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Enhanced pyroelectric properties of lead‐free BNT‐BA‐KNN ceramics for thermal energy harvesting
Author(s) -
Shen Meng,
Qin Yanfeng,
Zhang Yujing,
Marwat Mohsin Ali,
Zhang Chao,
Wang Wanqiang,
Li Mingyu,
Zhang Haibo,
Zhang Guangzu,
Jiang Shenlin
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16250
Subject(s) - pyroelectricity , materials science , ferroelectricity , ceramic , tetragonal crystal system , phase transition , natural bond orbital , dielectric , microstructure , analytical chemistry (journal) , phase (matter) , mineralogy , composite material , thermodynamics , optoelectronics , chemistry , density functional theory , physics , computational chemistry , organic chemistry , chromatography
In this work, (1− x )(0.98Bi 0.5 Na 0.5 TiO 3 ‐0.02BiAlO 3 )‐ x (Na 0.5 K 0.5 )NbO 3 (BNT‐BA‐ x KNN) lead‐free pyroelectric ceramics were prepared by a solid‐state reaction method. The effect of Na 0.5 K 0.5 NbO 3 (KNN) content on microstructure, phase transition, and electrical properties of the BNT‐BA‐ x KNN ceramics were systematically investigated. The results show that the appropriate content of KNN can induce the formation of the tetragonal structure, which results in the decreased ferroelectric‐antiferroelectric phase transition temperature as a result of the break of long‐range translational symmetry of BNT lattices. Therefore, the ferroelectric and pyroelectric properties of the BNT‐BA‐ x KNN near room temperature are improved. The room‐temperature pyroelectric coefficient significantly increases from 3.66 × 10 −4 C/m 2 /K at x = 0 to 8.04 × 10 −4 C/m 2 /K at x = 0.02, making a great contribution to the superior pyroelectric energy harvesting. The output energy density in one cycle of the BNT‐BA‐0.02KNN is 23.32 μJ/cm 3 , which is twice as high as that of the pristine samples. The enhancement of material properties suggests that the pyroelectric energy harvesting can be efficiently optimized by the adequate control of the phase structure.