Enhanced La0.6Sr0.4Co0.2Fe0.8O3–δ-based cathode performance by modification of BaZr0.1Ce0.7Y0.1Yb0.1O3–δ electrolyte surface in protonic ceramic fuel cells

Abstract Effect of the cathode/electrolyte interface modification by applying a porous BaZr0.1Ce0.7Y0.1Yb0.1O3–δ (BZCYYb) interlayer (PBI) on cathode performance in protonic ceramic fuel cells (PCFCs) is investigated to achieve a lower temperature operation with high power density. Here, in a PCFC with anode-supported configuration, a proton-conducting oxide of BZCYYb is used as the material for both the interlayer and electrolyte, and demonstrates that this interlayer improves the cathode/electrolyte interfacial structure by increasing the electrochemically active triple-phase boundary (TPB). This BZCYYb interlayer has a porous structure formed on the dense BZCYYb electrolyte. A cathode material that is a composite of La0.6Sr0.4Co0.2Fe0.8O3–δ (LSCF) and BZCYYb fine particulates is impregnated into the submicrometer to single-micrometer pores within the PBI, yielding a three-dimensionally extended TPB region. This structure effectively enhances the cathode performance, and the resulting maximum power density of an anode-supported PCFC with a PBI reaches 1.05, 0.81, 0.57, 0.38, and 0.24 W cm−2 at 700, 650, 600, 550, and 550 °C, respectively. In conclusion, the modification of the cathode/electrolyte structure by applying a PBI is a simple, yet very effective approach to improve PCFC performance even when the cathode is a conventional material such as LSCF.