Electrostatic energy storage performances of La(Ni_2/3Ta_1/3)O₃‐modified Na_0.5Bi_0.5TiO₃ lead‐free ceramics

Abstract

Ceramic capacitors with high electrostatic energy storage performances have captured much research interest in latest years. Sodium bismuth titanate (Na0.5Bi0.5TiO3)‐based ferroelectric ceramics show great potential due to their environment‐friendly composition, high polarization, and excellent relaxor properties. However, the nonergodic relaxor state of Na0.5Bi0.5TiO3‐based ceramics hampers the decrement of remanent polarization, leading to poor energy storage performance. Herein, the (1 − x)Na0.5Bi0.5TiO3–xLa(Ni2/3Ta1/3)O3 ceramics were designed to generate the transformation between nonergodic and ergodic relaxor state. As a result, the ceramics exhibit improved dielectric relaxation, slim polarization–electric field loops, and flattened current–electric field curves due to highly dynamic polar nanoregions. Particularly, the 0.85Na0.5Bi0.5TiO3–0.15La(Ni2/3Ta1/3)O3 ceramics show large breakdown electric field Eb (345 kV/cm), high recoverable energy density Wrec (3.6 J/cm3), and efficiency η (80.6%), revealing potential applications in electrostatic energy storage.

Prominent energy storage density and efficiency of Na0.5Bi0.5TiO3‐based ceramics via multiscale amelioration strategy

“…17,46,47 The decrease of tanδ is conducive to reducing energy loss and improving η. 48 To analyze the relaxation behavior in depth, the diffusion factor (γ) is often used to describe the degree of relaxation, which is calculated by the following formula 49 :…”

“…Obviously, with the increase of SANT, the saturation polarization is delayed and the P-E loops are refined, which can be attributed to the destruction of long-range ferroelectric order and the formation of PNRs, resulting in the fast response of small-sized domain. 48,51 In addition, the value of W rec , W t and η for 0.84NBLBT-0.16SANT ceramic at different electric fields are shown in Figure 7(B). With the increase of applied electric fields, the value of W rec gradually raises.…”

“…This situation can be attributed to the fast response of small-sized domain. 17,48 In addition, Figure 8(B) and (D) shows the P-E loops, W rec and η of 0.84NBLBT-0.16SANT ceramic at different temperatures. With the temperature rises from 20 to 140 • C, the P-E loops remain slim, and the P m slightly reduces.…”

Effect of La substitution on energy storage properties of (Bi0.2Na0.2Ca0.2Ba0.2Sr0.2)TiO3 lead‐free high‐entropy ceramics

“…27 In addition, the long-range ferroelectric order can be severely disrupted through La doping, which will contribute to the promotion of ergodicity degree and energy storage performance. [28][29][30][31] Zhang et al reported that the ergodic degree deepened with La content in a La-doped 0.93(Na 0.5 Bi 0.5 )TiO 3 -0.07Ba(Zr 0.055 Ti 0.945 )O 3 system, which resulted in "slimmer" P-E loops and enhanced η and W rec . 29 Yu et al added La to 0.78Na 0.5 Bi 0.5 TiO 3 -0.22K 0.5 Bi 0.5 TiO 3 ceramics and discovered that the ferroelectric order was largely disrupted by La doping and converted to an ergodic relaxation state.…”

“…synthesized lead‐free La‐substituted 0.72Na0.5Bi0.5TiO3‐0.28Sr0.7Bi0.2TiO3 and showed that La addition effectively decreased the grain size and generated a large E b , achieving the optimum W rec (1.2 J/cm 3 ) for 0.005La‐substituted ceramic under an E b of 90 kV/cm 27 . In addition, the long‐range ferroelectric order can be severely disrupted through La doping, which will contribute to the promotion of ergodicity degree and energy storage performance 28–31 . Zhang et al.…”