Experimental study of the durability of two different coatings for aluminium-based bipolar plates used in PEM fuel cell stacks

Abstract

This work presents an experimental study of the performance of PEM fuel cell short stacks assembled with aluminum plates. The stacks are formed by five cells with a cascade-type flow-field geometry. To prevent metal surface corrosion, two different coatings have been studied: chemical nickel, and tungsten carbide. The two stacks have been tested for 100 hour of continuous work. The performance of the stacks has been evaluated by constant monitoring of the current and voltage produced. Scanning electron microscopy has also been used to verify the deposition of dissolved metal ions over the catalyst layer and at the polymeric membrane. It has been verified that for the present experimental conditions the plates covered with tungsten carbide appear to have nicely resisted the tests without degradation. SEM-EDX and ICP-OES analyses of the membranes from the chemical nickel stack reveals the presence of Ni, Mg and Al traces that have to come from the plates. On the contrary, SEM-EDX analysis of the MEA corresponding to the tungsten-carbide coated stack does not detect the presence of metals from the superficial coating or those corresponding to the base metal plate. © J. New Mat. Electrochem. Systems.