High conductivity and anti-corrosive tantalum surface modified ferritic stainless steel bipolar plate for direct ethanol fuel cell

Abstract Stainless steel is one of the cheap raw materials for fuel cell bipolar plates. However, it lacks sufficient corrosion resistance and surface conductivity in direct ethanol fuel cell (DEFC) environments. In this study, a tantalum modified layer is prepared on 430 stainless steel substrates (named Ta-430) by magnetron sputtering. X-ray diffraction (XRD) and scanning electron microscope (SEM) observation show that a high conductive α-Ta layer (about 2 μm in thickness) with dense and uniform structure is formed on 430 SS substrate. Electrochemical tests including potentiodynamic and potentiostatic polarization indicate that the Ta-430 displays greatly improved corrosion resistance and stable passivating behaviour in simulated DEFC anode and cathode environments. In addition, after 4 h potentiostatic tests, the Ta-430 exhibits much lower ICRs than that for the bare substrate due to the high conductive of the Ta modified layer.