Journal of Power Sources, Vol.269, 509-519, 2014
LaNi0.6Co0 4O3-delta dip-coated on Fe-Cr mesh as a composite cathode contact material on intermediate solid oxide fuel cells
The feasibility of using Crofer22APU mesh dip coated with LaNi0.6Co0.4O3-delta (LNC) ceramic paste as a uniform contact layer on a Crofer22APU channeled interconnect was studied. The control of LNC dip coating thickness on Fe-Cr mesh was carried out by rheological measurements of the suspension. SEM cross-section of formed composite contact material showed good adherence between ceramic and metallic components. The measured area specific resistance (ASR) value at 800 degrees C was 0.46 0.01 m Omega cm(2), indicating low contact resistance itself. The long term stability of metallic/ceramic composite was also studied. The contact resistance, when composite contact material was adhered to channeled Crofer22APU interconnect, was 5.40 +/- 0.01 m Omega cm(2), which is a suitable value for the performance of IT-SOFC stack. The stability of the system after treating at 800 degrees C for 1000 h was characterized using X-ray Micro-Diffraction (XRMD), Scanning Electron Microscope equipped with an Energy Dispersive X-ray analyzer (SEM-EDX) and X-ray Photoelectron Spectroscopy (XPS) techniques. The oxidation rate of the alloy and Fe3O4 phase formation were enhanced on the channels of the interconnect. Thus, the formation of CrO3 (g) and CrO2(OH)(2) (g) species was accelerated on the composite surface under the channel. Through XRMD and XPS analysis the coexistence of two perovskite phases (initial LNC and Cr-perovskite) was observed. (C) 2014 Elsevier B.V. All rights reserved.
Keywords:IT-SOFC;Composite contact material;Channeled interconnect;Ohmic resistance losses;Electrical contact;LaNi0.6Co0.4O3-delta