Periodic Reporting for period 1 - Portapower (Device for much improved performance portable power)
Reporting period: 2018-09-01 to 2020-02-29
Nevertheless, high operating temperatures (> 600° C) mean SOFCs have yet to find use in portable applications. Such high operating temperatures are needed to allow sufficient conductivity of ions across the electrolyte and fast reaction kinetics at the electrodes. Recent discoveries of Prof Driscoll’s group in relation to achieving higher ionic conduction in films as well as in creating mesoporous honeycomb, complex perovskite cathodes, with strong potential to push cathode operation temperature down, showed strong promise of lower operating temperature, high performance micro-SOFCs. Furthermore, her knowledge in growth of epitaxial oxides on buffered metal substrates gave the hope of more stable cells, compared to those on standard Si, which have stability problems.
The objectives of this project were therefore to exploit the above significant innovations to a) reduce the operating temperature of micro-SOFCs; b) demonstrate that these materials can be integrated into a full device in a commercially viable manner; c) develop such a micro-SOFC device in collaboration with industry.
Work to date saw the development of thin-film (~100 nm thick) cathode materials with state-of-the-art performance based on the widely studied (La0.60Sr0.40)0.95Co0.20Fe0.80O3 (LSCF) material system as well as manganite based cathodes. Specifically, we have shown that LSCF can be deposited as part of a nanocomposite thin film with MgO. By selectively removing the MgO to leave a mesooporous LSCF layer we have found that the cathode resistance can be substantially reduced, allowing for device operation at low temperatures (<400C). These results have been reported through a multitude of conference presentations and papers (noted below). Also, working with IREC (ERC CoG 2016 grant, ULTRA-SOFC) has led to strong cathode advances for Si-based micro-SFOCs.
The next phase of the project was to show that the high performance thin electrolyte + mesoporous cathodes could be fabricated on low-cost, commercially viable substrates such as stainless steel. This is non-trivial, as such nanocomposite thin films are typically only grown on expensive single-crystal substrates such as SrTiO3 to ensure high quality, epitaxial growth. To mitigate this, we sourced commercially produced stainless steel substrates with a highly oriented electrolyte thin-film coating (~ 1 micron thick YSZ). Next, we showed that cathode could be deposited in the same way upon these substrates. This marks a significant step in the progress towards the commercialisation of micro-SOFC’s.
Papers (published already or written and close to submission)
1. M. Acosta, F. Baiutti, A. Tarancón, and J. L. MacManus-Driscoll, “Nanostructured Materials and Interfaces for Advanced Ionic Electronic Conducting Oxides” Advanced Materials Interfaces 6 1900462 (2019).
2. B. Zhu, G Schusteritsch, P Lu, J.L. MacManus-Driscoll, CJ Pickard, Determining
Interface Structures in Vertically Aligned Nanocomposite Films. APL Materials 7 061105
(2019).
3. J. L. MacManus-Driscoll, M. P. Wells, C. Yun, J-W. Lee, C-B. Eom, and D. G. Schlom, “New approaches for achieving more perfect transition metal oxide thin films” APL Materials 8, 040904 (2020).
4. M. Wells, M. Acosta, F. Baiutti, and J. L. MacManus-Driscoll, “A route to high performance micro-solid oxide fuel cells on metallic substrates,” Manuscript in preparation.
5. F. Baiutti, F. Chiabrera, M. Acosta, D Diercks, J. Santiso, X. Wang, A. Cavallaro, A. Morata, A. Aguadero, H. Wang, J. L. MacManus-Driscoll, A. Tarancón, Strongly enhanced electrochemical performance and thermal stability of lanthanum manganite in highly ordered thin nanocomposite films”, Manuscript in preparation.
6. M. Acosta, F. Baiutti, X. Wang, A. Cavallaro, J. Wu, W. Li, S. C. Parker, A. Aguadero, H. Wang, A. Tarancón, J. L. MacManus-Driscoll, Ultrafast oxygen reduction kinetics in (La,Sr)(Co,Fe)O3 vertically aligned nanocomposites below 300 °C, Manuscript in preparation.
7. B. Zhu, G. Schusteritsch, C.J. Pickard, J.L. MacManus-Driscoll, Ionic conducting
STO/CeO2 interfaces, Manuscript in preparation.
