Low-Temperature, Anode-Supported High Power Density Solid Oxide Fuel Cells With Nanostructured Electrodes

Virkar, Anil V.

University of Utah

关键词: Cathodes;    Electrodes;    Power Density;    30 Direct Energy Conversion;    Electrolytes;   

DOI  :  10.2172/833840
RP-ID  :  NONE
RP-ID  :  AC26-99FT40713
RP-ID  :  833840

美国|英语

来源: UNT Digital Library

【 摘 要 】

Anode-supported cells comprising Ni + yttria-stabilized zirconia (YSZ) anode, thin ({approx}10 {micro}m) YSZ electrolyte, and composite cathodes containing a mixture of La{sub 0.8}Sr{sub 0.2}MnO{sub (3-{delta})} (LSM) and La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub (3-{lambda})} (LSGM) were fabricated. The relative proportions of LSGM and LSM were varied between 30 wt.% LSGM + 70 wt.% LSM and 70 wt.% LSGM + 30 wt.% LSM, while the firing temperature was varied between 1000 and 1200 C. The cathode interlayer composition had a profound effect on cathode performance at 800 C with overpotentials ranging between 60 and 425 mV at 1.0 A/cm{sup 2} and exhibiting a minimum for 50 wt.% LSGM + 50 wt.% LSM. The cathodic overpotential decreased with increasing firing temperature of the composite interlayer in the range 1000 {le} T {le} 1150 C, and then increased dramatically for the interlayer fired at 1200 C. The cell with the optimized cathode interlayer of 50 wt.% LSM + 50 wt.% LSGM fired at 1150 C exhibited an area specific cell resistance of 0.18 {Omega}cm{sup 2} and a maximum power density of 1.4 W/cm{sup 2} at 800 C. Chemical analysis revealed that LSGM reacts with YSZ above 1000 C to form the pyrochlore phase, La{sub 2}Zr{sub 2}O{sub 7}. The formation of the pyrochlore phase at the interface between the LSGM/LSM composite cathode and the YSZ electrolyte limits the firing time and temperature of the cathode interlayer.