Optimization of the Interconnect Ribs for a Cathode-Supported Solid Oxide Fuel Cell

Summary Reversible solid oxide fuel cells (rSOFCs) may be applied to store and generate electrical energy in a reversible mode. This technique is promising to balance the conflict between intermittent power supply and demand in a sustainable way. One of the limitations of the development of rSOFCs is the high cost of storage and usage of pure H2, which may be solved by employing syngas as the fuel. The performance of rSOFCs depends on the development of bifunctional materials, cell design, and operation optimization, which are often investigated and predicted by the cost‐effective approach of mathematical modeling. However, the modeling of dual‐mode rSOFCs involving co‐redox reactions with syngas is not well developed. In this study, a two‐dimensional (2D) single‐channel model of an rSOFC is developed. The novelty of this model is that the multiphysics transport processes are fully coupled and solved with the reversible water‐gas shift reaction with syngas and the electrochemical reactions. The effects of the operating conditions and design parameters (eg, electrode thickness) are considered, with the aim of providing guidelines to optimize the design and operation of reversible cells. It is concluded that the thickness of the electrode has a larger impact on the water‐gas shift reaction than on the electrochemical reaction in both the gas diffusion and reaction regions. The C/H element ratio of syngas has a negative correlation with power output, but the distributions of current and gas species may be improved in both modes. A higher operating temperature improves the performance in both modes but has a more substantial effect in the electrolysis mode. The specific design and operating schemes favored in different modes should be balanced in the reversible mode.

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“…The effective conductivity of electrons and irons ( σ e,eff and σ ion,eff ) can be written as follows:

k_{e / italicion}^{eff} = k_{e / italicion} \times {(\frac{φ_{e / italicion} - 0.294}{1 + \frac{ε}{1 + ε} - 0.294})}^{2},

…”

Section: Model Descriptionmentioning

confidence: 99%

“…The effective conductivity of electrons and irons (σ e,eff and σ ion,eff ) can be written as follows 68 :…”

Section: Electron and Ion Transportmentioning

confidence: 99%

CFD modeling and performance comparison of solid oxide fuel cell and electrolysis cell fueled with syngas

et al. 2018

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“…In the past decade, low cost, clean and high efficiency energy conversation and storage devices, such as fuel cells [1], batteries [2] and super-capacitors [3], have been receiving more and more attentions. Solid oxide fuel cell (SOFC) has being recognized as a promising energy conservation device due to its efficiency [4] and capability to work with various fuels [5].…”

Section: Introductionmentioning

confidence: 99%

The Geometry Effect of Cathode/Anode Areas Ratio on Electrochemical Performance of Button Fuel Cell Using Mixed Conducting Materials

Chen

Ding

et al. 2018

Energies

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Intermediate temperature (IT) fuel cells using mixed conducting materials have been reported by many researchers by adopting different compositions, microstructures, manufacture processes and testing conditions. Most i op -V op relationships of these button electrochemical devices are experimentally achieved based on anode or cathode surface area (i.e., A an = A ca ). In this paper, a 3D multi-physics model for a typical IT solid oxide fuel cell (SOFC) that carefully considers detail electrochemical reaction, electric leakage, and e − , ion and gas transporting coupling processes has been developed and verified to study the effect of A ca /A an on button cell i op -V op performance. The result shows that the over zone of the larger electrode can enhance charges and gas transport capacities within a limited scale of only 0.03 cm. The over electrode zone exceed this width would be inactive. Thus, the active zone of button fuel cell is restricted within the smaller electrode area min(A an , A ca ) due to the relative large disc radius and thin component layer. For a specified V op , evaluating the responded i op by dividing output current I op with min(A an , A ca ) for a larger value is reasonable to present real performance in the current device scale of cm. However, while the geometry of button cells or other electrochemical devices approach the scale less than 100 µm, the effect of over electrode zone on electrochemical performance should not be ignored. Energies 2018, 11, 1875 2 of 16 within mixed conducting CeO 2−x electrode [12]. S. Wang et al. compared the performances of various LSCF-based cathodes and found that LSCF-SDC exhibited a larger activation overpotential than did the single-phase LSCF cathode [13]. More interestingly, the LSM-coated LSCF composite electrode was reported to exhibit a lower activation overpotential compared with that in a pure LSCF cathode [13]. Furthermore, proton conducting oxides [14], such as BaZr 0.7 Pr 0.1 Y 0.2 O 3_d [15] and BaZr 0.1 Ce 0.7 Y 0.2 O 3_d [16] were also greatly invented to be used in IT-SOFCs because of their low activation energy and high ionic conductivity around IT-range.Generally, the electrochemical reaction processed within an IT-SOFC using mixed conducting materials or proton conducting oxides are very different from those using conventional composite electrodes [17]. Taking the cathode of LSCF-SDC/SDC/NI-SDC IT-SOFC using mixed conducting materials as an example [13], the electrochemically active sites not only can be taken placed around the percolated three phase boundary sites (i.e., LSCF-SDC-pores and LSCF-dense electrolyte interfaces), but also can happen around the percolated double phase boundary sites (e.g., LSCF-pore) [18]. Up to now, many IT-SOFC button cells using the mixed conducting materials have been reported by many researchers by adopting different compositions (or materials), volume fractions, microstructure parameters, manufacture processes, operating conditions and different cell geometry sizes. It is interesting to note that differe...

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“…Yuan et al [4] have found through numerical simulations, that the mass transfer rate, aspect ratio and base angle have significant effects on the thermal-hydraulic parameters. Kong et al [5] and Liu et al [6] optimized the size of the gas channel for cathode-supported SOFCs and proton-conductive SOFCs with a direct interconnector. Nguyen et al [7] proposed a ribbed interconnector SOFC.…”

Section: Introductionmentioning

confidence: 99%

Electrical Performance and Carbon Deposition Differences between the Bi-Layer Interconnector and Conventional Straight Interconnector Solid Oxide Fuel Cell

Yan

Pei

Chen³

et al. 2014

Energies

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Carbon deposition considered in a solid oxide fuel cell (SOFC) model may be influenced by the operating voltage, inlet water/methane ratio, working temperature and pressure, inlet molar fraction of fuel and so on. The effects of these parameters in a planar SOFC implementing a novel bi-layer interconnector are not well understood. This paper is focused on the numerical study of carbon deposition and electrical performance of a bi-layer interconnector planar SOFC. The results illustrate that the electrical performance of the bi-layer interconnector SOFC is 11% higher than that of the conventional straight interconnector SOFC with initial state. After 120 days of operation, the electrical performance of the bi-layer interconnector SOFC has a slight decrease and more carbon deposit because of the increased electrochemical reaction rate. However, these differences minimize if higher operating voltages are involved.

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Optimization of the Interconnect Ribs for a Cathode-Supported Solid Oxide Fuel Cell

Cited by 39 publications

References 47 publications

CFD modeling and performance comparison of solid oxide fuel cell and electrolysis cell fueled with syngas

CFD modeling and performance comparison of solid oxide fuel cell and electrolysis cell fueled with syngas

The Geometry Effect of Cathode/Anode Areas Ratio on Electrochemical Performance of Button Fuel Cell Using Mixed Conducting Materials

Electrical Performance and Carbon Deposition Differences between the Bi-Layer Interconnector and Conventional Straight Interconnector Solid Oxide Fuel Cell

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