Electrical conductivity of Ni-YSZ composites: Degradation due to Ni particle growth

Mikko Pihlatie (Corresponding Author), A. Kaiser, M. Mogensen, M. Chen

    Research output: Contribution to journalArticleScientificpeer-review

    69 Citations (Scopus)

    Abstract

    The short-term changes in the electrical conductivity of Ni–YSZ composites (cermets) suitable for use in Solid Oxide Fuel Cells (SOFC) were measured by an in-situ 4-point DC technique. The isothermal reduction was carried out in dry, humidified or wet hydrogen at temperatures from 600 to 1000 °C. While the cermets reduced at 600 °C showed a stable conductivity of 1000–1200 S/cm, rapid initial conductivity loss was observed at elevated temperatures. At 1000 °C the conductivity degraded nearly instantaneously to about 800 S/cm, and continued to decline fast to about 400 S/cm. At 850 °C, the presence of steam did have an accelerating effect on the conductivity loss. Scanning Electron Microscopy of cermets reduced in different conditions showed increasing particle size and loss of metal-to-metal percolation in the samples reduced at higher temperatures. The short-term changes in conductivity were modelled using two different semi-empirical approaches. Thermodynamic calculations were carried out to assess the vaporisation of Ni in the conditions tested. The rate and mechanisms of conductivity degradation due to Ni particle growth are discussed in light of the measurements, modelling and literature data.
    Original languageEnglish
    Pages (from-to)82-90
    Number of pages9
    JournalSolid State Ionics
    Volume189
    Issue number1
    DOIs
    Publication statusPublished - 2011
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Cermets
    yttria-stabilized zirconia
    degradation
    cermets
    Degradation
    conductivity
    electrical resistivity
    composite materials
    Composite materials
    Metals
    Steam
    Solid oxide fuel cells (SOFC)
    Vaporization
    Temperature
    Hydrogen
    Particle size
    Thermodynamics
    Scanning electron microscopy
    solid oxide fuel cells
    steam

    Keywords

    • SOFC
    • Ni-YSZ
    • Ni particle growth
    • Ostwald ripening
    • Electrical conductivity
    • Degradation

    Cite this

    Pihlatie, Mikko ; Kaiser, A. ; Mogensen, M. ; Chen, M. / Electrical conductivity of Ni-YSZ composites : Degradation due to Ni particle growth. In: Solid State Ionics. 2011 ; Vol. 189, No. 1. pp. 82-90.
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    abstract = "The short-term changes in the electrical conductivity of Ni–YSZ composites (cermets) suitable for use in Solid Oxide Fuel Cells (SOFC) were measured by an in-situ 4-point DC technique. The isothermal reduction was carried out in dry, humidified or wet hydrogen at temperatures from 600 to 1000 °C. While the cermets reduced at 600 °C showed a stable conductivity of 1000–1200 S/cm, rapid initial conductivity loss was observed at elevated temperatures. At 1000 °C the conductivity degraded nearly instantaneously to about 800 S/cm, and continued to decline fast to about 400 S/cm. At 850 °C, the presence of steam did have an accelerating effect on the conductivity loss. Scanning Electron Microscopy of cermets reduced in different conditions showed increasing particle size and loss of metal-to-metal percolation in the samples reduced at higher temperatures. The short-term changes in conductivity were modelled using two different semi-empirical approaches. Thermodynamic calculations were carried out to assess the vaporisation of Ni in the conditions tested. The rate and mechanisms of conductivity degradation due to Ni particle growth are discussed in light of the measurements, modelling and literature data.",
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    Electrical conductivity of Ni-YSZ composites : Degradation due to Ni particle growth. / Pihlatie, Mikko (Corresponding Author); Kaiser, A.; Mogensen, M.; Chen, M.

    In: Solid State Ionics, Vol. 189, No. 1, 2011, p. 82-90.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Electrical conductivity of Ni-YSZ composites

    T2 - Degradation due to Ni particle growth

    AU - Pihlatie, Mikko

    AU - Kaiser, A.

    AU - Mogensen, M.

    AU - Chen, M.

    PY - 2011

    Y1 - 2011

    N2 - The short-term changes in the electrical conductivity of Ni–YSZ composites (cermets) suitable for use in Solid Oxide Fuel Cells (SOFC) were measured by an in-situ 4-point DC technique. The isothermal reduction was carried out in dry, humidified or wet hydrogen at temperatures from 600 to 1000 °C. While the cermets reduced at 600 °C showed a stable conductivity of 1000–1200 S/cm, rapid initial conductivity loss was observed at elevated temperatures. At 1000 °C the conductivity degraded nearly instantaneously to about 800 S/cm, and continued to decline fast to about 400 S/cm. At 850 °C, the presence of steam did have an accelerating effect on the conductivity loss. Scanning Electron Microscopy of cermets reduced in different conditions showed increasing particle size and loss of metal-to-metal percolation in the samples reduced at higher temperatures. The short-term changes in conductivity were modelled using two different semi-empirical approaches. Thermodynamic calculations were carried out to assess the vaporisation of Ni in the conditions tested. The rate and mechanisms of conductivity degradation due to Ni particle growth are discussed in light of the measurements, modelling and literature data.

    AB - The short-term changes in the electrical conductivity of Ni–YSZ composites (cermets) suitable for use in Solid Oxide Fuel Cells (SOFC) were measured by an in-situ 4-point DC technique. The isothermal reduction was carried out in dry, humidified or wet hydrogen at temperatures from 600 to 1000 °C. While the cermets reduced at 600 °C showed a stable conductivity of 1000–1200 S/cm, rapid initial conductivity loss was observed at elevated temperatures. At 1000 °C the conductivity degraded nearly instantaneously to about 800 S/cm, and continued to decline fast to about 400 S/cm. At 850 °C, the presence of steam did have an accelerating effect on the conductivity loss. Scanning Electron Microscopy of cermets reduced in different conditions showed increasing particle size and loss of metal-to-metal percolation in the samples reduced at higher temperatures. The short-term changes in conductivity were modelled using two different semi-empirical approaches. Thermodynamic calculations were carried out to assess the vaporisation of Ni in the conditions tested. The rate and mechanisms of conductivity degradation due to Ni particle growth are discussed in light of the measurements, modelling and literature data.

    KW - SOFC

    KW - Ni-YSZ

    KW - Ni particle growth

    KW - Ostwald ripening

    KW - Electrical conductivity

    KW - Degradation

    U2 - 10.1016/j.ssi.2011.02.001

    DO - 10.1016/j.ssi.2011.02.001

    M3 - Article

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    JO - Solid State Ionics

    JF - Solid State Ionics

    SN - 0167-2738

    IS - 1

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