One key component in the PEMFC which contributes significantly to cost and still needs to be improved to ensure cell lifetime is the BiPolar Plate (BPP). The BPP provides the structural integrity of the PEMFC stack and moreover serves three purposes:

1) separation of the fuel and oxidant gases,

2) distribution of reactant gases to the cells and

3) electron flow through the PEMFC stack.

Metallic alloys such as stainless steels would be ideal as bipolar plates because they are amenable to low-cost/high-volume manufacturing methods such as stamping, offer high thermal and electrical conductivities, have low gas permeability and excellent mechanical properties, and can be readily made in foil form (∼≤ 0.1 mm thick) to achieve high power densities. The primary limitations are high electrical contact resistance, low corrosion resistance and high costs. To improve the physical properties of such metallic plates, electrical conductive and corrosion protective coatings are applied.

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