A-Site Deficiency Ba0.9La0.1Co0.7Fe0.2Nb0.1O3-δ Perovskite as Highly Active and Durable Oxygen Electrode for High-Temperature H2O Electrolysis

The solid oxide electrolysis cell (SOEC) as an efficient and environmentally friendly energy conversion device can electrolyze steam efficiently and convert electricity into chemical energy. However, the lack of an efficient and stable oxygen electrode hinders the practical application of steam electrolysis in SOECs. In this paper, A-site deficiencies were incorporated into a Ba0.9La0.1Co0.7Fe0.2Nb0.1O3-δ (BL95CFN) perovskite oxygen electrode. It has been confirmed that the introduction of an A-site deficiency effectively improves the concentration of oxygen vacancies, which promotes the surface exchange of oxygen and accelerates the oxygen reduction reaction. In addition, after introducing the deficiency, the polarization impedance (Rp) of the BL95CFN oxygen electrode decreased from 0.162 to 0.087 Ω cm2 at 800 °C. Furthermore, under a 50% H2O atmosphere at 800 °C, the current density of BL95CFN reached 1.860 A cm–2 when the voltage reached 1.75 V, much higher than that of BL100CFN (1.428 A cm–2). Moreover, the A-site deficient BL95CFN demonstrated excellent performance in both short- and long-term stability, making it a promising candidate for application as a solid oxide electrolysis cell (SOEC) oxygen electrode material.