Low temperature thin film solid oxide fuel cells with nanoporous ruthenium anodes for direct methane operation

Takagi, Yuto; Lai, Bo‐Kuai; Kerman, Kian; Ramanathan, Shriram

doi:10.1039/c1ee01310f

Cited by 76 publications

(39 citation statements)

References 43 publications

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“…Unlike the highly granular RueCGO thin films deposited on YSZ/Si 3 N 4 /Si substrates, RueCGO anode films deposited on self-supported electrolytes exhibited a smoother feature. Differences in morphology when depositing anode films on a lithographically patterned structure of mSOFCs have been reported in previous works and possibly results from geometrical effects during sputter deposition and low thermal mass of the freestanding electrolyte membranes [8,9,28]. Table 2 summarizes deposition parameters and performance test results of fabricated RueCGO anode mSOFCs.…”

Section: Fabrication and Performance Testing Of Msofcsmentioning

confidence: 86%

“…In a recent work, we have demonstrated thin film mSOFC with peak performance of 450 mW cm À2 and an open circuit voltage of 0.71 V at 500 C with direct supply of weakly humidified methane as a fuel [9]. Nano-porous ruthenium (Ru) anodes were fabricated by physical vapor deposition on thin film mSOFCs with 8 mol% yttria-stabilized zirconia (YSZ) thin film electrolytes and porous Pt cathodes.…”

Section: Introductionmentioning

confidence: 99%

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Nanostructured ruthenium – gadolinia-doped ceria composite anodes for thin film solid oxide fuel cells

Takagi

Adam

Ramanathan

2012

Journal of Power Sources

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Section: Fabrication and Performance Testing Of Msofcsmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Nanostructured ruthenium – gadolinia-doped ceria composite anodes for thin film solid oxide fuel cells

Takagi

Adam

Ramanathan

2012

Journal of Power Sources

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“…Their power densities were measured in an external furnace or on a hot plate with pure hydrogen or hydrogen diluted with inert gases as fuel. A few publications report about anodes based on Pt, Pd or Ru, which were tested in fuels consisting of methane or a methane-air mixture reformed in situ on the anodes [17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

A thermally self-sustained micro-power plant with integrated micro-solid oxide fuel cells, micro-reformer and functional micro-fluidic carrier

Scherrer

Evans

Santis-Alvarez

et al. 2014

Journal of Power Sources

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Low temperature micro-solid oxide fuel cell (micro-SOFC) systems are an attractive alternative power source for small-size portable electronic devices due to their high energy efficiency and density. Here, we report on a thermally self-sustainable reformer -micro-SOFC assembly. The device consists of a micro-reformer bonded to a silicon chip containing 30 micro-SOFC membranes and a functional glass carrier with gas channels and screenprinted heaters for start-up. Thermal independence of the device from the externally powered heater is achieved by exothermic reforming reactions above 470 °C. The reforming reaction and the fuel gas flow rate of the n-butane/air gas mixture controls the operation temperature and gas composition on the micro-SOFC membrane. In the temperature range between 505 °C and 570 °C, the gas composition after the micro-reformer consists of 12 vol.% to 28 vol.% H 2 .An open-circuit voltage of 1.0 V and maximum power density of 47 mW cm -2 at 565 °C is achieved with the on-chip produced hydrogen at the micro-SOFC membranes.

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“…1,2 Mass transport in the electrodes is one of the critical problems that limits the electrochemical performance. 3 Electrodes fabricated with a large pore size have outstanding mass transport properties at the expense of active reaction sites (i.e.…”

Section: Introductionmentioning

confidence: 99%

The application of hierarchical structures in energy devices: new insights into the design of solid oxide fuel cells with enhanced mass transport

Bertei

et al. 2018

Energy Environ. Sci.

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a Mass transport can significantly limit the rate of reaction and lead to concentration polarisation in electrochemical devices, especially under the conditions of high operating current density. In this study we investigate hierarchically structured micro-tubular solid oxide fuel cells (MT-SOFC) fabricated by a phase inversion technique and quantitatively assess the mass transport and electrochemical performance improvement compared to a conventional tubular SOFC. We present pioneering work to characterise the effective mass transport parameters for the hierarchically porous microstructures by an integrated computed fluid dynamics simulation, assisted by multi-length scale 3D X-ray tomography. This has been historically challenging because either imaging resolution or field of view has to be sacrificed to compensate for the wide pore size distribution, which supports different transport mechanisms, especially Knudsen flow. Results show that the incorporation of radially-grown micro-channels helps to decrease the tortuosity factor by approximately 50% compared to the conventional design consisting of a spongelike structure, and the permeability is also improved by two orders of magnitude. When accounting for the influence of Knudsen diffusion, the molecule/wall collisions yield an increase of the tortuosity factor from 11.5 (continuum flow) to 23.4 (Knudsen flow), but the addition of micro-channels helps to reduce it down to 5.3. Electrochemical performance simulations using the measured microstructural and mass transport parameters show good agreement with the experimental results at elevated temperatures. The MT-SOFC anode displays 70% lower concentration overpotential, 60% higher power density (0.98 vs. 0.61 W cm À2 ) and wider current density window for maximum power density than the conventional design. Broader contextHierarchical materials are a popular choice not only for electrochemical energy devices such as fuel cells and batteries, but also for a range of functional materials including catalysts, diffusion media and membranes for waste processing. This study qualitatively and quantitatively illustrates the effectiveness of hierarchically structured pores in reducing gas transport resistance, providing new insights into advanced microstructure optimisation. Moreover, it is a common mistake in the modelling of hierarchical materials to assume the flow to be governed by continuum physics irrespective of the length scale, whereas in the region of finest structure, the molecule/wall collisions become dominant, which cannot be addressed by continuum physics. It is also impossible to define a relevant average pore size to describe the mass transport in these materials due to the wide pore size distribution. The integrated computed fluid dynamics (I-CFD) technique proposed by us for the first time herein, aims to overcome this problem and accurately characterise the effective mass transport in these complex hierarchical structures. The concept and techniques used in this study are believed to be of wide inter...

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Low temperature thin film solid oxide fuel cells with nanoporous ruthenium anodes for direct methane operation

Cited by 76 publications

References 43 publications

Nanostructured ruthenium – gadolinia-doped ceria composite anodes for thin film solid oxide fuel cells

Nanostructured ruthenium – gadolinia-doped ceria composite anodes for thin film solid oxide fuel cells

A thermally self-sustained micro-power plant with integrated micro-solid oxide fuel cells, micro-reformer and functional micro-fluidic carrier

The application of hierarchical structures in energy devices: new insights into the design of solid oxide fuel cells with enhanced mass transport

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