Electrodes / electrolyte interfaces optimization for the durability of Solid Oxide Electrolysis Cells – DJANGO

The DJANGO project is dedicated to High Temperature Steam Electrolysis (HTSE). This technology is really promising, with a high efficiency, but an important drawback delays its rise up. Indeed, the degradation rate of the electrochemical cells (2 or 3 %/1000h), for an objective of 1%/1000h, limits its development. This technology is therefore less competitive compared to others, like alkaline electrolysis. In this context, the Django project is focused on the improvement of the durability. It aims at conceiving, fabricating, and testing an electrochemical cell, composed with optimised electrodes composition and microstructure. A “non-optimised” cell (25cm²) in term of durability, fabricated by the CEA, partner of the project, is already available and shows high initial performances at the operating temperature target of 800 °C. It will be the basis for electrodes development leaded during the project. An innovative and promising oxygen electrode, Ln2NiO4+?, developed by the ICMCB, partner of the project, will also be evaluated. Each new electrode developed will be studied by SEM, TEM, XRD, impedance spectroscopy, and voltamperometry. A 3D reconstruction of the electrodes, coupled with a local model of the electrochemical mechanisms, will highlight the limiting process, concerning the initial performances and their degradation during operating time. These results will be a guide for the knowledge and the choice of the “ideal” microstructures and materials. Then, this “ideal cell” will be developed and tested to confirm the modeling results. Then, the upscaling (100 cm²) of the cell will be realised by the industrial partner, CTI. This will allow treating eventual difficulties of upscaling, in an early state of development, considering the future emergence of the high temperature electrolysis technology.