Investigation of Corrosion Effects of Carbon Based Bipolar Plate Material for HT-PEMFCs

Abstract

In this study, a carbon/polyphenylene sulfide composite bipolar plate (BPP) is investigated electrochemically to determine its stability and suitability in high temperature (HT) proton exchange membrane fuel cell (PEMFC) application. BPP samples are subjected to chemical treatment at both low phosphoric acid (PA) concentration (0.5 M) at 80 ºC, and high phosphoric acid concentration (85 wt.% PA; ~14.6 M) at 160 ºC for specific duration. Chemically aged BPP samples have been electrochemically characterised by using a three-electrode cell device. For this measurement, low concentrated PA solution as well as high concentrated PA have been used as electrolyte. The device temperature has been varied with respect to PA concentration during the electrochemical characterisation. Three different potentiostatic polarisation conditions are employed such as open circuit potential (OCV), low potentiostatic polarisation (+0.1 VRHE), and high potentiostatic polarisation (0.8 VRHE). To assess the oxidation resistance behavior of the BPPs, cyclic voltammetry (CV) was recorded after the above mentioned potentiostatic polarisation measurements. In addition, the results of ante- and post-mortem examinations of BPPs were reported by using a microcomputed X-ray tomography system (μ-CT).