Durability of a niobium thin film for bipolar plates in PEMFC

The durability of a niobium (Nb) thin film deposited on AISI 316L by magnetron sputtering was investigated in simulated polymer electrolyte membrane fuel cell (PEMFC) environments. The result of a potentiostatic test in a simulated corrosion environment showed that the current densities of the cathode and anode were 1.56 × 10−7 and -7.2 × 10−7 A/cm2, respectively.Before and after the potentiostatic test, the value of the interfacial contact resistance (ICR) increased 40.1 mΩ cm2 at 1.5 MPa. The cell performance observed with the Nb-bipolar plate (BP) was slightly decreased compared to the commercial graphite-BP over this test period. After a 300 h durability test, cell performance of the Nb–BP unit cell was slightly decreased by 5.4% at a current density of 400 mA/cm2.

► The Nb films were deposited on AISI 316L by magnetron sputtering.
► The durability of an Nb film is investigated in simulated PEMFC environments.
► The cathode was affected more severely than the anode in the Nb film.