Effect of operating temperature on ammonia decomposition behavior and cell performance of direct ammonia solid oxide fuel cells

Direct ammonia solid oxide fuel cells (DA-SOFC) are regarded as a promising power generation technology. Nevertheless, the catalytic reaction of ammonia on the anode surface significantly affects DA-SOFC performance. This study explores the deterioration of DA-SOFC performance in the 550-700 degrees C and the interaction between NH3 decomposition and electrochemical reactions. The findings indicate that, at 550 degrees C, compared to H2, the reduction in power density of NH3 18.58% exceeds 4.56%t of NH3 d.s.g. (mixtures, 0.75H2 + 0.25N2). The anodic polarization impedance of NH3 exceeds that of H2 and NH3 d.s.g. by 51.1% and 28.9%, respectively. Cathode utilizing O2 has a dual impact on NH3 decomposition, at lower temperatures, oxidizing the anode's active site, decreasing NH3 decomposition rate, resulting in insufficient H2 supply, reducing electron transfer coefficient. Conversely, at higher temperatures, O2 promotes NH3 decomposition by boosting H2 consumption. However, more N2 is produced, increasing the concentration loss.