Study On Surface Modification Of Metal Bipolar Plate For Proton Exchange Membrane Fuel Cell

Proton Exchange Membrane Fuel Cell (PEMFC) is viewed as a most promising power sources for transportation and portable application as a result of high power density, fast start-up and low operation temperature. Bipolar plate is one of the most key and expensive components in PEMFC. In order to reduce the cost of bipolar plate and enhance the volume energy density and power density, metal material is selected to substitute for traditional machined-graphite as bipolar plate for PEMFC. Stainless steel is one kind of widely investigated bipolar plate materials. However, the insufficient corrosion resistance and higher interfacial contact resistance can still not meet the requirement for the commercialization for PEMFC, the performance of material need further enhance.In our work, the 304 stainless steel and the Cr-coated 304 stainless steel were investigated. To simulate an aggressive PEMFC environment, a 0.05 mol/L H₂SO₄ + 2 mg/L F solution at 70℃ was used as test solution, bubbled thoroughly either with hydrogen gas (for simulating the PEMFC anode environment) or pressured air (for simulating the PEMFC cathode environment). The electrochemical tests such as potentiodynamic and potentiostatic polarization in the simulation PEMFC environments are measured and the ICR between the carbon paper (diffusion layer) and the sample is evaluated. To reduce manufacturing cost, solid chromizing was used to pure iron 10# carbon steel and 45# carbon steel, the structure was observed with metallographic microscope, and electrochemical performance and contact resistance were measured.The result indicates that 304 stainless steel has good corrosion resistance in the simulated PEMFC environment, the contact resistance obvious increases after potentiostatic polarization; the corrosion resistance and surface conductivity of 304 stainless steel are improved in the simulated PEMFC environment, and compare with pure hydrogen in anode environment, Cr-coated 304 stainless steel has better corrosion resistance in pure air in cathode environment. After treatment of solid chromizing,...