MATERIALS OF IMPROVED CORROSION RESISTANCE AND OXIDE OHMIC CONDUCTIVITY FOR MOLTEN CARBONATE FUEL CELLS

THE OPERATING LIFE OF A MOLTEN CARBONATE FUEL CELL (MCFC) STACK IS SEVERELY LIMITED BY METAL AND ELECTROLYTE LOSS CAUSED BY CORROSION OF CATHODE-SIDE BIPOLAR PLATE CURRENT COLLECTOR MATERIALS. IN THIS PROJECT, CONDUCTIVE LOW COST STAINLESS STEELS COATED WITH LITHIUM FERRITE (LIFEO2) WILL BE DEVELOPED TO DECREASE CORROSION AND ELECTROLYTE CREEPAGE LOSS AND TO SPEED THE COMMERCIALIZATION OF MCFC TECHNOLOGY. THE LITHIUM FERRITE LAYER WILL BE PROVIDED BY PRE-OXIDATION OF SELECTED STAINLESS STEELS IN THE PRESENCE OF MOLTEN CARBONATE. TO INCREASE SURFACE FE CONCENTRATION AND ENSURE A COMPACT, CONTINUOUS LIFEO2 LAYER, A PLATED FE THIN LAYER MAY BE APPLIED BEFORE PRE- OXIDATION. A NICKEL OR COPPER THIN LAYER MAY ALSO BE APPLIED UNDERNEATH SUCH AN FE LAYER TO IMPROVE LIFEO2 CONDUCTIVITY THROUGH DOPING. THE COMPACT LIFEO2 SHOULD PREVENT CARBONATE ATTACK ON A CR2O3 LAYER. THAT PREVENTS SUBSTRATE CATION DIFFUSION AND REDUCES OVER-ALL CORROSION ATTACK. BECAUSE CR2O3 DISSOLUTION IN CARBONATE IS EXPECTED TO BE LESS WITH SUCH A COATING, A LOW ELECTROLYTE LOSS ALSO IS EXPECTED.