EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Various alternative energy storage technologies are under development to balance the supply-demand mismatch of renewable energy sources, such as solar and wind sources, which are not stable and strongly related with different factors including weather changes or geographic location. Reversible Solid Oxide Cells (rSOC) are one of the most promising energy storage and conversion devices, which can be successfully scaled up for the decentralized energy storage and conversion applications. Reversible SOCs possess the capability of generating electrical energy and heat by utilizing chemical energy of fuel, and storage of surplus electrical energy in the fuel within the reversed operation mode. Effectively working air electrode with a high efficiency of oxygen reduction and oxygen evolution reactions is indispensable to ensure the high and stable performance of reversible SOCs. Moreover, fuel electrode-supported cell design allows to significantly reduce the cell’s ohmic resistance and maximize the electrochemical performance. The majority of developed air electrode materials for SOCs present either perovskite-type (ABO3-δ) or perovskite-related crystal structure, which is principally associated with a wide range of available chemical compositions, enabling to design and obtain desired structural, thermomechanical and mixed ionic-electronic transport properties.
In this work, GdBa0.5Sr0.5Co2-xCuxO5+δ double perovskites were evaluated as very promising air electrode materials for reversible fuel electrode-supported SOCs. Physicochemical properties regarding crystal structure, thermal expansion properties, oxygen content change vs temperature of the studied oxides, as well as the electrochemical performance were systematically investigated. In particular, very low cathodic polarization resistance of 0.041 Ω cm2 at 800 °C, stable over 100 hours, was recorded for the GdBa0.5Sr0.5CoCuO5+δ electrode in air. The results indicate that studied double perovskites can be considered as stable air electrode materials for fuel electrode-supported SOCs, allowing to obtain excellent electrochemical performance in the reversible operation.