Dr. Rebecca Clulow

Uppsala University, Sweden
Rebecca Clulow obtained her PhD in inorganic chemistry at the University of St Andrews (Scotland) in 2019 before taking up a position as a post-doctoral researcher at Uppsala University in Sweden (2020-2022). Since 2022 she has been establishing her own research group as an independent researcher and group leader at Uppsala University. Rebecca’s research is centred on high entropy materials with applications for proton conduction, hydrogen storage and magnetic properties. Her expertise encompasses structure-property relationships, diffraction and structural characterisation.

Talk title: High entropy proton conducting perovskites for solid oxide fuel cells

Materials with multiple principle elements have attracted significant interest in recent years particularly as high entropy alloys. Many of these materials are known to possess improved properties including hydrogen sorption and tensile strength as well as giving rise to interesting magnetic properties¹. In addition, the flexibility of possible compositions will lead to a high degree of tunability in the properties of these materials and allow for multiple functionalities. Whilst, this approach has already been extensively utilised in alloys, it has only more recently been applied to perovskites.²

One significant application for high entropy perovskites is as proton conducting materials in solid oxide fuel cells (SOFCs). SOFCs convert chemical energy directly to electrical energy with very high efficiencies and few emissions however, they are currently limited by their high operating temperatures.³ Proton -conducting solid oxide fuel cells (PC-SOFCs) provide a potential solution, though materials with the necessary properties still need to be developed. High entropy perovskites could overcome the current limitations of proton conducting materials allowing for the design of novel compounds with high ionic conductivity, stability and tunability.

In this talk, a new family of high entropy perovskites based on the n = 2 and n = 1 Ruddlesden-Poppers will be presented. Their general formulae are La_0.5Sr_2.5(M)₂O_7-_d (n = 2) and La_2-xSr_x(M)O_4-_d (n = 1) where M is a combination of four or more transition metals.^4,5 The compounds have been studied using a combination of neutron diffraction, X-ray diffraction, thermal analysis and magnetometry. The n = 2 compounds are oxygen deficient and exhibit unusual spin glass behaviour whilst the n = 1 materials absorb water from the air under ambient conditions which is a prerequisite for proton conduction.

References
1. D. B. Miracle and O. N. Senkov, Acta Mater., 2017, 122, 448–511.
2. S. Jiang, T. Hu, J. Gild, N. Zhou, J. Nie, M. Qin, T. Harrington, K. Vecchio and J. Luo, Scr. Mater., 2018, 142, 116–120.
3. S. Mekhilef, R. Saidur and A. Safari, Renew. Sustain. Energy Rev., 2012, 16, 981–989.
4. P. Pramanik, R. Clulow, D. C. Joshi, A. Stolpe, P. Berastegui, M. Sahlberg and R. Mathieu, Sci. Rep., 2024, 14, 3382.
5. R. Clulow, P. Pramanik, A. Stolpe, D. C. Joshi, R. Mathieu, P. F. Henry and M. Sahlberg, Inorg. Chem. Accepted