Challenges and Advancements in the Electrochemical Utilization of Ammonia Using Solid Oxide Fuel Cells.

ABSTRACT

Solid oxide fuel cells utilized with NH3 (NH3-SOFCs) have great potential to be environmentally friendly devices with high efficiency and energy density. The advancement of this technology is hindered by the sluggish kinetics of chemical or electrochemical processes occurring on anodes/catalysts. Extensive efforts have been devoted to developing efficient and durable anode/catalysts in recent decades. Although modifications to the structure, composition, and morphology of anodes or catalysts are effective, the mechanistic understandings of performance improvements or degradations remain incompletely understood. This review informatively commences by summarizing existing reports on the progress of NH3-SOFCs. It subsequently outlines the influence of factors on the performance of NH3-SOFCs. The degradation mechanisms of the cells/systems are also reviewed. Lastly, the persistent challenges in designing highly efficient electrodes/catalysts for low-temperature NH3-SOFCs, and future perspectives derived from SOFCs are discussed. Notably, durability, thermal cycling stability, and power density are identified as crucial indicators for enhancing low-temperature (550 °C or below) NH3-SOFCs. This review aims to offer an updated overview of how catalysts/electrodes affect electrochemical activity and durability, offering critical insights for improving performance and mechanistic understanding, as well as establishing the scientific foundation for the design of electrodes for NH3-SOFCs.