Effect of electrode microstructure on gas-phase diffusion in solid oxide fuel cells

Sung Pil Yoon; Suk Woo Nam; Jonghee Han; Tae Hoon Lim; Seong Ahn Hong; Sang Hoon Hyun

doi:10.1016/j.ssi.2003.10.010

Effect of electrode microstructure on gas-phase diffusion in solid oxide fuel cells

Sung Pil Yoon, Suk Woo Nam, Jonghee Han, Tae Hoon Lim, Seong Ahn Hong, Sang Hoon Hyun

Research output: Contribution to journal › Article › peer-review

43 Citations (Scopus)

Abstract

The relation between electrode microstructure and gas diffusion has been investigated with different morphologies of Pt electrodes by using AC impedance techniques. The measurements were carried out at temperatures of 873-1273 K and oxygen partial pressure (P_O2) of 0.01-1 atm. Gas-phase diffusion was observed only for high-performance electrodes at the high-temperature (1073-1273 K) and low-oxygen-partial-pressure regions (<0.1 atm P _O2). Considering the physical and electrochemical characteristics of impedance arcs, it was found that the arc at the frequency of below 1 Hz was related to gas conversion resistance, while the arc at the frequency of around 10 Hz represented pore diffusion resistance through the current-collecting part. For a thick electrode with a low porosity, however, gas diffusion resistance through pores of an electrode was observed at a frequency of around 100 Hz. From the results of a comparison of electrode performances with different electrode microstructures, electrochemical reaction sites (ERS) are supposed to be located at the peripheral line of Pt and YSZ as well as the Pt/YSZ interfaces where reaction gas can easily diffuse.

Original language	English
Pages (from-to)	1-11
Number of pages	11
Journal	Solid State Ionics
Volume	166
Issue number	1-2
DOIs	https://doi.org/10.1016/j.ssi.2003.10.010
Publication status	Published - 2004 Jan 15

Keywords

Electrochemical reaction site
Electrode microstructure
Gas-phase diffusion
Impedance analysis
Solid oxide fuel cell

ASJC Scopus subject areas

Chemistry(all)
Materials Science(all)
Condensed Matter Physics

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10.1016/j.ssi.2003.10.010

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title = "Effect of electrode microstructure on gas-phase diffusion in solid oxide fuel cells",

abstract = "The relation between electrode microstructure and gas diffusion has been investigated with different morphologies of Pt electrodes by using AC impedance techniques. The measurements were carried out at temperatures of 873-1273 K and oxygen partial pressure (PO2) of 0.01-1 atm. Gas-phase diffusion was observed only for high-performance electrodes at the high-temperature (1073-1273 K) and low-oxygen-partial-pressure regions (<0.1 atm P O2). Considering the physical and electrochemical characteristics of impedance arcs, it was found that the arc at the frequency of below 1 Hz was related to gas conversion resistance, while the arc at the frequency of around 10 Hz represented pore diffusion resistance through the current-collecting part. For a thick electrode with a low porosity, however, gas diffusion resistance through pores of an electrode was observed at a frequency of around 100 Hz. From the results of a comparison of electrode performances with different electrode microstructures, electrochemical reaction sites (ERS) are supposed to be located at the peripheral line of Pt and YSZ as well as the Pt/YSZ interfaces where reaction gas can easily diffuse.",

keywords = "Electrochemical reaction site, Electrode microstructure, Gas-phase diffusion, Impedance analysis, Solid oxide fuel cell",

author = "Yoon, {Sung Pil} and Nam, {Suk Woo} and Jonghee Han and Lim, {Tae Hoon} and Hong, {Seong Ahn} and Hyun, {Sang Hoon}",

note = "Funding Information: This work was supported by an international joint research project (2U02810) from the Ministry of Science and Technology (MOST). Copyright: Copyright 2008 Elsevier B.V., All rights reserved.",

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AU - Yoon, Sung Pil

AU - Nam, Suk Woo

AU - Han, Jonghee

AU - Lim, Tae Hoon

AU - Hong, Seong Ahn

AU - Hyun, Sang Hoon

N1 - Funding Information: This work was supported by an international joint research project (2U02810) from the Ministry of Science and Technology (MOST). Copyright: Copyright 2008 Elsevier B.V., All rights reserved.

PY - 2004/1/15

Y1 - 2004/1/15

N2 - The relation between electrode microstructure and gas diffusion has been investigated with different morphologies of Pt electrodes by using AC impedance techniques. The measurements were carried out at temperatures of 873-1273 K and oxygen partial pressure (PO2) of 0.01-1 atm. Gas-phase diffusion was observed only for high-performance electrodes at the high-temperature (1073-1273 K) and low-oxygen-partial-pressure regions (<0.1 atm P O2). Considering the physical and electrochemical characteristics of impedance arcs, it was found that the arc at the frequency of below 1 Hz was related to gas conversion resistance, while the arc at the frequency of around 10 Hz represented pore diffusion resistance through the current-collecting part. For a thick electrode with a low porosity, however, gas diffusion resistance through pores of an electrode was observed at a frequency of around 100 Hz. From the results of a comparison of electrode performances with different electrode microstructures, electrochemical reaction sites (ERS) are supposed to be located at the peripheral line of Pt and YSZ as well as the Pt/YSZ interfaces where reaction gas can easily diffuse.

AB - The relation between electrode microstructure and gas diffusion has been investigated with different morphologies of Pt electrodes by using AC impedance techniques. The measurements were carried out at temperatures of 873-1273 K and oxygen partial pressure (PO2) of 0.01-1 atm. Gas-phase diffusion was observed only for high-performance electrodes at the high-temperature (1073-1273 K) and low-oxygen-partial-pressure regions (<0.1 atm P O2). Considering the physical and electrochemical characteristics of impedance arcs, it was found that the arc at the frequency of below 1 Hz was related to gas conversion resistance, while the arc at the frequency of around 10 Hz represented pore diffusion resistance through the current-collecting part. For a thick electrode with a low porosity, however, gas diffusion resistance through pores of an electrode was observed at a frequency of around 100 Hz. From the results of a comparison of electrode performances with different electrode microstructures, electrochemical reaction sites (ERS) are supposed to be located at the peripheral line of Pt and YSZ as well as the Pt/YSZ interfaces where reaction gas can easily diffuse.

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KW - Impedance analysis

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Effect of electrode microstructure on gas-phase diffusion in solid oxide fuel cells

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