Effect of tungsten doping on strontium ferrite electrode for symmetrical solid oxide electrochemical cell

Taolong Su, Yihang Li, Yi Yang, Zheqiang Xu, Nai Shi, Yanhong Wan, Yun Xie, Daoming Huan, Shuangshuang Xue, Changrong Xia

Research output: Contribution to journalArticlepeer-review

Abstract

Tungsten-doped strontium ferrite (SrFe1-xWxO3-δ, SFW) is prepared and characterized as the electrode materials for symmetrical solid oxide electrochemical cell. X-ray diffraction refinement reveals the symmetrical structure transform from cubic (pm3¯m) for x = 0.1 to tetragonal (I4/m) when x = 0.2. According to the analysis including electrical conductivity, Hydrogen temperature-programmed reduction (H2-TPR), thermal expansion and X-ray photoelectron spectra (XPS), it suggests that the decrease in conductivity, content of Fe2+ and oxygen vacancy concentration with the increase of W content is attributed to the stronger lattice framework. The oxygen vacancy can be dramatically activated around 600 °C. Using SrFe0.8W0.2O3-δ as the electrodes, symmetrical single cells supported on doped ceria electrolytes can achieve acceptable power density (0.19 W cm−2 at 750 °C) and considerable stability. Meanwhile symmetrical cells with La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) electrolyte substrates can achieve 0.75 A cm−2 at 800 °C under the voltage of OCV (open circuit voltage) +0.5 V when it is operated in electrolysis mode. SrFe0.8W0.2O3-δ can gain a considerable stability and electrochemical activity under both oxide and reductive atmospheres. Oxygen vacancy formation energy (Evac) and electron density distribution are computed to verify the enhancement on crystal structure stability by doping W. The Evac critically depends on the distance from the W atom.

Original languageEnglish
Pages (from-to)23401-23410
Number of pages10
JournalInternational Journal of Hydrogen Energy
Volume45
Issue number43
DOIs
Publication statusPublished - Sep 3 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology

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