Improved Water Management with Thermally Sprayed Coatings on Stainless Steel Bipolar Plates of PEMFC

We develop a thermally sprayed Ti coating for PEMFC stainless steel (ss) bipolar plates. It is subsequently modified with Au by electro-deposition. SEM reveals that the Au/Ti coating is 30.8 µm thick and rough. The presence of TiO2between Ti and Au is negligible, as confirmed by XRD and XPS. Potendiodynamic characteristics in O2-saturated 0.5 M H2SO4show that the Au/Ti/ss samples have comparable corrosion currents to Au/ss but higher corrosion potentials. The interfacial contact resistance (ICR) of Au/Ti/ss is 8.6 mΩ cm2 under a compaction pressure of 140 N cm-2. The performances of PEMFCs with Au and Au/Ti are similar at cell voltages higher than 0.75 V. However, at 0.6 V the Au/Ti coating diminishes the current and pressure instabilities of the PEMFC operating under strong flooding conditions. The effect also occurs in the oscillation frequency, confirming the unique property of Au/Ti for reducing the effect of flooding.