Water Management in PEMFCs Using Absorbent Wicks

Abstract

A water management strategy for polymer electrolyte membrane fuel cells (PEMFCs) using different kinds of absorbent wicks was investigated. Through this technology, water produced by the electrochemical reaction is transported to the inlet region of the reactant gas and used to humidify the dry reactant gas on the cathode side. For the thin membrane (Nafion 112) used, the back-diffusion of water from the cathode to the anode is sufficient to humidify dry hydrogen and to prevent drying out of the anode in the counterflow mode. Due to an improved water distribution in the whole region of the cell, PEMFC with superabsorbent wicks can be operated without external humidification of the reactant gases and still outperform the common one without wicks operated with dry or humidified gases. The performance of the cell with superabsorbent sponge was stable under high-current-density conditions (I=1.2(I=1.2 A/cm²), and little performance degradation was observed over a 120 h investigation period when both dry hydrogen and dry air were fed. © 2004 The Electrochemical Society. All rights reserved.