Fabrication and Characterization of Oxygen-Carbon-Contained CrMnFeCoNi Coatings Electrodeposited in DMF-CH3CN Solution with and without Supporting Electrolyte LiClO4

Abstract

Oxygen-carbon-contained CrMnFeCoNi coatings were electrodeposited in an organic solvent of DMF-CH3CN (N,N-dimethylformamide-acetonitrile) containing chlorides of chromium, manganese, iron, cobalt, and nickel, with or without supporting electrolyte lithium perchlorate (LiClO4). The coatings’ composition, structure, hardness, and electrocatalytic properties were examined. The presence of lithium in coatings obtained with LiClO4 showed it unsuitable as a supporting electrolyte in this fabrication process. Without LiClO4, oxygen-carbon-contained CrMnFeCoNi coatings were obtained at constant potentials at −2.0, −2.5, and −3.0 V (vs. SSE) by enhancing the concentrations of the target metal ions in the solution. These coatings were mainly amorphous with nanocrystals, which were comprised of >50 atom% oxygen atoms, >7 atom% carbon atoms, and near equiatomic Cr, Mn, Fe, Co, and Ni, showing a high level of hardness and advanced electrocatalytic activity in the oxygen evolution reaction.