Effects of O2 and H2 on the corrosion of SS316L metallic bipolar plate materials in simulated anode and cathode environments of PEM fuel cells

Increasing attention is being paid to the use of metallic materials as a replacement for non-porous graphite in bipolar plates (BPs) for polymer exchange membrane (PEM) fuel cells. The main aim of the present study was to investigate how O2 and H2 affect the corrosion behavior of 316L stainless steel in simulated anode and cathode environments of a PEM fuel cell. Open circuit potential (OCP) measurements together with potentiodynamic and potentiostatic tests were performed to investigate the corrosion behavior of SS316L in the O2- and H2-containing environments. Optical microscopy and scanning electron microscopy (SEM) were used to characterize the morphology of the corroded surface and the corrosion products. Inductively coupled plasma optical emission spectrometer (ICP-OES) was used to determine the levels of metal ions in solution after corrosion. The OCP and potentiodynamic tests showed that less corrosion of SS316L took place in a simulated cathode environment because it was easier to passivate SS316L in an O2-containing environment. However, the potentiostatic tests showed that there is less corrosion in a simulated anode environment, because H+ ions are reduced, and the resulting negative current can provide partial cathodic protection to the SS316L.