Abstract
This paper demonstrates the significant benefits of exploiting highly aligned porosity in piezoelectric and pyroelectric materials for improved energy harvesting performance. Porous lead zirconate (PZT) ceramics with aligned pore channels and varying fractions of porosity were manufactured in a water-based suspension using freeze-casting. The aligned porous PZT ceramics were characterized in detail for both piezoelectric and pyroelectric properties and their energy harvesting performance figures of merit were assessed parallel and perpendicular to the freezing direction. As a result of the introduction of porosity into the ceramic microstructure, high piezoelectric and pyroelectric harvesting figures of merits were achieved for porous freeze-cast PZT compared to dense PZT due to the reduced permittivity and volume specific heat capacity. Experimental results were compared to parallel and series analytical models with good agreement and the PZT with porosity aligned parallel to the freezing direction exhibited the highest piezoelectric and pyroelectric harvesting response; this was a result of the enhanced interconnectivity of the ferroelectric material along the poling direction and reduced fraction of unpoled material that leads to a higher polarization. A complete thermal energy harvesting system, composed of a parallel-aligned PZT harvester element and an AC/DC converter, was successfully demonstrated by charging a storage capacitor. The maximum energy density generated by the 60 vol% porous parallel-connected PZT when subjected to thermal oscillations was 1653 μJ cm−3, which was 374% higher than that of the dense PZT with an energy density of 446 μJ cm−3. The results are beneficial for the design and manufacture of high performance porous pyroelectric and piezoelectric materials in devices for energy harvesting and sensor applications.
Original language | English |
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Pages (from-to) | 6569-6580 |
Number of pages | 12 |
Journal | Journal of Materials Chemistry A |
Volume | 5 |
Issue number | 14 |
Early online date | 6 Mar 2017 |
DOIs | |
Publication status | Published - 14 Apr 2017 |
ASJC Scopus subject areas
- General Chemistry
- Renewable Energy, Sustainability and the Environment
- General Materials Science
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Chris Bowen
- Department of Mechanical Engineering - Professor
- Faculty of Engineering and Design - Associate Dean (Research)
- Centre for Sustainable Chemical Technologies (CSCT)
- Centre for Nanoscience and Nanotechnology
- Institute for Mathematical Innovation (IMI)
- Institute of Sustainability and Climate Change
- Centre for Integrated Materials, Processes & Structures (IMPS)
- IAAPS: Propulsion and Mobility
Person: Research & Teaching, Core staff, Affiliate staff