Enhancing Energy Storage Performance in Lead-Free Bismuth Sodium Niobate-Based Tungsten Bronze Ceramics through Relaxor Tuning

Abstract

A series of tungsten bronze Sr2Na0.85Bi0.05Nb5–x Ta x O15 (SBNN-xTa) ferroelectric ceramics were designed and synthesized by the traditional solid-phase reaction method. The B-site engineering strategy was utilized to induce structural distortion, order–disorder distribution, and polarization modulation to enhance relaxor behavior. Through investigating the impact of B-site Ta replacement on the structure, relaxor behavior, and energy storage performance, this study has shed light on the two main factors for relaxor nature: (1) with the increase of Ta substitution, the tungsten bronze crystal distortion and expansion induced the structural change from an orthorhombic Im2a phase to Bbm2 phase at room temperature; (2) the transition from ferroelectric to relaxor behavior could be attributed to the coordinate incommensurate local superstructural modulations and the generation of nanodomain structure regions. Moreover, we benefited from the effective decrease of ceramic grains and inhibition of abnormal growth. Finally, we obtained an effective energy storage density (W rec) ∼ 1.6 J/cm3, an efficiency (η) ∼ 80%, a current density (C D) ∼ 1384.2 A/cm2, and a power density (P D) ∼ 138.4 MW/cm3.

Engineering Phase Separation in Niobate Glass through Ab Initio Molecular Dynamics for Enhanced Energy Storage Performance and Unprecedented Thermal Stability in Niobate-Based Glass Ceramics

“…It is noteworthy that the sample consistently exhibits slender P–E loops thanks to its robust thermal stability, the decrease in W rec and η remains below 3 and 4%, respectively, throughout the tested temperature range. In Figure i, a comparison of W rec and η between KBBNTP-2T GCs and various other tungsten bronze ceramics and glass ceramics is presented. − ,− Figure S13 also shows the stability of the KBBNTP-2T GCs sample in terms of different frequencies and cycle numbers. It can be seen that this sample shows a certain degree of stability.…”

Ultrahigh Energy Storage in Tungsten Bronze Dielectric Ceramics Through a Weakly Coupled Relaxor Design

“…[17][18][19][20][21][22][23][24][25][26][27][28][29][30] In Figure 1d, a comparison is made between the energy-storage performance of sample S2 with other TTBs ceramics. It is evident that sample S2, developed in the scope of this study, has the highest recoverable energy density W rec among all TTBs ceramics, [6,7,[13][14][15][31][32][33][34][35][36][37][38][39][40][41] reaching to a remarkable 9 J cm −3 .…”

“…[17][18][19][20][21][22][23][24][25][26][27][28][29][30] and d) W rec versus 𝜂 with other TTBs ceramics reported previously. [6,7,[13][14][15][31][32][33][34][35][36][37][38][39][40][41] e) Under-damped discharge waveforms of the S2 sample as a function of time, the inset shows the current density (C D ) and power discharge density (P D ) as a function of applied electric fields. f) Over-damped discharging current (I-t) curves of the S2 sample ceramic in connection with a fixed load resistance of 300 Ω under various electric fields, and the inset shows the discharge energy density (W D -t) curves.…”

“…b) calculated W rec and 𝜂 under E b from unipolar hysteresis loops. c) Comparison of the W rec versus 𝜂 of ceramic S2 with other representative lead-free ceramics reported previously[17][18][19][20][21][22][23][24][25][26][27][28][29][30] and d) W rec versus 𝜂 with other TTBs ceramics reported previously [6,7,[13][14][15][31][32][33][34][35][36][37][38][39][40][41]. e) Under-damped discharge waveforms of the S2 sample as a function of time, the inset shows the current density (C D ) and power discharge density (P D ) as a function of applied electric fields.…”

Achieving high energy density/efficiency in light-metal-element-rich relaxor ferroelectric ceramics by annihilating volatile Schottky defects

“…Apart from A-site doping, heavy ions doped into B sites, e.g., Hf and Ta, can enhance ESP properties from many perspectives, such as stabilizing the weakly polar/antiferroelectric state and rening the average grain size to increase E b . 12,18,19 In addition, the prevailing energy storage ceramic systems invariably contain heavy ions, such as (Pb, La)(Zr, Ti)O 3 , BiFeO 3 , (Bi, Na)TiO 3 , and BaTiO 3 . Thus, heavy elements are probably one of the sources of large ferroelectric polarization and excellent ESP.…”