PNNL

Abstract

High-temperature solid oxide electrolysis cells (SOEC) are the most efficient devices for hydrogen production. Their long-term performance and durability are impacted by the Sr surface segregation in state-of-the-art Sr-containing oxides, lanthanum strontium cobalt iron oxide (LSCF) and lanthanum strontium cobalt oxide (LSC), due to Sr reactivity with the air gas impurities, such as chromium (Cr) and sulfur (S). Sr free oxygen electrodes would alleviate these issues to improve long-term device operation. In this work, we investigated the performance and stability of copper-doped La2NiO4 compositions with the Ruddlesden-Popper structure for oxygen evolution reaction (OER) using small and large area planar electrode-supported SOECs. Cells with the La2Ni0.8Cu0.2O4 (LNCuO-20) demonstrated a current density of up to 1.2 A/cm2 at 750°C at 1.3 V when operated in 90% steam in hydrogen versus air for over 1,000 hours. Materials scalability and applicability for practical devices were validated using 13 cm2 active area cells.