Review on Ammonia-Powered SOFCs: Fundamentals, Thermodynamics, Degradation Mechanisms, and Future Perspectives

Conventional technologies primarily powered by fossil fuels have led to significant environmental issues. Hydrogen, which is a carbon-free fuel, has emerged as a substantial energy sector in recent years. However, challenges related to its storage and long-distance transportation remain obstacles to its widespread use. Conversely, with its superior energy density (12.9 MJ L^–1) compared to hydrogen (5.6 MJ L^–1), ammonia is more amenable to transport and offers a CO₂-free alternative that is versatile enough for various power generation systems. In this context, solid oxide fuel cell (SOFC) technology stands out as an effective solution for directly converting ammonia into electrical energy with high efficiency. However, the progress of this technology is hampered by the sluggish kinetics of the chemical and electrochemical processes occurring at the anodes and catalysts, limiting its commercialization. This review covers the fundamental principles, thermodynamics, and kinetics of the ammonia dissociation reaction, offering a comprehensive overview of how these factors influence the electrochemical performance and long-term durability of direct ammonia fuel cells at both the single-cell and stack levels. Furthermore, it provides critical insights for improving performance and mechanistic understanding while establishing a conceptual framework for the design of electrodes for ammonia-powered SOFC.