Empowering electro-ceramics: engineering the grain boundary crystallography

Empowering electro-ceramics: engineering the grain boundary crystallography

T Marquardt¹ & D. Pearmain² , Gareth Jones², Christopher Green².

¹University of Oxford, Department of Materials, Parks road,  ²Lucideon, Stoke-on-Trent, Staffordshire, ST4 7LQ, UK

In this project, the student has the opportunity to spend time at Lucideon synthesising YSZ via different processing routes, including flash sintering (Fig. 1). YSZ is one of the most advanced high-performance electro ceramics to date. Its selective oxygen transport and high thermal stability enable its application in batteries, solid oxide fuel and electrolyser cells, and nanosized powders related to catalysis.

Grain boundaries in YSZ are responsible for either dampening or enhancing properties critical for these devices' outstanding performance. Nevertheless, the distribution and type of grain boundaries in differently processed YSZ are not well understood. In this project, the student will synthesise YSZ at Lucideon and measure its capacitance. The samples will mimic those produced by Grimley et al.¹. In their study, they showed that YSZ produced via flash sintering has a grain boundary capacitance that is one order of magnitude lower compared to conventional sintered YSZ. This indicates changes in the grain boundary structure. The student will employ electron backscatter diffraction (EBSD) and electrical impedance spectroscopy (EIS) to study the grain boundary population difference between such samples and link grain boundary structure² to property. The results will be evaluated under the joint guidance of all supervisors.

References: ¹Grimley et al. (2021) J ECerS. ²Marquardt et al. (2018) Physics and Chemistry of Minerals.