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Dielectric Properties of Lead‐Free BZT–KNN Perovskite Ceramics for Energy Storage
Author(s) -
Gui DongYun,
Liu HanXing,
Hao Hua,
Sun Yue,
Cao MingHe,
Yu ZhiYong
Publication year - 2011
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201100451
Subject(s) - materials science , natural bond orbital , microstructure , dielectric , perovskite (structure) , analytical chemistry (journal) , ceramic , grain size , scanning electron microscope , mineralogy , crystallography , chemistry , composite material , density functional theory , computational chemistry , optoelectronics , chromatography
Lead‐free (1− x )Ba(Zr 0.15 Ti 0.85 )O 3 – x (K 0.5 Na 0.5 )NbO 3 ; x =0–0.05) (BZT–KNN) perovskite ceramics, a materials with potential applications for energy storage, are investigated. The samples are prepared by a solid‐state reaction method. Powder X‐ray diffraction (XRD) and scanning electron microscopy (SEM) are used to study the microstructure of the samples. Their dielectric properties and impedance spectra are reported as functions of temperature and frequency. The addition of 1 mol % (K 0.5 Na 0.5 )NbO 3 to Ba(Zr 0.15 Ti 0.85 )O 3 improves the dielectric constant and enhances its diffuseness in a wide temperature range. The small amount of (K 0.5 Na 0.5 )NbO 3 is found to markedly affect the microstructure of the Ba(Zr 0.15 Ti 0.85 )O 3 ceramic (grain size and other characteristics) without changing the phase or crystal symmetry. In addition, we report that fine substructures in the grains, so‐called sheet structures, are responsible for the dielectric properties (both diffuseness and dielectric constant) of (1−x)Ba(Zr 0.15 Ti 0.85 )O 3 – x (K 0.5 Na 0.5 )NbO 3 ( x =0–0.03; especially x =0.01) ceramics.