MCO-Coated Interconnects: Stack Testing and Results

Abstract

Coating development at FuelCell Energy (FCE) is a continuous activity looking at optimizing chemistry, application process and features of the coating for longer life of the solid oxide fuel cell (SOFC) stack in high humidity environment. Cathode interconnects surfaces are protected with manganese cobalt oxide (MCO) coatings to minimize chrome evaporation and poisoning of the fuel cell.Protecting the surface of cathode interconnects becomes necessary to extend the SOFC life. Two different coatings have been studied at FCE. MCO was either deposited as a perovskite by dip coating or formed in situ during stack operation. A direct comparison of the two methods was studied after hundreds of hours in SOFC stack testing both in dry and humid air environment. The stacks were tested in normal conditions with dry air in cathode and also in air with additional humidity. A significant improvement in degradation rate and cell stability has been observed and achieved with those stacks.

Materials Development for SOFC Applications

“…Metallic interconnects can be produced by high volume production processes, as publicized by Delphi (7). Versa Power (8) and General Electric (9) have also stated that their stack development paths anticipate the development of metal interconnects that can meet long term stability targets of >40,000 hour operation.…”