Investigating the effects of methanol-water vapor mixture on a PBI-based high temperature PEM fuel cell

Abstract

This paper investigates the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC). A H 3 PO 4 -doped polybenzimidazole (PBI) membrane electrode assembly (MEA), Celtec P2100 of 45 cm 2 of active surface area from BASF was employed. A long-term durability test of around 1250 h was performed, in which the concentrations of methanol-water vapor mixture in the anode feed gas were varied. The fuel cell showed a continuous performance decay in the presence of vapor mixtures of methanol and water of 5% and 8% by volume in anode feed. Impedance measurements followed by equivalent circuit fitting revealed that the effects were most significant for intermediate-high frequency resistances, implying that charge transfer losses were the most significant losses. Vapor mixture of 3% in feed, however, when introduced after operation at 8%, showed positive or no effect on the cell's performance in these tests. ▶ We study methanol-water mixture in a high temperature PEM fuel cell. ▶ EIS measurement were done to characterize the effects on durability. ▶ Methanol-water vapor mixtures of 5% and 8% degrade the fuel cell, while 3% improves its performance, if tested after 8%. ▶ The effects of methanol-water vapor mixture are partially reversible.