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Developing a corrosion resistant and electrically conductive coating on metallic bipolar plates is essential to mitigate the performance degradation induced by the high cathodic transient potentials(CTPs) in the start-up/shut-down(SU/SD) processes of polymer electrolyte membrane fuel cells(PEMFCs). Herein, a zirconium oxynitride(Zr2 N2 O) coating prepared by atomic layer deposition was used to improve the corrosion resistance of 304 stainless steel(SS) towards anodic dissolution at various CTPs. Results show that the Zr2 N2 O coating can provide effective protection at a CTP as positive as 1.1 V vs. Ag/AgCl. At all CTPs examined, the peak current density(ipeak) extracted from the pulse test of the coated specimen(Zr2 N2 O/SS) is two orders of magnitude lower than that of uncoated 304 SS, indicating that the presence of the Zr2 N2 O coating remarkably increases the corrosion resistance for the anodic dissolution induced by CTPs. More importantly, upon increasing the CTPs, 304 SS experiences severe intergranular corrosion after 4050 pulses, whereas Zr2 N2 O shows slight pitting corrosion. The quite low ipeak and the mitigated corrosion morphologies of Zr2 N2 O confirm that incorporating oxygen into the protective coating for achieving a high oxidation resistance is a feasible way to restrain the anodic dissolution caused by high CTPs. Analysis of the electron energy level diagrams of the passive film suggests a protective coating with a wider valence band contributed to the improved corrosion resistance towards the transpassive dissolution.