Limits...
A micro-nano porous oxide hybrid for efficient oxygen reduction in reduced-temperature solid oxide fuel cells.

- Sci Rep (2012)

Bottom Line: Tremendous efforts to develop high-efficiency reduced-temperature (≤ 600°C) solid oxide fuel cells are motivated by their potentials for reduced materials cost, less engineering challenge, and better performance durability.A key obstacle to such fuel cells arises from sluggish oxygen reduction reaction kinetics on the cathodes.Here we reported that an oxide hybrid, featuring a nanoporous Sm(0.5)Sr(0.5)CoO(3-δ) (SSC) catalyst coating bonded onto the internal surface of a high-porosity La(0.9)Sr(0.1)Ga(0.8)Mg(0.2)O(3-δ) (LSGM) backbone, exhibited superior catalytic activity for oxygen reduction reactions and thereby yielded low interfacial resistances in air, e.g., 0.021 Ω cm(2) at 650°C and 0.043 Ω cm(2) at 600°C.

View Article: PubMed Central - PubMed

Affiliation: CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics , Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050, P. R. China.

ABSTRACT
Tremendous efforts to develop high-efficiency reduced-temperature (≤ 600°C) solid oxide fuel cells are motivated by their potentials for reduced materials cost, less engineering challenge, and better performance durability. A key obstacle to such fuel cells arises from sluggish oxygen reduction reaction kinetics on the cathodes. Here we reported that an oxide hybrid, featuring a nanoporous Sm(0.5)Sr(0.5)CoO(3-δ) (SSC) catalyst coating bonded onto the internal surface of a high-porosity La(0.9)Sr(0.1)Ga(0.8)Mg(0.2)O(3-δ) (LSGM) backbone, exhibited superior catalytic activity for oxygen reduction reactions and thereby yielded low interfacial resistances in air, e.g., 0.021 Ω cm(2) at 650°C and 0.043 Ω cm(2) at 600°C. We further demonstrated that such a micro-nano porous hybrid, adopted as the cathode in a thin LSGM electrolyte fuel cell, produced impressive power densities of 2.02 W cm(-2) at 650°C and 1.46 W cm(-2) at 600°C when operated on humidified hydrogen fuel and air oxidant.

Show MeSH
Cross-sectional SEM micrographs showing the structure of the micro-nano porous SSC/LSGM hybrid.(a) A low magnification survey of the hybrid. (b) A high magnification view of the SSC catalyst.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3375499&req=5

f1: Cross-sectional SEM micrographs showing the structure of the micro-nano porous SSC/LSGM hybrid.(a) A low magnification survey of the hybrid. (b) A high magnification view of the SSC catalyst.

Mentions: Note that these SSC infiltrates play dual roles in the porous LSGM backbones: catalyzing oxygen reduction reaction and collecting the electrical current. Well-connected coatings are mandatory for effective implementation of both functions, and can be readily attained at higher catalyst loadings via multiple impregnation/calcination cycles. Fig. 1a shows an SEM micrograph of the SSC/LSGM hybrid at VSSC = 12.9% that exhibited substantially improved phase connectivity. In the meanwhile, increasing the number of impregnation/calcination cycles increased the catalyst coating thickness on the pore walls as well. For example, the SSC particles increased to ≈ 100 nm at VSSC = 12.9%, as shown in Fig. 1b. Such an increase in the catalyst particle size can be ascribed to repeated calcination cycles that inevitably caused agglomeration and coarsening of these nanoparticulates. Nevertheless, the cost-effective and manufacturing-scalable chemical solution impregnation technology enabled the formation of nanoporous and well intra-connected SSC electrocatalyst coatings on the internal surfaces of the porous LSGM backbones.


A micro-nano porous oxide hybrid for efficient oxygen reduction in reduced-temperature solid oxide fuel cells.

- Sci Rep (2012)

Cross-sectional SEM micrographs showing the structure of the micro-nano porous SSC/LSGM hybrid.(a) A low magnification survey of the hybrid. (b) A high magnification view of the SSC catalyst.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3375499&req=5

f1: Cross-sectional SEM micrographs showing the structure of the micro-nano porous SSC/LSGM hybrid.(a) A low magnification survey of the hybrid. (b) A high magnification view of the SSC catalyst.
Mentions: Note that these SSC infiltrates play dual roles in the porous LSGM backbones: catalyzing oxygen reduction reaction and collecting the electrical current. Well-connected coatings are mandatory for effective implementation of both functions, and can be readily attained at higher catalyst loadings via multiple impregnation/calcination cycles. Fig. 1a shows an SEM micrograph of the SSC/LSGM hybrid at VSSC = 12.9% that exhibited substantially improved phase connectivity. In the meanwhile, increasing the number of impregnation/calcination cycles increased the catalyst coating thickness on the pore walls as well. For example, the SSC particles increased to ≈ 100 nm at VSSC = 12.9%, as shown in Fig. 1b. Such an increase in the catalyst particle size can be ascribed to repeated calcination cycles that inevitably caused agglomeration and coarsening of these nanoparticulates. Nevertheless, the cost-effective and manufacturing-scalable chemical solution impregnation technology enabled the formation of nanoporous and well intra-connected SSC electrocatalyst coatings on the internal surfaces of the porous LSGM backbones.

Bottom Line: Tremendous efforts to develop high-efficiency reduced-temperature (≤ 600°C) solid oxide fuel cells are motivated by their potentials for reduced materials cost, less engineering challenge, and better performance durability.A key obstacle to such fuel cells arises from sluggish oxygen reduction reaction kinetics on the cathodes.Here we reported that an oxide hybrid, featuring a nanoporous Sm(0.5)Sr(0.5)CoO(3-δ) (SSC) catalyst coating bonded onto the internal surface of a high-porosity La(0.9)Sr(0.1)Ga(0.8)Mg(0.2)O(3-δ) (LSGM) backbone, exhibited superior catalytic activity for oxygen reduction reactions and thereby yielded low interfacial resistances in air, e.g., 0.021 Ω cm(2) at 650°C and 0.043 Ω cm(2) at 600°C.

View Article: PubMed Central - PubMed

Affiliation: CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics , Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050, P. R. China.

ABSTRACT
Tremendous efforts to develop high-efficiency reduced-temperature (≤ 600°C) solid oxide fuel cells are motivated by their potentials for reduced materials cost, less engineering challenge, and better performance durability. A key obstacle to such fuel cells arises from sluggish oxygen reduction reaction kinetics on the cathodes. Here we reported that an oxide hybrid, featuring a nanoporous Sm(0.5)Sr(0.5)CoO(3-δ) (SSC) catalyst coating bonded onto the internal surface of a high-porosity La(0.9)Sr(0.1)Ga(0.8)Mg(0.2)O(3-δ) (LSGM) backbone, exhibited superior catalytic activity for oxygen reduction reactions and thereby yielded low interfacial resistances in air, e.g., 0.021 Ω cm(2) at 650°C and 0.043 Ω cm(2) at 600°C. We further demonstrated that such a micro-nano porous hybrid, adopted as the cathode in a thin LSGM electrolyte fuel cell, produced impressive power densities of 2.02 W cm(-2) at 650°C and 1.46 W cm(-2) at 600°C when operated on humidified hydrogen fuel and air oxidant.

Show MeSH