8. M. Hope, B. Zhang, B, Zhu, D.M. Halat, P. Lu, J.L. MacManus-Driscoll, C.P. Grey, A new approach to probe interfaces in complex oxide heterostructures via solid state NMR, Manuscript in preparation.
Talks/ presentations
9. Around 7 internal talks and presentations were given on the work at CAM-IES (https://www.energy.cam.ac.uk/cam-ies) networking meetings and conferences held in the U.K by MacManus-Driscoll, Wells, Zhu, Acosta, Lovett, and Zhang.
10. M. Acosta, F. Baiutti, A. Tarancón, and J. L. MacManus-Driscoll, “Epitaxial Mesoporous Thin Films for Solid Oxide Fuel Cells Cathodes”, Networking Meeting of the Alexander von Humboldt Foundation, Buenos Aires, Argentina (2018).
11. M. Acosta, F. Baiutti, A. Tarancón, and J. L. MacManus-Driscoll, “Epitaxial Mesoporous Thin Films for Solid Oxide Fuel Cells Cathodes”, European Materials Research Society Conference, Strasbourg, France (2018).
12. M. Acosta, F. Baiutti, A. Tarancón, and J. L. MacManus-Driscoll, “Epitaxial Mesoporous Thin Films for Solid Oxide Fuel Cells Cathodes”, AIP Horizons Workshop Organised by J. Driscoll, International Conference Interfaces in Energy Materials, Cambridge, UK (4, 2018). https://horizons.aip.org/energymaterials/
13. M. Acosta, F. Baiutti, X. Wang, W. Li, H. Wang, A. Tarancón, and Judith L. MacManus-Driscoll “Epitaxial Mesoporous Thin Films for Solid Oxide Fuel Cells Cathodes”, Materials Science and Engineering, Darmstadt, Germany (2018).
14. M. Acosta and J. L. MacManus-Driscoll, “Epitaxial Mesoporous Thin Films for Solid Oxide Fuel Cells Cathodes”, Trinity College Forum, Cambridge, UK (2018).
15. M. Acosta, F. Baiutti, A. Tarancón, and J. L. MacManus-Driscoll, “Epitaxial Mesoporous Thin Films for Solid Oxide Fuel Cells Cathodes”, European Materials Research Society Conference, Strasbourg, France (2018).
16. F. Baiutti, M. Acosta, J. L. MacManus-Driscoll, and A. Tarancon, “Nanostructured ceramic electrodes for micro energy devices”, Joint IEEE International Symposium on the Applications of Ferroelectric, International Workshop on Acoustic Transduction Materials and Devices & Workshop on Piezoresponse Force Microscopy, Lausanne, Switzerland (2019).
17. J. L. MacManus-Driscoll, M. Wells, A. Lovett and B. Zhu “Power of Interfaces and Ionic Systems.” Invited talk, The Power of Interfaces: Fundamentals for Solid State Devices Meeting, The Royal Society, London (2020).
As described above, the project has seen the development of thin film cathode materials with state-of-the-art performance. More importantly, however, it has demonstrated that these materials can be easily grown on industrially relevant substrates to give devices with strong potential for long term stability over temperature cycling. The conventional Si substrates have serious problems in terms of film buckling and peel-off and this will be exacerbated for any device in service. Therefore, the impact of the work lies in the demonstration of a valid route to the commercialisation of micro-SOFCs for portable power applications. Owing to their high efficiency and low environmental cost, the widespread implementation of micro solid oxide fuel cells would have a profound impact on global society. In particular, industry sectors such as transport, aviation, and portable electronics stand to be revolutionised from the availability of low-cost, highly efficient, clean, and safe power sources.
The market for portable fuel cells remains in its infancy and has a forecasted compound annual growth rate of over 21% (MarketsandMarkets’ report “Fuel Cell Technology Market - Global Forecast To 2019”). Growth to date has been limited by the availability of viable technology solutions, and so the progress achieved through this project holds enormous potential to unlock this market. The potential of the work therefore encompasses both substantial environmental and economic impacts.
URL of the project’s public website https://driscoll.msm.cam.ac.uk/