Effect of interconnect coating procedure on solid oxide fuel cell performance

Abstract

Chromium (Cr) species vaporizing from chromia-forming alloy interconnects is known as a source of degradation in solid oxide fuel cell (SOFC) stacks called “cathode poisoning”. (Mn,Co)3O4 spinel coatings offer good protection against Cr evaporation during operation. In this study, Crofer 22 APU steel interconnects were electrophoretically deposited in different mediums to obtain high packing of green coating layer. The optimized sample was then sintered in air-atmosphere or dual-atmospheres (reducing-oxidizing). Anode-supported cells were exposed from cathode side to bare or coated interconnects for 100 h at 800 °C. The electrochemical performances of aged cells were compared at 800 °C. Due to higher density coating obtained by dual-atmospheres sintering process, the exposed cell showed performance similar to non-poisoned cell (0.95–0.98 W/cm2). The cell exposed to air-atmosphere sintered coating interconnect showed lower output power (0.75 W/cm2) due to coating lower density. The cell exposed to uncoated interconnect exhibited considerable degradation and the lowest power (0.66 W/cm2).