Comparative study of mixed- and alternating-layer C/Cr coated metal bipolar plates under high potentials toward proton exchange membrane fuel cells

To improve the durability of bipolar plates in proton exchange membrane fuel cells, two types of coatings with mixed- and alternating-layers (mix-C/Cr and alt-C/Cr) are comparatively evaluated. Both coating designing strategies meet DOE targets with i0.84 V declining to 0.10 and 0.27 mu A & sdot;cm- 2 and achieving low interfacial contact resistance of 1.14 and 1.01 m Omega & sdot;cm2 for mix-C/Cr and alt-C/Cr, respectively. Analysis suggests that alternating-layer prevent the delamination of C layer and contributes to multiple interfaces which polishing the interfacial potential distribution. The results of this study confirm the promise of mixed- and alternating-layer coating strategies for high-performance coatings on bipolar plates.