Performance of Carbonate - LaCoO3 and La0.8Sr0.2Co0.2Fe0.8O3-δ Composite Cathodes under Carbon Dioxide

• LaCoO3 (LC) and La0.8Sr0.2Co0.2Fe0.8O3-δ (LSCF) composite electrodes with NaLiCO3.
• LC and LSCF in composite electrodes for ceria-carbonate electrolytes.
• LSCF forms the most stable composite electrode, showing minor Sr loss in pure CO2.
• LSCF and LC-based composites are fully stable under 50% CO2 + 50% O2 mixtures.
• LC-based composite electrodes show the best electrochemical properties.

An investigation of the chemical compatibility and electrochemical performance of composite electrodes based on LaCoO3 (LC) and La0.8Sr0.2Co0.2Fe0.8O3-δ (LSCF) for ceria/carbonate composite electrolytes is presented. The tests are based on symmetric cells (electrode/electrolyte/electrode) prepared using Li2CO3 and Na2CO3 mixed with LC or LSCF as composite electrodes, and Gd-doped ceria mixed with the same carbonates as composite electrolyte. Reactivity tests performed at 550 °C for 5 h identified LSCF as the most stable perovskite in pure CO2, with only minor loss of Sr, while LC shows partial decomposition. The chemical stability of both materials exposed to lower CO2 activity is confirmed by X-ray diffraction. Cell assemblies tested by impedance spectroscopy in the temperature range 520-600 °C, in air and pure CO2, confirm the potential of these composite electrodes for intermediate temperature applications such as fuel cells and carbon dioxide permeation membranes.