The Effects of Relative Humidity on the Performances of PEMFC MEAs with Various Nafion Ionomer Contents

Title
The Effects of Relative Humidity on the Performances of PEMFC MEAs with Various Nafion Ionomer Contents
Authors
김근호이관영이상엽조은애임태훈김형준윤성필김세훈임태원장종현
Keywords
PEMFC; MEA (membrane-electrode assembly); Relative Humidity; Nafion Ionomer; CCM (catalyst-coated membrane) spraying method
Issue Date
2009-04
Publisher
The 10th Asian Hydrogen Energy Conference (AHEC 2009)
Citation
, 331-342
Abstract
For PEMFC operation, water nlanagelnent is very impoiltant to pIovide both sufficient proton conductivity and mass tlansport. Therefbre, in this study. the efEbct of relative humidity(38~ 87%) on cell performances have been exalnined for PEMFC MEAs with variious Nafion ionomer content, which were fabricated by CCM (catalyst-coated membrane) splaying Illethod. As the relative humidity of cathodes (RHC) increases, the cell voltages at 0.4 and 1.2 A/cm2 increased for the Μ EA with 20 wt% ionomer. This can be explained by the exponsion of active sites with enhanced ionic conductivity(activation overpotential). In contrast, with higher RHC, the cell voltages for 35 wt% ionomer (more hydrophilic), gradually decreased as a result of slowed gas transport (concentration overpotential). The MEAs with intermediate ionomer contents, 25 and 30 wt%, the cell voltage at 0.4A/cm2 showed maximum value at RHC 67%, where the mass transport starts ιo be more dominant factor. The highest unit cell performance was observed for the MEA with ionomer content of 25wt% at RHC 59%, and 20wt% at higher humidity of 87%, respectively.
URI
http://pubs.kist.re.kr/handle/201004/35158
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