Preparation and performance of PANI/CNTs composite coating on 316 stainless steel bipolar plates by pulsed electrodeposition

Abstract

Compact polyaniline (PANI) coating and polyaniline/carbon nanotubes (PANI/CNTs) composite coating are prepared on the surface of 316 stainless steel bipolar plate for proton exchange membrane fuel cells by a new method of pulse electrodeposition. The micro morphology shows that the PANI coating prepared by pulse electrodeposition is more uniform and compact than that by direct current electrodeposition. The compactness, corrosion resistance and electrical conductivity of PANI coating are further increased after CNTs are compounded. The results show that compared with PANI coating, the corrosion potential of PANI/CNTs coating is increased by about 78 mV, and the corrosion current density is reduced by an order of magnitude. Under the working potential of 0.6 V (vs. SCE), the current density of PANI/CNTs coating is reduced to about 1.9 μA·cm−2. After potentiostatic test for 5 h, there was no obvious corrosion on the surface of the coating. The interfacial contact resistance (ICR) contact resistance of PANI/CNTs coating is reduced by 35 % compared with PANI coating, and after the polarization process, PANI/CNTs coating has lower contact resistance than PANI coatings. The improved corrosion resistance and electrical conductivity of PANI/CNTs coating can be better applied in the protection of bipolar plates.