Investigation of metal foam porosity and wettability on fuel cell water management by Electrochemical Impedance Spectroscopy

Abstract

ABSTRACT Metal foam, as a potential alternative to conventional flow fields in proton-exchange membrane fuel cells (PEMFCs), has been adequately proven to possess high gas uniformity and water storage ability. In this study, various cathode flow fields including meatal foam and conventional parallel and serpentine flow fields are compared experimentally. Meanwhile, electrochemical impedance spectroscopy (EIS) is also used to characterize the impedances as a further evidence of water management capacity for different flow fields. The results indicate that the cell with metal foam can achieve up to over 80% power density than that of the serpentine flow field with one third pressure drop. The porosity selection of metal foam is dependent on the inlet relative humidity (RH) to reduce the polarization loss and maximize the cell performance. The inlet relative humidity is also an important factor to the PTFE loading strategy for effective water removal.