A Ruddlesden-Popper oxide as a carbon dioxide tolerant cathode for solid oxide fuel cells that operate at intermediate temperatures

摘要

Solid oxide fuel cells(SOFCs) that operate at intermediate temperatures of 600 to 800℃ have recently received increased attention due to their improved durability, more rapid startup and shutdown, better sealing and lower cost than their counterparts operate at high temperatures. Nevertheless, intermediatetemperature SOFCs(IT-SOFCs) with popular perovskite cathodes contain alkaline-earth elements, which are prone to reaction with carbon dioxide(CO_(2)), even when the CO_(2) content is comparatively low. In this work, an alkaline-earth metal-free Ruddlesden-Popper oxide, Nd_(1.8)La_(0.2)Ni_(0.74)Cu_(0.21)Ga_(0.05)O_(4+δ)(NLNCG), is developed for IT-SOFC cathodes. The cell is based on an electrolyte with 8%(mol) Y_(2)O_(3)-stabilized Zr O_(2)(8YSZ). The NLNCG cathode exhibits an excellent CO_(2) tolerance, as proven by thermogravimetry analysis,in situ X-ray diffraction, I-V-P test, and electrochemical impedance spectroscopy(EIS), and stability measurements. The anode-supported single-cell Ni O-YSZ|YSZ|NLNCG outputs a peak power density of 0.522 W·cm^(-2) at 800℃. These findings suggest that NLNCG could be a highly suitable cathode material with CO_(2) tolerance for IT-SOFCs.