title: Dielectric properties of lead-free BZT-KNN perovskite ceramics for energy storage.
abstract: Lead-free (1-x)Ba(Zr₀.₁₅Ti₀.₈₅)O₃-x(K₀.₅Na₀.₅)NbO₃ ; 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 % (K₀.₅Na₀.₅)NbO₃ to Ba(Zr₀.₁₅Ti₀.₈₅)O₃ improves the dielectric constant and enhances its diffuseness in a wide temperature range. The small amount of (K₀.₅Na₀.₅)NbO₃ is found to markedly affect the microstructure of the Ba(Zr₀.₁₅Ti₀.₈₅)O₃ 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(Zr₀.₁₅Ti₀.₈₅)O₃-x(K₀.₅Na₀.₅)NbO₃ (x=0-0.03; especially x=0.01) ceramics.
authors: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, PR China.
authors: Dong-Yun
authors: DY
authors: Gui
authors: Han-Xing
authors: HX
authors: Liu
authors: Hua
authors: H
authors: Hao
authors: Yue
authors: Y
authors: Sun
authors: Ming-He
authors: MH
authors: Cao
authors: Zhi-Yong
authors: ZY
authors: Yu
mesh_terms: D001464:Barium / Q000737:chemistry; D017610:Calcium Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D002254:Carbonates / Q000737:chemistry; D002516:Ceramics / Q000138:chemical synthesis / Q000737:chemistry*; D017097:Electric Impedance; D011211:Electric Power Supplies; D008855:Microscopy, Electron, Scanning; D009556:Niobium / Q000737:chemistry; D010087:Oxides / Q000138:chemical synthesis / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry; D033362:Powder Diffraction; D014025:Titanium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry
chemical_list: D017610:Calcium Compounds; D002254:Carbonates; D010087:Oxides; D009556:Niobium; C059910:perovskite; C009495:titanium dioxide; D001464:Barium; C005686:sodium carbonate; C006685:barium carbonate; C037593:potassium carbonate; D015040:Zirconium; D014025:Titanium; C073337:niobium pentoxide; D011188:Potassium; C028541:zirconium oxide