Periodic Reporting for period 1 - TEOsINTE (Thermoelectric oxide composites: design through controlled interactions.)
Okres sprawozdawczy: 2020-10-01 do 2022-09-30
The main problem/issue addressed by this project is related with renewable energy and waste heat. This project intends to make use of the large number and variety of currently available, high-temperature (>400º C) waste heat sources as fuel, to generate electrical power from a temperature gradient directly, in solid state form, via the Seebeck effect. The functional materials capable of such a simple and useful technological feat are some state-of-the-art thermoelectric (TE) oxides (e.g. Ca3Co4O9, SrTiO3, CaMnO3 and ZnO), which present attractive high-temperature TE properties and are composed of cheap, abundant and environmentally friendly constituents. Their biggest problem is their relatively low conversion efficiencies (< 10 %) and little knowledge on the fabrication of reliable TE modules based on these materials, facts which still impede their use as industrial TE harvesters of waste heat. Their importance for society thus becomes obvious, presenting a promising future for the ecological, financial and energetic sectors. The main objectives of TEOsINTE are to research and develop (R&D) novel ceramic composites with enhanced high-temperature TE performance, using material design principles involving controlled interactions between the composite components including a main matrix component (state-of-the-art oxide) and a simple, secondary dispersed phase (transition metals and some of their oxides). Particular attention was given to using and testing them in prototype TE modules (proof-of-concept), capable of working in conditions inspired by real scenarios. The intended approaches involve the addition of selected dispersers into the bulk TE oxide matrices and, based on different controlled-interaction-with-the-matrix strategies/schemes unique to each TE system, promote the formation of novel TE composite materials with improved nano/microstructural features, stability and high-temperature TE performance. Other objectives include the elevation of the experienced researcher (ER) to the level of expert in oxide-based TE materials, with all the other correlated elements which come with this accomplishment (independency, new/improved collaborations, training of students and young researchers, attraction of competitive funding, exploration of other functional materials) and his inclusion in a more sustainable career position.
Finally, TEOsINTE (https://cordis.europa.eu/project/id/101003375) undoubtedly established that all the proposed goals can be successfully achieved in relatively simple and inexpensive ways for the Ca3Co4O9, ZnO and SrTiO3 systems, with only one exception in the CaMnO3 ceramic oxide system, which turned out to be a more complicated case than it was originally thought. The established TE oxides have thus been brought closer to the use in industrial TE harvesters of high-temperature waste heat, showing once again the remarkable power of the multidisciplinary materials science and engineering R&D.
Finally, TEOsINTE (https://cordis.europa.eu/project/id/101003375) undoubtedly established that all the proposed goals can be successfully achieved in relatively simple and inexpensive ways for the Ca3Co4O9, ZnO and SrTiO3 systems, with only one exception in the CaMnO3 ceramic oxide system, which turned out to be a more complicated case than it was originally thought. The established TE oxides have thus been brought closer to the use in industrial TE harvesters of high-temperature waste heat, showing once again the remarkable power of the multidisciplinary materials science and engineering R&D.
The work performed from the beginning to the end of the project was divided into the following four tasks:
Task 1. Materials selection, processing and screening.
Task 2. Structural and microstructural design of novel TE composites.
Task 3. Detailed studies of charge and heat transport mechanisms.
Task 4. Proof-of-concept and demonstration.
Very promising results were obtained for the Ca3Co4O9, SrTiO3 and ZnO-based systems. In the case of the calcium cobaltites prepared via a novel 2-stage method, the density was dramatically increased (more than 80% of the theoretical density) and the overall electrical properties (power factor, PF) were considerably improved (225 microW/m/K^2 at 975 K). For the novel ZnO TE materials prepared via aluminothermy, the density achieved is among the highest ever reported for this system (96 % of the theoretical density), while the attractive highest ZT value of 0.14 at 1175 K was achieved. The best results among all studied materials were obtained for the SrTiO3 system, where the newly discovered composites presented the highest TE performance at the highest working temperature (around 1240 K), together with best TE stability in air, for different time intervals and temperature gradients.
Some of the best results have already been published in open-access journals, while particular results and achievements from TEOsINTE can be found in social media, at
https://www.facebook.com/LabSSIEC
https://www.facebook.com/demac.univ
https://www.linkedin.com/in/gabrielconstantinescuphd1984/
Task 1. Materials selection, processing and screening.
Task 2. Structural and microstructural design of novel TE composites.
Task 3. Detailed studies of charge and heat transport mechanisms.
