Lanthanum nickelate as an efficient oxygen electrode for solid oxide electrolysis cell

International audienceThe present study focuses on an alternative structured oxygen electrode for solid oxide electrolysis cell (SOEC). La2NiO4+δ nickelate, LNO, was selected with respect to its mixed electronic and ionic conductivity and its good chemical stability. Complete single cells were built using screen printing of LNO and LaNi0.6Fe0.4O3 (LNF) layers on a standard hydrogen electrode supported half cell consisting of a porous NiO-YSZ layer, a dense 8YSZ electrolyte layer and a thin interlayer of GDC. The LNO cells polarization curves under various anodic flows of H2O/H2 (90/10) show excellent performances compared to the commercial LSCF (La0.6Sr0.4Co0.2Fe0.8O3-x) based cells. The steam conversion ratio SC increases from around 40% to 80% when the gas flow decreases from 36 to 12 NmL min-1 cm-2. With a degradation rate of 1.5% 1,000 hrs-1 after 500 hrs operating time (i =-0.5 A cm-2) at 800 °C, using a medium H2O/H2 (90/10) gas flow of 24 NmL min-1 cm-2 , LNO oxygen electrode shows higher durability than the state of the art LSCF oxygen electrode. Energy efficiency analysis confirms the dependency of the total efficiency with the current density and gas flow allowing us to suggest optimized conditions for reaching targets of commercial H2 production