Enhanced Densification of SDC Barrier Layers

Hardy, John S. ; Templeton, Jared W. ; Lu, Zigui ; Stevenson, Jeffry W.

Pacific Northwest National Laboratory (U.S.)

关键词: Cathodes;    X-Ray Diffraction;    Binders;    30 Direct Energy Conversion;    Electrolytes;   

DOI  :  10.2172/1035436
RP-ID  :  PNNL-20908
RP-ID  :  AC05-76RL01830
RP-ID  :  1035436

美国|英语

来源: UNT Digital Library

【 摘 要 】

This technical report explores the Enhanced Densification of SCD Barrier Layers A samaria-doped ceria (SDC) barrier layer separates the lanthanum strontium cobalt ferrite (LSCF) cathode from the yttria-stabilized zirconia (YSZ) electrolyte in a solid oxide fuel cell (SOFC) to prevent the formation of electrically resistive interfacial SrZrO{sub 3} layers that arise from the reaction of Sr from the LSCF with Zr from the YSZ. However, the sintering temperature of this SDC layer must be limited to {approx}1200 C to avoid extensive interdiffusion between SDC and YSZ to form a resistive CeO{sub 2}-ZrO{sub 2} solid solution. Therefore, the conventional SDC layer is often porous and therefore not as impervious to Sr-diffusion as would be desired. In the pursuit of improved SOFC performance, efforts have been directed toward increasing the density of the SDC barrier layer without increasing the sintering temperature. The density of the SDC barrier layer can be greatly increased through small amounts of Cu-doping of the SDC powder together with increased solids loading and use of an appropriate binder system in the screen print ink. However, the resulting performance of cells with these barrier layers did not exhibit the expected increase in accordance with that achieved with the prototypical PLD SDC layer. It was determined by XRD that increased sinterability of the SDC also results in increased interdiffusivity between the SDC and YSZ, resulting in formation of a highly resistive solid solution.