Presentation Title

Graphene-Based Coatings on a Martensitic Stainless Steel for Proton Exchange Membrane Fuel Cells

Faculty Mentor

Dr. Vilupanur Ravi, Chemical and Materials Engineering, Cal Poly Pomona

Start Date

17-11-2018 1:30 PM

End Date

17-11-2018 1:45 PM

Location

C301

Session

Oral 3

Type of Presentation

Oral Talk

Subject Area

engineering_computer_science

Abstract

Proton exchange membrane fuel cells (PEMFCs) are clean and efficient power resources. They only emit water vapor, thereby offering a viable approach to reduce greenhouse gas emissions. Challenges remain in making these power sources cost competitive. A crucial component of these fuel cells - the graphite separator plates - offer excellent corrosion resistance but are expensive and prone to fracture. They are also difficult to shape into thin sheets. Since these graphite separator plates account for about 60% of the cost of the fuel cell, an economical alternative should significantly reduce costs. Metallic substrates offer such a possibility. However, potential candidates for this application must be both corrosion resistant and electrically conductive. In this study, the surface of a martensitic stainless steel, UNS S41000, was modified to achieve enhanced corrosion resistance while retaining high electrical conductivity, ductility and low cost of the substrates. A graphene-based coating was selected as a promising candidate for modifying the surface of selected stainless steels. As-received and surface modified test coupons were subjected to electrochemical tests using a three-electrode flat cell in a simulated PEMFC environment, i.e. 0.01 M sulfuric acid, at 70°C. Scanning electron microscopy and X-ray diffraction were used to characterize the surface of the test coupons. Current results indicate that the surface modified coupons offer higher corrosion resistance than the as-received coupons.

Keywords: graphene, reduced graphene oxide, graphene oxide, PEM, proton exchange membrane fuel cell, ferritic steels, SS410, UNS S41000, corrosion

Summary of research results to be presented

Corrosion tests performed on graphene oxide coated UNS S41000 steel indicate that the surface modified coupons offer higher corrosion resistance than the as-received coupons, along with a 5-fold reduction in corrosion current values. The average corrosion current density for the coated sample was 149.2 ± 52.0 μA/cm2, respectively. In comparison, the uncoated UNS S41000 substrate had a corrosion current density of 669.8 ± 178.2 μA/cm2. Additionally, the resistance to polarization, Rp, values approximately doubled for the surface modified samples in comparison to the as-received coupons.

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Nov 17th, 1:30 PM Nov 17th, 1:45 PM

Graphene-Based Coatings on a Martensitic Stainless Steel for Proton Exchange Membrane Fuel Cells

C301

Proton exchange membrane fuel cells (PEMFCs) are clean and efficient power resources. They only emit water vapor, thereby offering a viable approach to reduce greenhouse gas emissions. Challenges remain in making these power sources cost competitive. A crucial component of these fuel cells - the graphite separator plates - offer excellent corrosion resistance but are expensive and prone to fracture. They are also difficult to shape into thin sheets. Since these graphite separator plates account for about 60% of the cost of the fuel cell, an economical alternative should significantly reduce costs. Metallic substrates offer such a possibility. However, potential candidates for this application must be both corrosion resistant and electrically conductive. In this study, the surface of a martensitic stainless steel, UNS S41000, was modified to achieve enhanced corrosion resistance while retaining high electrical conductivity, ductility and low cost of the substrates. A graphene-based coating was selected as a promising candidate for modifying the surface of selected stainless steels. As-received and surface modified test coupons were subjected to electrochemical tests using a three-electrode flat cell in a simulated PEMFC environment, i.e. 0.01 M sulfuric acid, at 70°C. Scanning electron microscopy and X-ray diffraction were used to characterize the surface of the test coupons. Current results indicate that the surface modified coupons offer higher corrosion resistance than the as-received coupons.

Keywords: graphene, reduced graphene oxide, graphene oxide, PEM, proton exchange membrane fuel cell, ferritic steels, SS410, UNS S41000, corrosion