LAUSR

Abstract Reversible solid oxide cells (rSOCs) based on proton-conducting electrolytes represent an advanced electrochemical technology aimed at reversible energy conversion. Their high levels of efficiency, minimal impact on the environment and economic viability point to a positive future for rSOCs. In this study we present the results of electrochemical characterization of the Ca3Co4O9+δ-based oxygen (or steam) electrodes for rSOCs with the BaCe0.5Zr0.3Y0.2O3–δ electrolyte. The electrodes developed display excellent electrochemical activity both in the symmetrical and reversible cells. In detail, the electrode polarization resistance at 700 °C amounts to less than 0.25 Ω cm2 after long-term measurements (1500 h, symmetrical cell mode of operation) and lower than 0.13 Ω cm2 (open circuit voltage mode of operation), exceeding the electrode performances of other Co-based materials of “112” (LnBaCo2O5+δ, Ln is the lanthanide) and “114” (YBaCo4O7+δ) families. Analysis of these data shows that Ca3Co4O9+δ can be considered to be a promising alternative to the state-of-the-art electrodes utilized in protonic ceramic fuel and electrolysis cells.