Doped DLC for bipolar plate (BPP)

Abstract

The present invention relates to a metallic bipolar plate comprising a metal substrate and at least one layer of a non-hydrogenated transition metal-doped diamond-like carbon (DLC) provided on the metal substrate, wherein the non-hydrogenated DLC comprises at least one transition metal selected from groups 4d, 5d and 6d of the periodic table of elements and a part of the at least one transition metal is present in the form of carbide of the at least one transition metal in the non-hydrogenated DLC as a matrix. The non-hydrogenated transition metal-doped DLC has an indentation hardness of ≥35 GPa, preferably of ≥40 GPa. The metal-doped DLC used as a coating of metallic bipolar plates in fuel cells and electrolyzers exhibits high corrosion resistance and low interface contact resistance even for longer lifetimes (>10,000 hours) and harsh operational conditions. Therefore, the present invention also pertains to such uses, and also to fuel cells, in particular proton exchange membrane fuel cells, and electrolyzers comprising such coated metallic bipolar plates. Further, the present invention provides a cathodic arc discharge deposition method for depositing a coating of non-hydrogenated DLC comprising at least one of the above-mentioned transition metals, which is preferably the non-hydrogenated transition metal-doped DLC.

Dependencies are inferred from the claim text.