Tense Solid Oxide Cells - Boosting Clean Energy Conversion through Nanoscale Strain

Successful transition from a fossil fuel based economy to a net-zero-emissions one based on renewables critically depends on the ability to store renewable energy and release it on demand. Solid oxide cells (SOCs) are such a core technology that can reversibly store renewable electricity into fuels suitable for long-range transportation, aviation and large-scale energy storage. Most importantly, SOCs can be used to produce clean power from fuels such as hydrogen (fuel cell mode), or, when operated in reverse, to convert power into hydrogen, or even into other synthetic fuel precursors by utilizing carbon dioxide (electrolysis mode).

As SOCs become increasingly more used, they also need to operate more efficiently and be more cost-effective and scalable. Since SOCs are built based on materials that combine good electronic and ionic conductivity with catalytic activity, advances in SOC technology have largely been driven by the quest to identify durable materials with increasingly higher conductivities. Typically this has been achieved by changing the crystal structure and chemistry of the materials. Alternative approaches based on physical, rather than chemical alterations are hugely promising, but require complex equipment to realize and are not particularly scalable. A key example is strain, or the 'tensing' of material's crystal structure which is introduced by depositing the material on a substrate with different crystal structure dimensions, thus artificially expanding or contracting the unit cell. Strain can be a remarkably powerful tool to tune materials and boost their performance: ~2% of expansive strain creates additional free space for ions to diffuse, boosting ionic conductivity by 2-3 fold, which is equivalent to 20% mol doping4, compressive strain brings atoms together, increasing orbital overlap and creating 'highways' for electron transport, thus increasing electronic conductivity and finally lowers useful conduction temperatures preventing degradation. In spite of these advantages, the application of strain and materials 'tensing' is limited to the production method described above and thus to thin films, which are two-dimensional systems (2D). For many applications and devices, three-dimensional (3D) structures are routinely required.

This PhD investigates a new approach to unlock strain within materials, in 3D, by nucleating 'a cloud' of nanoparticles within them, at nanoscale proximity of each other, creating 3D-'tense' materials and energy conversion devices. The project will use state of the art facilities to measure electronic and ionic transport properties, prepare and characterize materials and test them for power generation from hydrogen (power production), hydrogen production from steam (energy storage), as well as carbon dioxide and steam co-electrolysis to syngas, a key synthetic fuel/chemicals precursor (power-to-chemicals) as well as benchmark against equivalent state-of-the-art systems.

In addition to undertaking cutting edge research, students are also registered for the Postgraduate Certificate in Researcher Development (PGCert), which is a supplementary qualification that develops a student's skills, networks and career prospects.