Deterioration Phenomena of a High Temperature PEM Fuel Cell with Bare SS304 Bipolar Plates

The high temperature proton exchange membrane (HT-PEM) fuel cell using metal bipolar plates (BPs) can solve some challenges of traditional PEM fuel cells, including low CO tolerance and high BP cost. To improve its operating life, understanding the deterioration phenomena of the HT-PEM fuel cells using bare metal BPs is necessary. This work studies this fundamental subject and verifies the reasons for the cell deterioration. The experimental results indicate that the cell power with bare SS304 BPs decreases by about 53.5%, and the total cell resistance increases by about 92.5% after a continuous 384-h operation. The increase in the electrical resistance of the BPs due to formation of a passivation film on the SS304 surface is the major reason for the deterioration phenomena. Moreover, the cathodic BP after a continuous operation has a larger rugged surface area and a wider O and P elements distribution than the anodic BP, because of more produced water and more phosphoric acid leaks on the cathode side during operation, which causes more serious oxidation and corrosion problems. A stricter anti-corrosion criterion for the cathodic metal BP may be needed for this type of fuel cell.