Effect of Contact between Electrode and Interconnect on Performance of SOFC Stacks

Guan, Wanbing; Zhai, Huijuan; Jin, Le; Li, T. S.; Wang, W. G.

doi:10.1002/fuce.201000176

Cited by 46 publications

(17 citation statements)

References 13 publications

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“…[11][12][13] Furthermore, the quantitative contributions of the resistance sources of components to stack performance were obtained by our group. We concluded that stack performance is signifi cantly affected by cell performance itself when excellent stack sealing and contact among internal components are provided.…”

mentioning

confidence: 99%

In‐Situ Investigation of Quantitative Contributions of the Anode, Cathode, and Electrolyte to the Cell Performance in Anode‐Supported Planar SOFCs

Guan

Wang

et al. 2014

Advanced Energy Materials

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performance, except for the materials of components when the stack is sealed properly. [11][12][13] Furthermore, the quantitative contributions of the resistance sources of components to stack performance were obtained by our group. We concluded that stack performance is signifi cantly affected by cell performance itself when excellent stack sealing and contact among internal components are provided. [ 14 ] Therefore, further improvement of cell performance (i.e., reducing cell resistance) and unit cell stability is crucial for SOFC stacks.Anode-supported planar SOFCs are widely used because of their superior performance and multi-layered structure that comprises several components (supported anode, anode function layer, electrolyte, and active cathode). [ 15,16 ] Thus, a quantitative understanding of how the cell components affect cell performance can function as a guide in optimizing cell performance. Accordingly, traditional methods, such as electrochemical impedance spectroscopy (EIS) and current-voltage ( I -V ) measurement, have been generally applied to investigate factors that affect cell performance using external probes placed on both sides of a unit cell. [17][18][19][20] However, traditional measurements do not distinguish between the quantitative effects of cell components on cell performance and degradation mechanisms. These effects result from complex physical and chemical processes at the triple-phase boundary (TPB) within the cell. Meanwhile, common I -V measurement or EIS can only obtain variation patterns in a unit cell rather than in the individual cell components. [ 21,22 ] Thus, special voltage probes embedded into the internal TPB are necessary to measure cell components (i.e., anode, electrolyte, and cathode) individually and to obtain their quantitative contributions on cell performance. However, for anode-supported planar SOFCs, the introduction of an internal voltage probe at the TPB within the cell is an immense challenge because of the thin electrolyte, [ 17 ] the active anode, [ 23 ] and the active cathode. [ 24 ] Consequently, an in situ investigation of the quantitative contributions of components (i.e., anode, electrolyte, and cathode) to cell performance has not been reported for anode-supported planar SOFCs.In the present work, a novel in situ measurement technique is developed according to the conventional structure of anode-supported SOFCs. Pt voltage probes are embedded into A novel method that embeds Pt voltage probes into the triple-phase boundary (TPB) is developed. Moreover, the quantitative contributions of the anode, the cathode, and the electrolyte to cell performance are investigated in situ for anode-supported planar solid oxide fuel cells (SOFCs). The voltage and maximum output power density (MOPD) measured by the probes, which are placed on both sides of the electrolyte, account for 97.3% and 94.4%, respectively, of those of the cell during the instantaneous current-voltage testing. When the stack is discharged at 0.32 A cm −2 for 200 h, the voltage drops of the an...

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mentioning

confidence: 99%

In‐Situ Investigation of Quantitative Contributions of the Anode, Cathode, and Electrolyte to the Cell Performance in Anode‐Supported Planar SOFCs

Guan

Wang

et al. 2014

Advanced Energy Materials

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“…2b) and c) shows that the boundaries of cathode contact for cells #1 and 2 can be clearly distinguished. Based on our previous results [17], the difference in power density between repeating units 1 and 2 is mainly due to the difference in electron transfer resistance at the cathode side. .…”

Section: Resultsmentioning

confidence: 76%

“…For instance, new electrode materials [5][6][7][8] and nanostructures [9][10][11] have been reported, which resulted in a maximum power density ≥ 2.9 W•cm −2 at 650 o C with humidified 3% H 2 as fuel and air as oxidant. On the contrary, the power density of an SOFC stack is generally less than 0.6 Wcm −2 [12][13][14][15], which determined by the contact layer between the cathode and the interconnect [16][17][18][19][20]. Because of the high-temperature oxidation atmosphere at the cathode side, researchers initially attempted to print noble metal slurry on the cathode as a current collector [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Mechanism of the cathode current collector on cell performance in a solid oxide fuel cell stack

Guan¹,

Wang²,

Zhou

2017

Journal of Power Sources

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In this work, we report a new design of the contact layer to investigate the significance and mechanism for the cathodic current collection. The single cells in a stack are covered with Ag paste on the cathode side, which exhibit slightly higher power density than that of the cell partially covered with Ag paste. The Ag paste is applied as a current-collecting layer on the cathode side at the corresponding position in contact with the punctuate structure of the interconnect. The difference in power densities between the two single cells is due to the in-plane electron transfer on the cathode surface. When the structure of the interconnect is changed from a convex punctuate structure to liner strips, the cell performance is governed by both gas flow rate and in-plane electron transfer; however, the latter plays a more important role than the gas flow rate. An appropriate arrangement of current collection at the cathode side is necessary to improve current collection and thus the cell performance inside the SOFC stack.

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“…The single cell active area is 70cm 2 . The detailed parameters of cells can be seen elsewhere (11)(12)(13). The Fe-16Cr alloy was used Figure 4 shows the result of a 2-cell stack working under SOEC and SOFC mode alternately.…”

Section: Durability Of High Temperature Seam Electrolysis For Hydrogementioning

confidence: 99%

Achieving Hydrogen Production through Solid Oxide Electrolyzer Stack by High Temperature Electrolysis

Jin

Guan

et al. 2012

ECS Trans.

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Based on the reversal reaction of solid oxide fuel cells (SOFC), high temperature electrolysis (HTE) is an effective way for large-scale and low cost hydrogen production. The problem restricted the development for HTE is the stability of steam supplying, conversion rate of steam to H 2 , hydrogen production rate and the durability of solid oxide electrolysis cells (SOECs) and stacks. To solve the problems mentioned above, a steam and gas fogged mixer (SGFM) was designed which can be used for not only experimental HTE but also large-scale hydrogen production. A 30-cell SOEC stack was tested combined with the mixer for 1000 hours at 800 o C with an electrolysis current of 4 A. The steam-to-hydrogen conversion (SC) rate was calculated to be 70% by determining the water amount at the inlet and outlet of the hydrogen electrode. The hydrogen production rate was 99.3 NL/h.

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Effect of Contact between Electrode and Interconnect on Performance of SOFC Stacks

Cited by 46 publications

References 13 publications

In‐Situ Investigation of Quantitative Contributions of the Anode, Cathode, and Electrolyte to the Cell Performance in Anode‐Supported Planar SOFCs

In‐Situ Investigation of Quantitative Contributions of the Anode, Cathode, and Electrolyte to the Cell Performance in Anode‐Supported Planar SOFCs

Mechanism of the cathode current collector on cell performance in a solid oxide fuel cell stack

Achieving Hydrogen Production through Solid Oxide Electrolyzer Stack by High Temperature Electrolysis

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