Boosting steam tolerance and electrochemical performance of an La0.6Sr0.4Co0.2Fe0.8O3−δ-based air electrode for protonic ceramic electrochemical cells

Abstract

La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF) is the state-of-the-art air electrode material for solid oxide electrochemical cells using oxide-ion electrolytes, yet its application in proton ceramic electrochemical cells (PCCs) remains limited, mainly attributed to its instability under operating conditions of high temperature and high humidity. To address this issue, coating a PrCoO_3−δ (PCO) catalyst onto the LSCF scaffold has been evaluated in this study. The introduction of the PCO coating not only enhances the LSCF electrode's electrochemical performance but also significantly improves its steam tolerance by preventing direct contact between steam and LSCF. A PCC single cell with the PCO-coated LSCF air electrode exhibited a peak power density of 1.14 W cm⁻² in fuel cell mode and a current density of 2.04 A cm⁻² at an applied voltage of 1.3 V in electrolysis cell mode at 650 °C. Furthermore, single cells demonstrated excellent durability under operating conditions of high temperature and high humidity, maintaining stable operation for over 1100 h at a current density of −0.5 A cm⁻² in humid air at 600 °C. This research highlights the potential of surface modification on LSCF as a promising air electrode for PCCs to achieve efficient and stable operations.