Ni/YSZ electrodes structures optimized for increased electrolysis performance and durability

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Abstract

Cermet Ni/YSZ electrodes are the most commonly applied fuel electrode for solid oxide cells (SOC) both when targeting solid oxide fuel cell (SOFC) applications and when used as solid oxide electrolysis cell (SOEC). In this work we report on the correlation between initial Ni/YSZ microstructure and the resulting electrochemical performance both initially and during long-term electrolysis testing at high current density and high p(H2O) inlet. Especially, this work focuses on microstructure optimization to hinder Ni mobility and migration during long-term operation and illustrates the key-role of electrode over-potential on the degradation of the Ni/YSZ electrodes in SOEC. We find that for long-term stability for electrolysis at high current densities and high p(H2O) the as-produced NiO/YSZ precursor electrode should be: 1) As dense as possible, 2) as fine particle and pore sized as possible and 3) the three phases (Ni, YSZ and pore phase) shall be size-matched and well-dispersed. Applying such microstructure optimized Ni/YSZ electrode we show SOEC test results with long-term degradation rate as low as 0.3-0.4%/kh at - 1 A/cm2, 800 °C and inlet gas mixture of p(H2O)/p(H2):90/10. This enables SOEC operation of such cell for more than 5 years below thermo-neutral potential at these operating conditions.
Original languageEnglish
JournalSolid State Ionics
Volume293
Pages (from-to)27-36
Number of pages10
ISSN0167-2738
DOIs
Publication statusPublished - 2016

Keywords

  • Solid oxide electrolysis cells
  • Ni/YSZ electrode
  • Microstructure
  • Electrochemical impedance spectroscopy
  • Performance
  • Durability

Cite this

@article{517aff0067334e1b913ca84b87e0e2b0,
title = "Ni/YSZ electrodes structures optimized for increased electrolysis performance and durability",
abstract = "Cermet Ni/YSZ electrodes are the most commonly applied fuel electrode for solid oxide cells (SOC) both when targeting solid oxide fuel cell (SOFC) applications and when used as solid oxide electrolysis cell (SOEC). In this work we report on the correlation between initial Ni/YSZ microstructure and the resulting electrochemical performance both initially and during long-term electrolysis testing at high current density and high p(H2O) inlet. Especially, this work focuses on microstructure optimization to hinder Ni mobility and migration during long-term operation and illustrates the key-role of electrode over-potential on the degradation of the Ni/YSZ electrodes in SOEC. We find that for long-term stability for electrolysis at high current densities and high p(H2O) the as-produced NiO/YSZ precursor electrode should be: 1) As dense as possible, 2) as fine particle and pore sized as possible and 3) the three phases (Ni, YSZ and pore phase) shall be size-matched and well-dispersed. Applying such microstructure optimized Ni/YSZ electrode we show SOEC test results with long-term degradation rate as low as 0.3-0.4{\%}/kh at - 1 A/cm2, 800 °C and inlet gas mixture of p(H2O)/p(H2):90/10. This enables SOEC operation of such cell for more than 5 years below thermo-neutral potential at these operating conditions.",
keywords = "Solid oxide electrolysis cells, Ni/YSZ electrode, Microstructure, Electrochemical impedance spectroscopy, Performance, Durability",
author = "Anne Hauch and Karen Brodersen and Ming Chen and Mogensen, {Mogens Bjerg}",
year = "2016",
doi = "10.1016/j.ssi.2016.06.003",
language = "English",
volume = "293",
pages = "27--36",
journal = "Solid State Ionics",
issn = "0167-2738",
publisher = "Elsevier",

}

Ni/YSZ electrodes structures optimized for increased electrolysis performance and durability. / Hauch, Anne; Brodersen, Karen; Chen, Ming; Mogensen, Mogens Bjerg.

In: Solid State Ionics, Vol. 293, 2016, p. 27-36.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Ni/YSZ electrodes structures optimized for increased electrolysis performance and durability

AU - Hauch, Anne

AU - Brodersen, Karen

AU - Chen, Ming

AU - Mogensen, Mogens Bjerg

PY - 2016

Y1 - 2016

N2 - Cermet Ni/YSZ electrodes are the most commonly applied fuel electrode for solid oxide cells (SOC) both when targeting solid oxide fuel cell (SOFC) applications and when used as solid oxide electrolysis cell (SOEC). In this work we report on the correlation between initial Ni/YSZ microstructure and the resulting electrochemical performance both initially and during long-term electrolysis testing at high current density and high p(H2O) inlet. Especially, this work focuses on microstructure optimization to hinder Ni mobility and migration during long-term operation and illustrates the key-role of electrode over-potential on the degradation of the Ni/YSZ electrodes in SOEC. We find that for long-term stability for electrolysis at high current densities and high p(H2O) the as-produced NiO/YSZ precursor electrode should be: 1) As dense as possible, 2) as fine particle and pore sized as possible and 3) the three phases (Ni, YSZ and pore phase) shall be size-matched and well-dispersed. Applying such microstructure optimized Ni/YSZ electrode we show SOEC test results with long-term degradation rate as low as 0.3-0.4%/kh at - 1 A/cm2, 800 °C and inlet gas mixture of p(H2O)/p(H2):90/10. This enables SOEC operation of such cell for more than 5 years below thermo-neutral potential at these operating conditions.

AB - Cermet Ni/YSZ electrodes are the most commonly applied fuel electrode for solid oxide cells (SOC) both when targeting solid oxide fuel cell (SOFC) applications and when used as solid oxide electrolysis cell (SOEC). In this work we report on the correlation between initial Ni/YSZ microstructure and the resulting electrochemical performance both initially and during long-term electrolysis testing at high current density and high p(H2O) inlet. Especially, this work focuses on microstructure optimization to hinder Ni mobility and migration during long-term operation and illustrates the key-role of electrode over-potential on the degradation of the Ni/YSZ electrodes in SOEC. We find that for long-term stability for electrolysis at high current densities and high p(H2O) the as-produced NiO/YSZ precursor electrode should be: 1) As dense as possible, 2) as fine particle and pore sized as possible and 3) the three phases (Ni, YSZ and pore phase) shall be size-matched and well-dispersed. Applying such microstructure optimized Ni/YSZ electrode we show SOEC test results with long-term degradation rate as low as 0.3-0.4%/kh at - 1 A/cm2, 800 °C and inlet gas mixture of p(H2O)/p(H2):90/10. This enables SOEC operation of such cell for more than 5 years below thermo-neutral potential at these operating conditions.

KW - Solid oxide electrolysis cells

KW - Ni/YSZ electrode

KW - Microstructure

KW - Electrochemical impedance spectroscopy

KW - Performance

KW - Durability

U2 - 10.1016/j.ssi.2016.06.003

DO - 10.1016/j.ssi.2016.06.003

M3 - Journal article

VL - 293

SP - 27

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JO - Solid State Ionics

JF - Solid State Ionics

SN - 0167-2738

ER -