Abstract
This study examines the impact of Carbon Nanotube (CNT) catalysts on the thermal characteristics of Proton Exchange Membrane Fuel Cells (PEMFCs) for aerospace applications. Using ANSYS Fluent 2022R1, a three-dimensional PEMFC model was simulated under three scenarios: Nafion membrane with a platinum-carbon (Pt/C) catalyst, polybenzimidazole (PBI) membrane with a Pt/C catalyst, and acid-doped PBI membrane with a platinum-carbon nanotube (Pt/CNT) catalyst. Operating at 160°C and a voltage range of 0.9V to 0.2V, the thermal properties were analyzed. Results showed that the Nafion scenario had a significant voltage decline with increasing current density due to electrochemical and thermal limitations. The acid-doped PBI membrane exhibited enhanced performance with better electrochemical kinetics and reduced resistance. The acid-doped PBI membrane with Pt/CNT catalyst achieved a peak current density of 1.251 A/cm² at 0.2V and increased internal energy to over 100 kJ/kg, compared to 19.8 kJ/kg for Nafion and 46.3 kJ/kg for acid-doped PBI. This improvement was due to Pt/CNT's superior thermal conductivity and heat transfer properties. The Pt/CNT catalyst also enhanced PEMFC output by supporting better electrochemical reactions, proton conductivity, and energy conversion. Additionally, it modestly increased water concentration at the cathode outlet. These findings highlight the potential of the PBI membrane and Pt/CNT catalyst combination for advancing PEMFC technology in aerospace applications, addressing the challenges of elevated operating temperatures.