Electrochemical performance of CO2 electrolysis in an electrolyte-supported (NiO-YSZ/NiO-SDC/ScSZ/LSCF-GDC/LSCF) solid oxide electrolysis cell

This study investigated the electrochemical performance of CO2 electrolysis in an electrolyte-supported (NiO-YSZ/NiO-SDC/ScSZ/LSCF-GDC/LSCF) SOEC button cell at different temperatures (700, 750, 800, and 850 °C), CO2 gas concentrations (10, 30, and 60%), and applied voltage under OCV and electrolysis conditions. From FE-SEM analysis of the pristine cell, porous fuel and air electrode layers adhere well with the dense electrolyte. A smooth transition from SOFC to SOEC mode occurs across the OCV, signifying the reversibility of the cell. Higher temperatures favor fast electrochemical reaction kinetics. Area-specific resistance (ASR) values are lower in the SOFC than in the SOEC. The ASR value decreases as the CO2 concentration decreases from 60 to 10%. High potential helps electrode activation and enhances the activity. At 1.5 V, the Rp values for 10 and 30%CO2 gas concentration are 8.09 Ω.cm2 and 34.71 Ω.cm2, respectively. The CO2 gas concentration significantly affects the Rp value. The gas diffusion resistance predominantly contributes to the total polarization resistance.