Task 4. Proof-of-concept and demonstration.
Very promising results were obtained for the Ca3Co4O9, SrTiO3 and ZnO-based systems. In the case of the calcium cobaltites prepared via a novel 2-stage method, the density was dramatically increased (more than 80% of the theoretical density) and the overall electrical properties (power factor, PF) were considerably improved (225 microW/m/K^2 at 975 K). For the novel ZnO TE materials prepared via aluminothermy, the density achieved is among the highest ever reported for this system (96 % of the theoretical density), while the attractive highest ZT value of 0.14 at 1175 K was achieved. The best results among all studied materials were obtained for the SrTiO3 system, where the newly discovered composites presented the highest TE performance at the highest working temperature (around 1240 K), together with best TE stability in air, for different time intervals and temperature gradients.
Some of the best results have already been published in open-access journals, while particular results and achievements from TEOsINTE can be found in social media, at
https://www.facebook.com/LabSSIEC
https://www.facebook.com/demac.univ
https://www.linkedin.com/in/gabrielconstantinescuphd1984/
The progress beyond the state-of-the-art is unquestionable. TEOsINTE has improved the key properties from all the state-of-the-art TE oxides studied, through most of the envisaged methods and approaches.
Socio-economic impact
A breakthrough in the efficiency of TE materials can have a significant technological and socio-economic impact on the global energy systems scale. TE generators can “recycle” part of the huge amount of waste heat lost day by day to our environment. In addition, reversing the effect (Peltier effect), TE refrigerators can be used as a “green” alternative to present-day cooling systems. These both ways of using the TE effects can dramatically reduce costs and maintenance jobs in “green” energy production and related matters, in parallel with opening new academic and industrial R&D branches, finding new applications for TE materials, creating higher awareness among the general population about the huge benefits of TE energy production and creating new and diverse jobs.
Ecological impact
The potential worldwide installation of TE generators equipped with such materials in heat engines can “recycle” 10 to 15% of the heat lost every year to the environment. Even with such relatively low yields, the global benefits would be tremendous, considering the fact that this technology has no apparent negative impact of any sort to life and the environment. Furthermore, it is nowadays widely accepted that any contribution to the global warming problem, however small, is hugely welcomed and is given full consideration, especially in well-developed countries. Making this technology more efficient, cheaper and more affordable for an increasing number of countries and people, regardless of their development stage and financial level, can have the ideal effect of replacing the classical fossil fuel energy sources altogether and lead to a zero greenhouse gas emission global society.
Scientific impact
The new data, results and knowledge acquired during and after the proposed research can be directly available to the scientific community and various industries, for future R&D of new TE materials and technologies using these particular functional materials. The new type of high-performing/high-stability TE composites which were developed in TEOsINTE can have well-quantified properties of interest and straightforward industrial production routes, and could therefore be used directly and successfully by potential industrial partners in different activities, applications and R&D schemes.
Socio-economic impact
A breakthrough in the efficiency of TE materials can have a significant technological and socio-economic impact on the global energy systems scale. TE generators can “recycle” part of the huge amount of waste heat lost day by day to our environment. In addition, reversing the effect (Peltier effect), TE refrigerators can be used as a “green” alternative to present-day cooling systems. These both ways of using the TE effects can dramatically reduce costs and maintenance jobs in “green” energy production and related matters, in parallel with opening new academic and industrial R&D branches, finding new applications for TE materials, creating higher awareness among the general population about the huge benefits of TE energy production and creating new and diverse jobs.
Ecological impact
The potential worldwide installation of TE generators equipped with such materials in heat engines can “recycle” 10 to 15% of the heat lost every year to the environment. Even with such relatively low yields, the global benefits would be tremendous, considering the fact that this technology has no apparent negative impact of any sort to life and the environment. Furthermore, it is nowadays widely accepted that any contribution to the global warming problem, however small, is hugely welcomed and is given full consideration, especially in well-developed countries. Making this technology more efficient, cheaper and more affordable for an increasing number of countries and people, regardless of their development stage and financial level, can have the ideal effect of replacing the classical fossil fuel energy sources altogether and lead to a zero greenhouse gas emission global society.
Scientific impact
The new data, results and knowledge acquired during and after the proposed research can be directly available to the scientific community and various industries, for future R&D of new TE materials and technologies using these particular functional materials. The new type of high-performing/high-stability TE composites which were developed in TEOsINTE can have well-quantified properties of interest and straightforward industrial production routes, and could therefore be used directly and successfully by potential industrial partners in different activities, applications and R&D schemes.