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 (d33) increased as the thickness of the porous layer and total porosity level of the layered structure increased. The permittivity () 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, , for the layered structure, with a maximum of 3.74 pm2/N when the relative thickness of the porous layer was 0.52 and the porosity within this layer was ∼60 vol%. This harvesting performance of these novel structures is much larger than both dense barium titanate (1.40 pm2/N) and barium titanate with randomly distributed porosity at the same 60% volume fraction (2.75 pm2/N).
|Number of pages||11|
|Early online date||10 Feb 2017|
|Publication status||Published - 15 Apr 2017|
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- Department of Mechanical Engineering - Professor
- Centre for Sustainable and Circular Technologies (CSCT)
- Centre for Nanoscience and Nanotechnology
- Institute for Mathematical Innovation (IMI)
- Faculty of Engineering and Design - Associate Dean (Research)
- Institute for Sustainability
- Centre for Integrated Materials, Processes & Structures (IMPS)
- EPSRC Centre for Doctoral Training in Advanced Automotive Propulsion Systems (AAPS CDT)
- Institute for Advanced Automotive Propulsion Systems (IAAPS)
Person: Research & Teaching, Core staff, Affiliate staff
- Department of Electronic & Electrical Engineering - Professor
- Electronics Materials, Circuits & Systems Research Unit (EMaCS)
Person: Research & Teaching
Dataset for 'Modelling and fabrication of porous sandwich layer barium titanate with improved piezoelectric energy harvesting figures of merit'
Roscow, J. (Creator), Lewis, R. (Creator), Taylor, J. (Creator) & Bowen, C. (Creator), University of Bath, 2017