Nanostructured and functionally graded cathodes for intermediate temperature solid oxide fuel cells

Liu, Ying; Compson, Charles; Liu, Meilin

doi:10.1016/j.jpowsour.2004.06.035

Cited by 98 publications

(59 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A typical advantage of this is the accommodation of large thermal expansion coefficient (TEC) strains between electrolyte and cathode materials. This is overcome by a gradual change in composition over the graded layers [10][11][12]. This however is not a problem for the materials used in this study -L2N1 and L4N3 are wellmatched with the electrolyte used, La 0. microstructurally.…”

Section: Introductionmentioning

confidence: 95%

“…This however is not a problem for the materials used in this study -L2N1 and L4N3 are wellmatched with the electrolyte used, La 0. microstructurally. For the former it is known that polarisation resistances can be improved by having a composition with high ionic conductivity adjacent to the electrolyte, and grading to a composition with greater electronic conductivity as the thickness of the electrode is increased [10][11][12]14]. For the R-P phases used in this study this would correspond to a greater L2N1 content grading to a greater L4N3 content.…”

Section: Introductionmentioning

confidence: 95%

See 1 more Smart Citation

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

Woolley

Skinner

2014

Solid State Ionics

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 95%

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

Woolley

Skinner

2014

Solid State Ionics

View full text Add to dashboard Cite

show abstract

“…At the interface layer, as the particles get smaller, a larger number of triple phase boundaries (TPB) as the three-dimensional sites between LSM particles, YSZ electrolyte and gas-phase (O 2 ) or electrode surface sites along with higher porosity can be developed resulting in increasing the cathodic activity. Reports show that nanostructured electrodes dramatically reduce electrode/electrolyte interfacial polarization resistances and improve cell performance supporting that the microstructure close to the interface should be as fine as possible 26,39 . However, smaller particles can not always guarantee a higher activity since they are more capable to grow and to be sintered at working temperatures in real cell and fill the active sites 71 .…”

Section: Effect Of Precursor Solution Concentrationmentioning

confidence: 99%

“…adequate porosity for oxygen supply and transport while providing electrochemical reaction sites for oxygen reduction as well as a path for electrons to be transported from the cathode/electrolyte reaction sites to the surface of the cathode. Therefore, to achieve a balance between these two conflicting requirements for charge and mass transfer, graded electrode structures with a finer microstructure and porosity close to the electrolyte and coarser microstructure and larger porosity away from it has to be developed 26,27 .…”

Section: Research Objectives and Motivationmentioning

confidence: 99%

“…Most of the analysis reported in the literature is performed on compositionally graded LSM-YSZ cathodes 34 . In some of the proposed models, the porosity gradient through the cathode layer is also incorporated 26,32,[35][36][37] . It is of great interest that the grading will reduce the coefficient of thermal expansion (CTE) mismatch between the electrode and the electrolyte substrate resulting in improvement of adhesion, durability and mechanical stability of the cell components.…”

Section: Research Objectives and Motivationmentioning

confidence: 99%

See 1 more Smart Citation

Microstructure Sensitive Design and Processing in Solid Oxide Electrolyzer Cell

Garmestani¹,

Herring²

2009

View full text Add to dashboard Cite

SUMMARYThe aim of this study was to develop an inexpensive manufacturing process for deposition of functionally graded thin films of LSM oxides with porosity graded microstructures for use as IT-SOFCs cathode. The spray pyrolysis method was chosen as a low-temperature processing technique for deposition of porous LSM films onto dense YSZ substrates. The effort was directed toward the optimization of the processing conditions for deposition of high quality LSM films with variety of morphologies in the range of dense to porous microstructures. Results of optimization studies of spray parameters revealed that the substrate surface temperature is the most critical parameter influencing the roughness and morphology, porosity, cracking and crystallinity of the film. Physical and chemical properties of deposited thin films such as porosity, morphology, phase crystallinity and compositional homogeneity have shown to be extensively dependent on the preparation conditions. Detailed analysis of the film formation mechanisms have been discussed in this work. It is suggested that using volatile metal-organic precursors as in CVD would alter the film formation mechanism to MOCVD process in which films of high quality can be processed. Novel electrode microstructures currently include a graded microstructure wherein the large pores are made close to the surface in outer layers for maximum mass transport into the electrode structure and smaller pores and particles close to the electrolyte interface would create maximum number of active reaction sites. Taking the advantage of simplicity of spray pyrolysis technique combined with using metal-organic compounds, the conventional ultrasonic spray system was upgraded to a novel system whereby highly crystalline multiMicrostructure Sensitive Design for Materials in Solid Oxide Electrolyzer Cell, Garmestani vi layered porosity graded LSM cathode with columnar morphology with good electrical conductivity in the range of 500-700 °C was fabricated through a multi-step spray and via optimizing spray parameters. This achievement for the current graded LSM cathode would allow its use in IT-SOFCs.Microstructure Sensitive Design for Materials in Solid Oxide Electrolyzer Cell, Garmestani 7

show abstract

Facile Synthesis of Optically Functional, Highly Organized Nanostructures: Dye–Surfactant Complexes

Faul

Antonietti

2002

Chem. Eur. J.

View full text Add to dashboard Cite

Pulsed Laser Deposition (PLD) was used to prepare thin films with the nominal composition La0.58Sr0.4Co0.2Fe0.8O3‐δ (LSCF). The thin film microstructure was investigated as a function of PLD deposition parameters such as: substrate temperature, ambient gas pressure, target‐to‐substrate distance, laser fluence and frequency. It was found that the ambient gas pressure and the substrate temperature are the key PLD process parameters determining the thin film micro‐ and nanostructure. A map of the LSCF film nanostructures is presented as a function of substrate temperature (25–700 °C) and oxygen background pressure (0.013–0.4 mbar), with film structures ranging from fully dense to highly porous. Fully crystalline, dense, and crack‐free LSCF films with a thickness of 300 nm were obtained at an oxygen pressure lower than 0.13 mbar at a temperature of 600 °C. The obtained knowledge on the structure allows for tailoring of perovskite thin film nanostructure, e.g., for solid oxide fuel cell cathodes. A simple geometrical model is proposed, allowing estimation of the catalytic active surface area of the prepared thin films. It is shown that voids at columnar grain boundaries can result in an increase of the surface area by approximately 25 times, when compared to dense flat films.

show abstract

Nanostructured and functionally graded cathodes for intermediate temperature solid oxide fuel cells

Cited by 98 publications

References 22 publications

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

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

Microstructure Sensitive Design and Processing in Solid Oxide Electrolyzer Cell

Facile Synthesis of Optically Functional, Highly Organized Nanostructures: Dye–Surfactant Complexes

Contact Info

Product

Resources

About