesized with the help of conventional solid state reaction route. The structural phase pure studies reveals, the compound stabilizes into mixed phase of Cc + P4 mm and the surface morphology of microstructure shows the uniform distribution of Nd. The temperature dependent dielectric study reveals two typical anomalies with the diffuse phase transition and show the relaxor future estimated with the help of diffusivity (γ). From the temperature dependent polarization and room temperature bipolar strain hysteresis loops over broad electrical field range from (0–73) kV cm−1, the estimated energy storage density, energy storage efficiency, and strain values are Wrec ≈ 1.53J cm−3, η ≈ 93(%), and S(%) ≈ 0.4, respectively, which is the best obtained value among available various reported lead‐free piezoelectric ceramics. The adiabatic or electrocaloric temperature change (ΔT) is calculated to be ΔT ≈ 0.95 K at 50 kV cm−1. The obtained valued of ΔT, strain and energy storage density for NBNT‐BT 92/8 is tremendous enhancement compared with absence of Nd in NBT‐BT 92/8.

Nd3+ and Nb5+ Co‐Substitution Inducing a Large Electrocaloric Response in Na0.5Bi0.5TiO3 Lead‐Free Ceramics

“…While for NBNT‐Nb‐1 ceramics (shown Figure (red color)), I–E loop exhibits four distinct peaks at ± E F ( E F = 55.24 kV cm −1 ) and ± E 1 ( E 1 = 25.40 kV cm −1 ). The peak at + E F represents a transition from part of antiferroelectric (AFE) phase to ferroelectric (FE) phase when the ceramics are applied by a positive electric field . It is well reported in NBT based ceramics, the tetragonal phase shows antiferroelectric characteristics while rhombohedral and/or monoclinic phase is ferroelectric characteristics.…”

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

“…where ρ is the density of samples offered in Figure 2e, C E is the specific heat at constant electric field (obtained from literature [34]), and (∂P/∂T) E represents the variation rate of polarization versus test temperature under constant electric field. Since only the P-E loops at limited temperatures have been measured, (∂P/∂T) E should be obtained by derivation of P-T polynomial fitting curves.…”

Structure and Electrical Properties of Morphotropic Phase Boundary (Na1/2Bi1/2)TiO3‐PbTiO3‐Bi(Mg1/2Ti1/2)O3 Ternary System

“…Recently, many research groups have focused on the development of new, environmentally benign piezoelectric materials as potential replacements for lead zirconate titanate [Pb(Zr x Ti 1−x )O 3 or PZT] and its related solid solutions. For example, Bi 0.5 Na 0.5 TiO 3 ‐based solid solutions, K 0.5 Na 0.5 NbO 3 ‐based systems, and (1−x)Ba(Ti 0.8 Zr 0.2 )O 3 −x(Ba 0.7 Ca 0.3 )TiO 3 perovskite lead‐free piezoceramics were widely investigated . However, the development of lead‐free piezoceramics has not been advanced to a level where it can replace the Pb‐based piezoceramics for commercial applications.…”

“…For example, Bi 0.5 Na 0.5 TiO 3 -based solid solutions, K 0.5 Na 0.5 NbO 3 -based systems, and (1Àx)Ba(Ti 0.8 Zr 0.2 )O 3 Àx(Ba 0.7 Ca 0.3 )TiO 3 perovskite lead-free piezoceramics were widely investigated. [1][2][3][4][5][6][7][8][9][10] However, the development of lead-free piezoceramics has not been advanced to a level where it can replace the Pb-based piezoceramics for commercial applications. There is still a lack of fundamental understanding of the structure-property relations and mechanism for high piezoelectric response.…”

“…It is well known that the MPB plays a very important role in PZT ceramics because the piezoelectric and dielectric properties show a maximum over a specific compositional range around the MPB . Similar to PZT, high piezoelectric coefficient and ultrahigh strain are observed in other Pb‐based and lead‐free MPB systems such as (1−x)Pb(Mg 1/3 Nb 1/3 )O 3 −xPbTiO 3 , (1−x)Pb(Zn 1/3 Nb 1/3 )O 3 −xPbTiO 3 , (1−x)Bi 0.5 Na 0.5 TiO 3 −xBi 0.5 K 0.5 TiO 3 , (1−x)Bi 0.5 Na 0.5 TiO 3 −xBaTiO 3 , etc. In 2000, Noheda et al discovered monoclinic phase in a PbZr 0.52 Ti 0.48 O 3 sample by high‐resolution synchrotron X‐ray powder diffraction measurements, which is attributed to the high piezoelectric response of these materials for the compositions around MPB .…”