Functionally graded composite La 2 NiO 4+δ and La 4 Ni 3 O 10−δ solid oxide fuel cell cathodes

Abstract

Functionally graded electrodes have been fabricated from members of the (LaNiO 3 ) n LaO RuddlesdenPopper family. These consist of a thin compact layer of La 2 NiO 4+δ deposited on the electrolyte, topped by a thicker porous La 2 NiO 4+δ +La 4 Ni 310-δ composite layer, completed by a thin porous La 4 Ni 3 O 10-δ layer acting as a current collector. The microstructure and electrochemical role of these layers is discussed in detail. It was found that using a 50:50 wt.% mix in the composite layer gave the best performance; ASRs at 500, 550, 600, 650, and 700 °C were 15.6, 5.53, 2.29, 1.06 and 0.53 Ωcm 2 respectively. This represents high performance for this class of material, particularly notable at the lower-end of the temperature range. As such this grading process is an attractive proposition for further research towards lowering the operating temperature of SOFCs.

Advances in Cathode Materials for Solid Oxide Fuel Cells: Complex Oxides without Alkaline Earth Metal Elements

“…[ 432 ] (three layers) was prepared. [ 433 ] A thin compact La 2 NiO 4+ δ layer with good sintering capability was adjacent to the electrolyte. This improved the electrolyte/electrode contact as well as provided more active sites for oxygen reduction and incorporation.…”

Novel La2-x Cu x NiO4±δ /La4Ni3O10-δ composite materials for intermediate temperature solid oxide fuel cells, IT-SOFC

“…Recently, Woolley et al [22,23] have studied the properties of new composite materials such as cathode for SOFCs consist of La 2 NiO 4±δ (L2N1) and La 4 Ni 3 O 10-δ (L4N3). A mixture of 50:50 wt% between La 2 NiO 4±δ and La 4 Ni 3 O 10-δ improved its electrochemical performance with an ASR at 700°C of 0.62 Ω cm 2 with La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ (LSGM8282) electrolyte.…”

“…The formation of a composite leads to improved performance aver the single phases, particularly above 600°C [22]. The same authors have studied a new architecture, which is composed as follows: − a thin compact L2N1 (La 2 NiO 4±δ ) layer adjacent to the electrolyte improving the electrolyte/ electrode contact and providing more active sites for oxygen reduction and incorporation; − a thicker more porous L2N1 (La 2 NiO 4±δ )+L4N3 (La 4 Ni 3 O 10-δ ) composite, for which a 50:50 wt% mixture gave the best performance [23]. The outer layer of porous L4N3 acts as a low cost current collector.…”

“…Compared to two recent studies dedicated to only one composite material (L2N1+L4N3) [22,23], the originality of this work is to synthesize and analyse a series of composite materials constituted by La 2 NiO 4±δ , doped in the lanthanum site by copper, and La 4 Ni 3 O 10-δ , with a weight percentage of 50:50 wt%, as cathode materials for SOFC. Doping by copper aims at improving the electrochemical performance of the material and using La 4 Ni 3 O 10-δ may contribute to stabilize the cathode materials.…”

Investigation of thin perovskite layers between cathode and doped ceria used as buffer layer in solid oxide fuel cells

“…Recently, much thinner functional layers between the cathode/electrolyte were found to improve fuel cell performance. Such a layer has been prepared by dip-coating (2 μm thick) by Rieu [13] and by screen printing (5 μm thick) by Woolley [14], and it decreased polarization resistance of a La 2 NiO 4+δ electrode. Hildenbrand reported an improvement of the cathode/electrolyte interface for La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) and La 2 NiO 4+δ cathodes using a thin dense layer obtained by pulsed laser deposition [15,16].…”