Symmetrical La³⁺-doped Sr₂Fe_1.5Ni_0.1Mo_0.4O_6-δ Electrode Solid Oxide Fuel Cells for Pure CO₂ Electrolysis

Electrochemical reduction of the greenhouse gas CO 2 in solid oxide electrolysis cells (SOECs) has attracted much attention due to their high energy conversion efficiency and great potential for carbon cycling. Compared with the asymmetrical configuration, symmetrical SOECs with the same material as anode and cathode, can greatly simplify the fabrication process and reduce the complication associated with varied interfaces. Perovskite oxides La x Sr 2-x Fe 1.5 Ni 0.1 Mo 0.4 O 6- (L x SFNM, x=0.1, 0.2, 0.3 and 0.4) are prepared and evaluated as symmetrical electrodes in solid oxide electrolysis cells for electrochemical reduction of pure CO 2 . The polarization resistances are 0.07 cm 2 in air and 0.62 cm 2 in 50% CO-50% CO 2 for L 0.3 SFNM electrode at 800 . An electrolysis current density of 1.17 Acm -2 under 800 at 1.5 V is achieved for the symmetrical SOECs in pure CO 2 . Furthermore, the symmetrical cell demonstrates excellent stability during the preliminary 50 h CO 2 electrolysis measurements.