Carbon Tolerant Double Site Doped Perovskite Cathodes for High-Temperature Electrolysis Cells

Solid oxide electrolysis cells (SOECs) of configuration La0.85Sr0.15Cr0.2Co0.1Ti0.7O3-δ (LSCCT)//ScSZ//GDC-LSM have been fabricated and electrochemically tested for the electrolysis of CO2 and H2O. Performance of the cell has been compared with standard Ni-SDC/ScSZ/GDC-LSM cell. EIS results show that LSCCT//ScSZ//GDC-LSM cell has higher non-ohmic resistance than the standard cell in 5% H2-CO2 containing environment. However, Cu impregnation of the LSCCT cathode using wet impregnation technique results in significant reduction in the non-ohmic resistance. Decrease in the thickness of the LSCCT cathode also reduces both ohmic and non-ohmic resistances. With the applied electrolysis voltage of 1.6 V at an operating temperature of 800 °C, the cell exhibited stable performance in 5% H2O/CO2 for more than 50 h with the electrolysis current density of 0.45 A.cm-2. Post-tested LSCCT cathode showed no carbon deposition whereas standard cell showed filamentary carbon formation and pulverization. Observations pertaining to surface (gas – electrode) and interface (electrode – electrolyte) will be presented.