AUTOmated exploration of MATerials for PROton-conducting solid oxide CELLS – AUTOMAT-PROCELLS

Solid Oxide Fuel/Electrolysis Cells are electrochemical devices based on ceramics which operate at high temperature, typically 600-800 °C. This high temperature is needed to ensure fast diffusion and reaction rates i.e. to allow for high power efficiency. Unfortunately, coupled with extreme operating conditions, high working temperatures lead to fast degradation. Materials discovery efforts have thus targeted new electrolyte and electrode materials with improved ionic and/or electronic conductivity and electrochemical activity, able to operate at a lower temperature. Other strategies concerned the development of new types of solid oxide cells, based on new charge carriers. Among these, Proton Conducting Cells, which can operate at a temperature below 600°C, are particularly promising. With typical performances of 0.3 W/cm2 at 600 °C in 2013, they can now reach 1.3 W/cm2 at 600 °C as reported in 2018. This is an increase of more than 300% in five years, which represents a significant acceleration.

To achieve such a performance, materials have been designed with complex compositions having typically 4-5 different cations, whose relative ratios were determined empirically. Still, the exploration of new or optimized compositions remains limited by the highly time-consuming tasks to fully characterize such materials. Thus, in the highly competitive international context of cells development and fabrication, new approaches allowing a fast screening of many compositions might constitute an efficient strategy to fasten the development of high-performing cells.

The objective of AutoMat-ProCells project is precisely to combine advanced research tools for screening efficiently the intrinsic properties of oxide materials for proton-conducting oxide cells. It is based on a high-throughput experimental approach. More concretely, our project couples the development of combinatorial deposition for the preparation of materials library bu pulse laser deposition, their exhaustive structural/chemical characterization in a highly efficient way including synchrotron-based techniques, and the measurement of electrolyte/electrode properties through electrical, isotope exchange and nuclear probe measurements. From this, we will obtain unique information on structure, stability, hydration, conductivity, electrochemical activity, the kinetics of ionic species transfer and diffusion, this for an extensive range of compositions. Through AutoMat-ProCells, we will also pave the path toward a renewed strategy for a very efficient exploration of materials for SOCs.

From AUTOMAT-PROCELLS, we expect the following results:
- a validation of the High-Throughput approach for the study and discovery of materials for PCFCs/PCECs, including the characterization of hydration and transport properties, stability and structural-chemical features,
- the production of exhaustive information (hundreds of different compositions tested) on important phase diagrams for proton-conducting solid oxide cells : BaZr0.8Y/Yb0.2O3-d- BaCe0.8Y/Yb0.2O3-d- BaSn0.8Y/Yb0.2O3-d ; LSM-LSC-LSF, or doped BaCo0.4Fe0.4Zr0.2FeO3-d,
- the identification of original compositions with optimized exchange, transport and electrochemical properties for proton-conducting solid oxide cells,
- the creation of technical advances in the field of High-throughput Experiments for materials discovery like (i) the design and fabrication of a furnace for large samples particularly adapted to the characterization of materials library (ii) the development of a low-cost route for combinatorial deposition of oxide materials (see below) (iii) the adaptation of SIMS for the characterization of combinatorial films.
- to help for the emergence of a dynamic in the French materials science community (starting from the application on fuel cells) toward the use of automated and parallelized approaches in research.