Boosted electrochemical performance of ca‐cobaltite‐based composite electrodes for reversible solid oxide cells.

Summary: In this article, the electrode performance of the misfit‐layered calcium cobaltite (C349), as cathode for solid oxide fuel and anode for solid oxide electrolysis cell (SOEC), is analysed by electrochemical impedance spectroscopy using a 3‐probe cell configuration. The addition of Ce0.8Gd0.2O2−δ (CGO20) as a composite electrode phase significantly boosts the electrochemical processes, decreasing the polarisation resistance (Rp) by approximately half an order of magnitude over the studied temperature range (550°C‐700°C). Electrical measurements under cathodic and anodic polarisation indicate that the C349/CGO20 composite is a promising oxygen electrode for reversible solid oxide cells with enhanced performance when operated as a SOEC anode. Short‐term stability testing of 50 h, under anodic polarisation at 700°C, demonstrates a stable current density with no observable microstructure delamination after measurements, being promising to avoid common degradation issues during SOEC operation. [ABSTRACT FROM AUTHOR]