Enhanced Oxygen Evolution Rate and Anti-interfacial Delamination Property of the SrCo0.9Ta0.1O3-δ@La0.6Sr0.4Co0.2Fe0.8O3-δ Oxygen-Electrode for Solid Oxide Electrolysis Cells

Interfacial delamination between the oxygen-electrode and electrolyte is a significant factor impacting the reliability of solid oxide electrolysis cells (SOECs) when operating at high voltages. The most effective method to mitigate this delamination is to decrease the interfacial oxygen partial pressure, which can be accomplished by amplifying the oxygen exsolution rate and the O^2- transport rate of the oxygen-electrode. In this study, a SrCo_0.9Ta_0.1O_3-δ (SCT) film with an outstanding oxygen surface exchange coefficient and an outstanding O^2- conductivity was introduced onto the La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) surface by infiltration. This composite oxygen-electrode exhibited a notably high electrochemical catalytic activity primarily due to the significantly improved O^2- transport and oxygen surface exchange rate. Single cells with a 15-LSCF oxygen-electrode achieved a peak power density of 1.33 W cm^-2 at 700 °C and a current density of 1.25 A cm^-2 at 1.3 V (60% H₂O-H₂) at 750 °C. Additionally, an electrolysis cell with a 15 wt % SCT-infiltrated LSCF oxygen-electrode demonstrated stable operation even at high current densities for over 330 h with no noticeable delamination. The remarkable durability of the 15-LSCF oxygen-electrode can be attributed to the boosted oxygen exsolution reaction (OER) activity and the suppression of Sr segregation due to SCT infiltration. The impressive OER activity and resistance to interfacial delamination make the 15-LSCF a promising candidate for a composite oxygen-electrode in SOECs.