Thermal, electrical, and electrocatalytical properties of lanthanum-doped strontium titanate

An Examination of SOFC Anode Functional Layers Based on Ceria in YSZ

“…Both anodes and cathodes were then fabricated by impregnation of the active components into the porous layers. The porous-denseporous YSZ structure was produced by laminating three green tapes, using pore formers in the layers that were to be porous, and then firing the structure to 1823 K for 4 h. 15 The green tapes were prepared by mixing YSZ powder ͑Tosoh Corp., 8 16 For the present investigation, it is only important to recognize that the LSF-YSZ has a current-independent impedance of 0.1 to 0.15 ⍀ cm 2 at 973 K. 16 The thickness of the 65% porous YSZ used in making the functional layer of the anodes was either 12, 50, or 100 m, and the porosity was introduced through the addition of graphite ͑GE, Alfa Aeser, 325 mesh, conductivity grade͒ into the green tape. Ceria was added to this layer by impregnation of an aqueous solution of Ce͑NO 3 ͒ 3 ·6H 2 O, followed by calcination at 723 K. After addition of ceria, a catalytic metal was added by impregnation of either ͑NH 3 ͒ 4 Pd͑NO 3 ͒ 2 , Ni͑NO 3 ͒ 2 ·6H 2 O, or Cu͑NO 3 ͒ 2 ·6H 2 O, followed by calcination at 723 K in air.…”

A Ceramic-Anode Supported Low Temperature Solid Oxide Fuel Cell

“…4 To overcome these issues, nickel-free metal oxide anode materials have been investigated, such as La 0.75 Sr 0.25 Cr 0.5 Mn 0.5 O 3−δ (LSCM), 5 Sr 2 Mg 1−x Mn x MoO 6−δ (x = 0 to 1), 6 and doped (La, Sr)(Ti)O 3 . 7,8 Experimental results have demonstrated that such anode materials are effective in inhibiting carbon deposition or sulfur poisoning. [9][10][11] So far the cell designs are exclusively electrolyte-supported when metal oxide anodes are employed.…”

Characterization of YSZ?YST composites for SOFC anodes

“…Furthermore, since any migration of Ti into the YSZ electrolyte would tend to make the YSZ electronically conductive, the excellent OCV measured on these cells demonstrates that solid-state reaction cannot have occurred on the length scale of the electrolyte. The fact that a dense YSZ electrolyte could be attached to the composite anode 5 5 was somewhat surprising since some thermal-expansion mismatch should be expected between the YSZ and YST50 layers over the very wide temperature range to which the bilayer was exposed in fabrication, 300 K to 1773 K, although an earlier report has also stated that La-doped SrTiO 3 has a similar CTE as YSZ [12]. The maximum power density improved significantly with the addition of ceria, increasing from 12 mW/cm 2 to 63 mW/cm 2 .…”

“…The obvious conclusion is that YST50 composite does not have adequate electronic conductivity. It should be noted that we did not attempt a hightemperature reduction, which previous work has shown to be necessary for achieving high conductivity in YST [12]. Fig.…”

“…While Ni anodes have demonstrated excellent performance in H 2 and syngas, they have serious limitations for direct utilization of hydrocarbons due to the fact that Ni catalyzes the formation of carbon fibers [2 -5]. By using alternative conductors, such as Cu [6,7], doped ceria [8][9][10], and other conducting oxides [11][12][13], a number of groups have demonstrated that direct utilization of hydrocarbons is possible. Oxides that are electronically conductive under reducing conditions are particularly intriguing for anode applications.…”