Projects / Programmes
Domain engineered ferroelectric ceramic layer elements for efficient energy harvesting and energy conversion applications
| Code |
Science |
Field |
Subfield |
| 2.09.01 |
Engineering sciences and technologies |
Electronic components and technologies |
Materials for electronic components |
| Code |
Science |
Field |
| T153 |
Technological sciences |
Ceramic materials and powders |
| Code |
Science |
Field |
| 2.05 |
Engineering and Technology |
Materials engineering |
electrocalorics, microelectromechanical systems, ceramics, energy conversion, energy harvesting
Researchers (25)
Organisations (3)
Abstract
Requirements such as multi-functionality, the use of environmentally friendly materials and processes, reduced levels of energy consumption, are now very important considerations, coming on top of the classic requirements for electronics, such as miniaturization, higher efficiency, reliability, complexity of the electronic components. This is reflected in the search for ceramic materials with excellent, reproducible and stable functional properties. Ceramic ferroelectrics and relaxor-ferroelectrics with a perovskite structure exhibit excellent functional properties, such as a large permittivity, piezoelectricity, ferroelectricity, which means that they can be employed as capacitors, sensors, actuators, transducers, as well as for energy harvesting, and in recent year potentially also as cooling elements in electrocaloric cooling technologies.
Our goal is to fabricate demonstrators for two groups of applications: for efficient piezoelectric energy harvesting and for energy conversion via the electrocaloric effect. Materials which exhibit optimum piezoelectric or electrocaloric properties are chemically very similar, they are complex perovskite compounds or solid solutions, typically with different cations occupying the same crystal lattice site. We will consider material compositions with good piezoelectric properties, suitable for energy harvesting, and also compositions which exhibit large electrocaloric temperature changes close to room temperature and could be applied in cooling devices. In both applications the ceramic elements have a similar geometry of thin plates with electrodes deposited on the faces. We will use multilayers, prepared by tape-casting, which will allow us to achieve a higher efficiency or lower applied voltages, as the thickness of an individual layer is much less than the thickness of bulk ceramic plates.
Due to environmental concerns lead-free complex perovskites will be investigated in the project, while highly efficient established lead-based ferroelectrics will be studied as reference. We will prepare and study selected materials with excellent piezoelectric properties, suitable for piezoelectric energy harvesting as well as materials which exhibit large electrocaloric temperature changes and are suitable for cooling applications. We will investigate whether and how a selected powder synthesis route, mechanochemical or solid-state, influences the elements of the microstructure of the studied materials, specifically the domain structure, and consequently their functional properties. We will enhance functional properties of the studied materials by domain engineering. Finally, we will fabricate two demonstrators by using the multilayers, prepared by tape-casting: vibrational energy harvester and electrocaloric cooling elements.
Significance for science
Perovskite ferroelectrics and relaxor-ferroelectrics are materials of immense opportunities, as they exhibit an extraordinary range of properties which find applications in our lives. In our project we focus on the study of perovskite materials with two groups of functional properties, electromechanical and electrocaloric, suitable for applications in energy harvesting and electrocaloric cooling, respectively. Improving the performance of perovskite ferroelectric materials is usually achieved by chemical modification, or doping. In our case we plan to investigate whether and how the choice of the synthetic approach influences the microstructure descriptors, specifically the domain structure of complex perovskite materials, and consequently their functional properties. Investigations of the latter properties will be performed locally, mainly by piezo-force microscopy, and macroscopically, by electrical measurements. The knowledge on processing – properties relation will be implemented in fabrication of efficient demonstrators, vibrational energy harvester and electrocaloric cooling elements.
We plan to publish the results of the research project in high-impact journals and present them at national and international scientific meetings. The students will also be included in the project gaining new knowledge on functional materials for energy harvesting and cooling applications.
To conclude, in the scientific community there is almost no understanding how the synthetic approach, microstructure and especially domain structure influence the electrocaloric properties of materials. Therefore, this part of the study will represent original contributions to the field. But we will go even further; we will contribute to the field also with knowledge on efficient demonstrators.
Significance for the country
The goal of the project is to fabricate ferroelectric ceramic (multi)layer elements for efficient energy harvesting / energy conversion applications. Both fields of applications are important for our society which is increasingly concerned about the need to overcome the deficiency of traditional sources of energy and about environment. Energy harvesting exploits unintentional vibrations from the environment via the piezoelectric effect to generate electrical energy. The electrocaloric effect, the change of temperature due to dipole ordering, will find applications in cooling technologies on different scales, from microelectronics, microrobotics, to house appliances.
Some of the project-group members from JSI together with colleagues from Faculty of Mechanical Engineering, University of Ljubljana are authors of European and US patent applications (please refer to the socio-economic achievement no.1), which was in 2016 sold to a Slovenian house-appliance company Gorenje. Together with our industrial partners we are participating in a Strategic development-innovation partnership in the frame of the Smart Specialization strategy of Slovenia.
The company KEKO-EQUIPMENT, who is co-funding this project, is interested in production of such ceramic elements with the multilayer technology. This year the piezoelectric community is facing another EU ROHS directive, which allows only 3-years-time to find suitable replacements for commercially most widely used lead-based piezoceramics. Electrocaloric cooling elements are not yet on the market, undoubtedly they represent a niche for the company. The time for development of lead-free piezoelectric and electrocaloric layer elements with improved properties is right!
Most important scientific results
Interim report,
final report
Most important socioeconomically and culturally relevant results
Interim report,
final report
