Co-electrolysis of steam and CO2 in a solid oxide electrolysis cell with La0.75Sr0.25Cr0.5Mn0.5O3−δ –Cu ceramic composite electrode.

Cu impregnation has been performed to improve electronic conductivity of La 0.75 Sr 0.25 Cr 0.5 Mn 0.5 O 3−δ (LSCM) material in reducing atmosphere, and solid oxide electrolysis cells (SOECs) with the configuration of LSCF|LSGM|LSCM–Cu are prepared and evaluated for high temperature steam and carbon dioxide co-electrolysis. Electrochemical impedance spectra (EIS) and voltage–current curves are carried out to characterize the cell performances. Compared with LSCF|LSGM|LSCM cell without Cu impregnation for steam electrolysis under the same conditions, EIS results show that LSCF|LSGM|LSCM–Cu cell not only displays lower ohmic resistance and better electrochemical performances, but also their resistance increases with the percentage of the fed CO 2 under open circuit voltage, in which the polarization resistance dominates. With the applied electrolysis voltage of 1.65 V and the operating temperature of 750 °C, the maximum consumed current density increases from 1.31 A cm −2 without CO 2 to 1.82 A cm −2 with 37.5% CO 2 . Although there is an increase of 2.0% in the applied electrolysis voltage, the cell has exhibited an excellent durability test for more than 50 h with the electrolysis current density of 0.33 A cm −2 and the gas mixture of 50% AH–25% H 2 –25% CO 2 at 750 °C. [ABSTRACT FROM AUTHOR]