Investigation of Activation Process of Membrane Electrode Assembly Obtained By Various Formulation Conditions for High-Temperature Polymer Electrolyte Fuel Cell

Abstract

Recently, the polymer electrolyte membrane fuel cells (PEMFCs) have attracted the great attention as energy conversion devices for powertrain for the fuel cell electric vehicle and a residential combined heat and power system due to the zero-emission of harmful gas and high energy efficiency. To overcome of the drawbacks of perfluorosulfonic acid (PFSA) membrane and Pt poisoning by CO, the high-temperature PEMFC (HT-PEMFC) has been developing over decades, which has significant advantages as compared to low-temperature PEMFC (LT-PEMFC). For example, it has a much better fuel tolerance, enhanced the reaction kinetics and a simple water management [1,2]. However, the practical power density of membrane electrode assembly (MEA) for HT-PEMFC is much lower than that of LT-PEMFC because of the huge activation loss by acid poisoning [3–5]. Thus, a large amount of Pt is required in the electrode to ensure the sufficient power and long-term durability, which is a critical issue for HT-PEMFC. Therefore, one of the most critical issue for the HT-PEMFC is the decreasing the Pt amount in the electrode without sacrificing the MEA performance [5]. In addition, the fabrication of electrode using the advanced supported catalyst is the very important topic for revealing the improved catalytic activity into performance of MEA [2,5]. In this study, various formulation parameters for making the catalyst slurry using ball-milling were investigated to obtain the smooth electrode for MEA. The parameters are the presence of a viscosity agent, the solid content, and the amount of binder for the MEA of HT-PEMFC. When the viscosity agent is added in the 2.5 wt.% in the catalyst slurry, the slurry is very suitable for making a coated electrode on the gas diffusion layer (GDL). On the contrary, while when the amount of viscosity agent is increased over than 5 wt.%, the electrode is not completely dried. The optimum solid content of catalyst in the slurry was determined in the range of 12 wt.% because if the amount of catalyst exceeded the 14wt.%, the electrode is peeled off severely after drying. The open circuit voltage and performance of MEA under HT-PEMFC condition is depended significantly on the amount of polyvinylidene fluoride (PVDF) in the catalyst slurry. The voltage at a very small current density at 0.008A/cm2 of MEAs with different amount of PVDF was decreased from 0.775 to 0.735 V by increasing the 10wt.% to 30 wt.% of PVDF, which provide the increase of the activation overpotential by poisoning of phosphoric acid on the Pt catalyst. However, the performance of MEA at 0.6A/cm2 was maximized as 0.44 V at the 30wt.% of PVDF in the catalyst slurry, which suggests that the Ohmic overpotential decreased with increasing the PVDF amount. In summary, for maximizing the MEA performance under HT-PEMFC at 150℃, the various conditions for the manufulation of electrode was invesitgated. The amount of PVDF has a significant effect on the performance of MEA. [1] J. Zhang, Y. Xiang, S. Lu, and S. P. Jiang, Adv. Sustainable Syst. 2, 1700184 (2018). [2] D. J. You, D. H. Kim, J. R. De Liled, C. Li, S. G Lee, J. M. Kim, and C. Pak, Appl. Catal. A: General 562, 250–257 (2018). [3] R. E. Rosli, A. B. Sulong, W. R. W. Daud, M. A. Zulkifley, T. Husaini, M. I. Rosli, E. H. Majlan, and M. A. Haque, Int. J. Hydrogen Energy 42, 9293–9314 (2017). [4] A. Chandan, M. Hattenberger, A. El-kharouf, S. Du, A. Dhir, V. Self, B. G. Pollet, A. Ingram, and W. Bujalski, J. Power Sources 231, 264–278 (2013). [5] S.-W. Choi, J. O. Park, C. Pak, K.H. Choi, J.-C. Lee, and H. Chang, Polymers 5, 77–111 (2013).