Recent Development of a High Performance Solid Oxide Electrolysis Cell at CEA

ABSTRACT

This article focuses on two distinct methods for manufacturing an innovative solid oxide electrolysis cell and enhancing its electrochemical performances. On the hydrogen side, the support porosity was increased and optimized to prevent gas diffusion limitations at high current densities. To quantify the porosity rate, two experimental techniques were compared: image analysis and mercury intrusion porosimetry (MIP). On the oxygen side, a new material and deposition technique were employed with the aim of obtaining nanostructured electrodes. All of these developments were integrated into a complete cell, and electrochemical performances (in both solid oxide electrolysis cells [SOEC] and SOFC modes) were compared with more conventional cells between 800°C and 700°C and for various gas flow rates (12, 18, and 24 NmL min ⁻¹  cm ⁻² ). Distribution of relaxation time (DRT) analysis from electrochemical impedance spectroscopy (EIS) data highlights the effect of porosity and the oxygen electrode on the electrochemical performances. Finally, the work on support porosity and the nanostructured oxygen electrode demonstrated the most significant improvement in current density at 1.3 V and 700°C, under high gas flow rates (24 NmL min ⁻²  cm ⁻² ). In this condition, the gain was 15.0% compared to the conventional cell.