Modelling and fabrication of porous sandwich layer barium titanate with improved piezoelectric energy harvesting figures of merit
Modelling and fabrication of porous sandwich layer barium titanate with improved piezoelectric energy harvesting figures of merit
复制标题
DOI：
10.1016/j.actamat.2017.02.029
复制
发表时间：
2017-04-15
期刊：
影响因子：
9.4
通讯作者：
Bowen, C. R.
中科院分区：
文献类型：
--
作者：
Roscow, J. I.;Lewis, R. W. C.;Bowen, C. R.
本文证明了多孔"三明治"结构可以为能量收集应用的压电材料的设计和优化提供有效的途径，这正在成为自供电无线网络和传感器越来越重要的技术。一个数值模型，占整个层状铁电体的复杂的极化分布，并有助于开发一个详细的了解多孔结构的几何形状和多孔铁电材料的极化特性之间的关系，与实验数据吻合良好。新型层状钛酸钡陶瓷的制造，其中致密的外层包围一个高度多孔的三明治层，并为特定的层的几何形状，实现了一个不寻常的条件下，纵向压电应变系数（d（33））增加的多孔层的厚度和总孔隙率水平的层状结构的增加。由于低介电常数空气相的存在，介电常数（ε（T）（33））随着多孔层的厚度增加和孔隙率水平增加而降低。这两个因素结合导致层状结构的纵向能量收集优值d（33）（2）/μ m（T）（33）增加，当多孔层的相对厚度为0.52且该层内的孔隙率类似于60体积%时，最大值为3.74 μ m（2）/N。这些新颖结构的这种收获性能比致密钛酸钡（1.40 μ m（2）/N）和具有相同60%体积分数的随机分布孔隙率的钛酸钡（2.75 μ m（2）/N）两者大得多。(C)2017 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
This paper demonstrates that porous 'sandwich' structures can provide an effective route for the design and optimisation of piezoelectric materials for energy harvesting applications, which is becoming an increasingly important technology for self -powered wireless networks and sensors. A numerical model is presented that accounts for the complex poling distribution throughout a layered ferroelectric and helps to develop a detailed understanding of the relationship between the geometry of the porous structure and the poling characteristics of porous ferroelectric materials, with good agreement with experimental data. Novel layered barium titanate ceramics were fabricated whereby dense outer layers surround a highly porous sandwich layer, and for specific layer geometries an unusual condition was achieved where the longitudinal piezoelectric strain coefficients (d(33)) increased as the thickness of the porous layer and total porosity level of the layered structure increased. The permittivity (epsilon(T)(33)) decreased with increasing thickness and increasing porosity level of the porous layer due to the presence of a low permittivity air phase. These two factors in combination led to an increase in the longitudinal energy harvesting figure of merit, d(33)(2)/epsilon(T)(33), for the layered structure, with a maximum of 3.74 pm(2)/N when the relative thickness of the porous layer was 0.52 and the porosity within this layer was similar to 60 vol%. This harvesting performance of these novel structures is much larger than both dense barium titanate (1.40 pm(2)/N) and barium titanate with randomly distributed porosity at the same 60% volume fraction (2.75 pm(2)/N). (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.