Preparation of SOFC Cathodes by Infiltration into LSF-YSZ Composite Scaffolds

Cheng, Yuan; Yu, Anthony S.; Li, Xiaoyan; Oh, Tae-Sik; Vohs, John M.; Gorte, Raymond J.

doi:10.1149/2.0171602jes

Cited by 29 publications

(35 citation statements)

References 27 publications

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“…For the later strategy, a relatively novel method of in-situ forming nano-sized electrocatalysts by solution infiltration in a porous structure is often used. The infiltration of electro-catalyst precursor solutions into a conventional solid oxide cell fuel electrode or oxygen electrode, or into a specially developed scaffold has shown to be very efficient in improving the electrode performance in the short term 8,[15][16][17][18][19] . Whereas for long-term tests, only few operations of infiltrated electrodes tested in either fuel cell mode or electrolysis mode have been reported, focusing on oxygen electrode infiltration mainly 17,[20][21][22] .…”

Section: Introductionmentioning

confidence: 99%

Boosting the performance and durability of Ni/YSZ cathode for hydrogen production at high current densities via decoration with nano-sized electrocatalysts

et al. 2019

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Section: Introductionmentioning

confidence: 99%

Boosting the performance and durability of Ni/YSZ cathode for hydrogen production at high current densities via decoration with nano-sized electrocatalysts

et al. 2019

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“…11,12 In some cases, the porous layers were infiltrated with La 0.6 Sr 0. 4 3 . Each infiltration cycle consisted of filling the pores with the precursor solution, followed by drying and calcination in air at 723 K to decompose the nitrates.…”

Section: Journal Of the Electrochemical Society 164 (6) F525-f529 (2mentioning

confidence: 99%

An Investigation of LSF-YSZ Conductive Scaffolds for Infiltrated SOFC Cathodes

Cheng

Wilson

et al. 2017

J. Electrochem. Soc.

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Porous composites of Sr-doped LaFeO 3 (LSF) and yttria-stabilized zirconia (YSZ) were investigated as conductive scaffolds for infiltrated SOFC cathodes with the goal of producing scaffolds for which only a few perovskite infiltration steps are required to achieve sufficient conductivity. While no new phases form when LSF-YSZ composites are calcined to 1623 K, shifts in the lattice parameters indicate Zr can enter the perovskite phase. Measurements on dense, LSF-YSZ composites show that the level of Zr doping depends on the Sr:La ratio. Because conductivity of undoped LSF increases with Sr content while both the ionic and electronic conductivities of Zr-doped LSF decrease with the level of Zr in the perovskite phase, there is an optimum initial Sr content corresponding to La 0.9 Sr 0.1 FeO 3 (LSF91). Although scaffolds made with 100% LSF had a higher conductivity than scaffolds made with 50:50 LSF-YSZ mixtures, the 50:50 mixture provides the optimal interfacial structure with the electrolyte and sufficient conductivity, providing the best cathode performance upon infiltration of La 0.6 Sr 0. 1 First, the NiO-YSZ composite that will become the anode is co-fired together with the YSZ electrolyte to produce a dense electrolyte. Next, a doped-ceria layer is screen printed onto the cathode side of the dense electrolyte and fired to produce a doped-ceria film that will act as a barrier layer to prevent reaction of the LSCF with the YSZ. Finally, LSCF is screen printed onto the doped-ceria film and fired to a temperature sufficient to give the LSCF structural integrity and good adhesion to the electrolyte. Obviously, there would be significant advantages to reducing the number of fabrication and calcination steps.An alternative method for preparing high-performance LSCF cathodes involves preparing a porous YSZ scaffold on the cathode side of the electrolyte, followed by infiltration of LSCF nanoparticles or precursor salts.2 The NiO-YSZ anode, the YSZ electrolyte, and the YSZ scaffold layers can all be co-fired, and the doped-ceria barrier layer may not be needed.3 However, the infiltration method is not widely used because many infiltration steps are typically required to provide sufficient cathode conductivity.Recently, it was suggested that the number of infiltration steps could be greatly reduced if the porous scaffold was itself electronically conductive. 4 Infiltration is still required to add LSCF into the scaffold to carry out the oxygen-exchange reactions but the amounts required for the catalytic reaction can be much smaller. To implement this approach, it is necessary to find a conductive oxide that will not react with YSZ at the temperatures required to produce a dense electrolyte. Because Sr-doped LaFeO 3 (LSF) has been shown to be relatively unreactive with YSZ, 5-7 our group focused on preparing LSF-YSZ scaffolds for this application.4 Co-firing LSF and YSZ did not lead to new phases but a shift in the lattice parameter for the perovskite phase suggested that some Zr was entering the perovskite lattice. ...

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“…The third type of electrodes is purposely proposed to reduce the infiltration cycles because the dual‐phase backbone can provide a certain electronic conduction. For example, Cheng et al infiltrated LSCF into the LSCF‐YSZ backbone for the purpose of reducing the infiltration cycles required to make a conductive network …”

Section: Introductionmentioning

confidence: 99%

“…For example, Cheng et al infiltrated LSCF into the LSCF-YSZ backbone for the purpose of reducing the infiltration cycles required to make a conductive network. 11 It has been reported that the infiltrated nanostructure can enhance electrode performance. Jiang et al found that GDC infiltrated LSM (lanthanum strontium manganite) cathode reached a polarization resistance of 0.21 Ω cm 2 , about 56 times lower than that of LSM cathode at the same temperature of 700°C.…”

Section: Introductionmentioning

confidence: 99%

A numerical study of infiltrated solid oxide fuel cell electrode with dual‐phase backbone

2018

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Summary Three‐dimensional microstructure of infiltrated solid oxide fuel cell electrodes with dual‐phase backbone is simulated numerically. This work employs LSM (lanthanum strontium manganite) infiltrated LSM yttria‐stabilized zirconia composite electrodes as an example. Important geometric properties, including percolation probability of LSM, total and percolated three‐phase boundary (TPB) lengths, and total and percolated surface areas of LSM, are calculated under various LSM nanoparticle loadings. One important finding is that compared with pure yttria‐stabilized zirconia backbone, dual‐phase backbone results in lower TPB length and has little impact on the surface area of LSM particles. Therefore, the addition of LSM backbone may be ineffective, even negative in promoting the electrode performance, however, can significantly reduce the LSM infiltration threshold loading to form a percolating network. The trade‐off between decreasing infiltration cycle and increasing TPB length demands an optimized content of LSM in backbone.

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Preparation of SOFC Cathodes by Infiltration into LSF-YSZ Composite Scaffolds

Cited by 29 publications

References 27 publications

Boosting the performance and durability of Ni/YSZ cathode for hydrogen production at high current densities via decoration with nano-sized electrocatalysts

Boosting the performance and durability of Ni/YSZ cathode for hydrogen production at high current densities via decoration with nano-sized electrocatalysts

An Investigation of LSF-YSZ Conductive Scaffolds for Infiltrated SOFC Cathodes

A numerical study of infiltrated solid oxide fuel cell electrode with dual‐phase backbone

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