Improved performance and stability of Ag-infiltrated nanocomposite La0.6Sr0.4Co0.2Fe0.8O3−δ-(Y2O3)0.08(ZrO2)0.92 oxygen electrode for H2O/CO2 co-electrolysis

An Ag-infiltrated nanocomposite LSCF (La0.6Sr0.4Co0.2Fe0.8O3−δ)-YSZ (yttria stabilized zirconia) oxygen electrode is prepared for co-electrolysis of steam and CO2. Scanning electron microscopy (SEM) associated with energy dispersive X-ray spectroscopy (EDS) is employed to verify that nano-Ag particles are formed into the porous LSCF-YSZ electrode. Polarization curves and electrochemical impedance spectra (EIS) of the cell as well as long-term durability are investigated. In comparison with the Ag-free cell, the Ag-loaded cell exhibited improved performance and long-term stability when 45% H2O, 45% CO2, and 10% H2 is introduced as inlet gas. With infiltration of metal Ag, the ohmic resistance of the cell decreases from 0.14 Ω cm2 to 0.11 Ω cm2, and the polarization resistance from 0.30 Ω cm2 to 0.17 Ω cm2 at 800 °C. No significant deterioration of the Ag-infiltrated cell is observed when operating for 200 h at 1.3 V and 750 °C. With respect to varied H2O/CO2 ratio (1:2, 1:1, and 2:1) in feed gas, higher H2O percent content is resulted into higher cell performance, despite the fact that varied inlet gas composition did not dramatically influence the cell performance.