AUTHOR=Ji Hongfen , Xin Lipeng , Ma Han , Liu Weiguo , Dai Zhonghua , Pang Lixia , Xie Jinglong , Chen Zhaobin 

TITLE=Simultaneously Enhancing Thermal Stable Dielectric Property and Piezoelectric Response in Lead-Free LiNbO3-Modified (K0.5Na0.5)NbO3- (BaNi0.5Nb0.5O3) System

JOURNAL=Frontiers in Materials

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2020.00013

DOI=10.3389/fmats.2020.00013

ISSN=2296-8016

ABSTRACT=<p>Perovskite ferroelectic oxides with simultaneous highly thermal stable dielectric property and piezoelectric response are promising candidate for advanced energy, dielectric, and smart devices. The (1-x)[0.98[(K<sub>0.5</sub>Na<sub>0.5</sub>)NbO<sub>3</sub>]-0.02(BaNi<sub>0.5</sub>Nb<sub>0.5</sub>O<sub>3</sub>)]-xLiNbO<sub>3</sub> (abbreviated as (1-x)KNBNNO-xLiNbO<sub>3</sub>; x = 0.00, 0.02, 0.04, 0.06, 0.08) lead-free multifunction ferroelectric ceramic is synthesized by solid-state reaction method. XRD analysis reveals that the samples exhibit perovskite structure with 0 ≤ x ≤ 0.06, and the second phase K<sub>3</sub>Li<sub>2</sub>Nb<sub>5</sub>O<sub>15</sub> appears at x = 0.08. The scanning electron microscopy image show that the grain size of ceramics increases from 0.65 to 3.58 μm with LiNbO<sub>3</sub> content increasing. Meanwhile, the Curie temperature (<italic>T</italic><sub><italic>C</italic></sub>) shifts to a higher temperature (~ 427°C for x = 0.06). A high dielectric thermal stability of Δε/<inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mo>ε</mml:mo></mml:mrow><mml:mrow><mml:mn>4</mml:mn><mml:msup><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mrow><mml:mo>°</mml:mo></mml:mrow></mml:msup><mml:mtext>C</mml:mtext></mml:mrow></mml:msub></mml:math></inline-formula> ≤ ±10%, with a high dielectric permittivity (~1,400), is achieved at x = 0.06 over a wide temperature range of ~40–348°C with <italic>d</italic><sub>33</sub> of ~160 pC·N<sup>−1</sup>, and a remnant polarization (<italic>P</italic><sub>r</sub>) of 20.5 μC·cm<sup>−2</sup>. This work shows that this multifunction material could be applied in sensor to efficiently covert both solar and kinetic energies into electricity over a wide temperature range.</p>