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

摘要

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 Ce_(0.8)Gd_(0.2)O_(2-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.