20W class high temperature polymer electrolyte fuel cell (PEFC) stack with novel fabrication of membrane electrode assembly (MEA)

Abstract

Acid-doped polybenzimidazole (PBI) membrane and polytetrafluoroethylene (PTFE) based electrodes are used for the membrane electrode assmbly (MEA) in high temperature polymer electrolyte fuel cells (HTPEFCs). To find optimum PTFE contents in catalyst layer, PTFE ratio in the electrodes are varied from 25 to 50 wt.%. To improve performance of the electrodes, PBI is added to catalyst layer. 20 W class HTPEFC stack is fabricated with the novel MEA. The MEA consists of 8 layers (1 phosphoric acid doped PBI membrane, 2 electrodes, 1 sub-gasket, 2 gas diffusion media, 2 gas sealing gaskets). The sub-gasket mitigates the destruction of a highly acid-doped PBI membrane and provides long-term durability to the fuel cell stack. The stack is operated for 1,200 h without noticeable cell degradation.