Passivation Behavior and Surface Resistance of Electrodeposited Nickel-Carbon Composites

Abstract

Bipolar plates in fuel cells and redox flow batteries are one of the most expensive components, which become a crucial factor for their commercialization. In this report, nickel and carbon are co-electrodeposited from Watts solution containing carbon black powder, and the Ni-C composites are characterized by SEM, EDS, XRD and surface profilometry. The intrinsic passivation behavior and the sheet resistance of Ni-C are on a par with pure Ni when carbon is introduced less than 26 at% in the composite, but the introduction of carbon to Ni suppresses the increase in sheet resistance after a storage corrosion test, which invites the expectation of high durability as bipolar plate materials. This kind of approach where carbon is introduced to metal-based bipolar plates by electrodeposition can improve the surface properties of pure metal bipolar plates with maintaining their price competitiveness over graphite-based composites and other high cost manufacturing techniques. (C) The Electrochemical Society of Japan, All rights reserved.