Enhanced electrochemical activity and durability of a direct ammonia protonic ceramic fuel cell enabled by an internal catalyst layer

Abstract

Ammonia is a promising fuel for protonic ceramic fuel cells (PCFCs), because of the high content of hydrogen and the advantages of safety and carbon neutrality. However, the wide application of PCFCs on ammonia fuel is greatly hindered by the relatively low electrochemical activity and durability. Here, we report a high-performance ammonia-fueled PCFC with enhanced electrochemical activity and durability, achieved by depositing an internal catalyst layer of an iron-doped ceria oxide (Fe-CeOx). It is demonstrated that the internal layer with a Fe: Ce molar ratio of 6:4 provides the best power output and durability. For example, when applied on tubular single cells with a configuration of Ni-BZCYYb (Fe-CeOx) || BZCYYb || PBSCF, a typical peak power density of 1.06 W cm−2 can be achieved on ammonia at 700 °C. The improved performance and longer lifetime are attributed to the Fe-CeOx internal catalyst, which can not only prevent the agglomeration of the particles during operation but also protect the Fe from reacting with ammonia to form iron nitride.