Improved mesostructured oxygen electrodes for highly performing solid oxide cells for co-electrolysis of steam and carbon dioxide

Mesoporous ceria possesses high potential as a functional material for high-temperature energy applications, owing to an ordered percolation network for oxygen ion conductivity, a good catalytic activity towards solid/gas reactions and a maximized porosity in the nanometric range. Here we developed highly performing gadolinium-doped mesoporous cerium oxide scaffolds for solid oxide cell oxygen electrodes by introducing chemical post-treatments into the state-of-the-art hard-template nanocasting synthesis route. The so-obtained improved mesoporous backbones were infiltrated with a mixed ionic electronic conductor (strontium- and iron-doped lanthanum cobaltite) forming a nanocomposite with excellent compatibility with the electrolyte. The resulting full solid oxide cells exhibit remarkable functional properties yielding an excellent performance in fuel cell and co-electrolysis of steam and carbon dioxide modes with a maximum power density of 1.35 W cm-2 at 0.7 V and an injected current of 1.30 A cm-2 at 1.3 V, respectively, at T = 750 °C. These values surpass those of the state-of-the-art benchmark cells, sparking the interest towards novel strategies based on ceramic nanocomposites for a new generation of solid oxide cells.