This work critically reviews recent developments in material characteristics and selection for the coating of bare metals used in the manufacture of bipolar plates (BPs) for PEM fuel cells. Several material types are considered in this work to provide the widest coverage of both established and emerging techniques. This includes discussion of defects observed in the coated material that emerged after the use of appropriate techniques to examine the coated surface after treatment. The work also provides a survey of the advances in the techniques used to coat the bare metal BPs. The work also considers the relative costs of the competing material and the methods used to apply them to the surface. The work discusses the results of the potentiostatic tests carried out on both the bare metal plates and the coated plates and for most cases it is possible to show that coated plates performed better than plates made of bare metals. This was confirmed by values obtained for properties such as interfacial contact resistance (ICR), corrosion resistance, corrosion current density (Icorr), and mechanical strength of the coatings. Also accelerated longevity studies confirmed the superiority of coated BPs. The work analyses the techniques used for coating and discusses their efficacy and the inherent drawbacks associated with the methods. It can be concluded that coating helps retards corrosion and improves the longevity of the fuel cell that enhances its cost competitiveness with other energy generation methods.
- Bipolar plate
- Corrosion resistance and corrosion current density
- Interfacial contact resistance
- Polarization curve
- Stainless steel