NbTi0.5Ni0.5O4 as anode compound material for SOFCs

Samir Boulfrad, Mark Cassidy, John Thomas Sirr Irvine

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

NbTi0.5Ni0.5O4 (NTNO) has been prepared using solid state synthesis and investigated as a potential anode material. The oxide form of NTNO has single phase rutile-type structure with tetragonal (P42/mnm) space group. The reduced form is a composite of nano-scaled particles of metallic Ni and Nb1.33Ti0.67O4 phase. Reduced NTNO showed high electronic conductivity up to 280 S.cm− 1 at 900 °C in reducing atmosphere, but suffers from low CTE equal to 3.78 10− 6 K− 1. Studies of NTNO as anode material were carried out in a three electrode – electrochemical half cell configuration under pure humidified H2 at 900 °C using a 2 mm thick zirconia electrolyte and without any additional current collector material. The results show a reasonable series resistance (Rs) equal to 2.7 Ωcm2 (about 50% higher than for metallic gold layers) indicating a good current collection performance for a 10 μm layer of material. The polarization resistance (Rp) was equal to 33 Ωcm2 and is attributed to a poor density of three phase boundaries (TPB) and shortage of oxide ion conduction in the anode layer. The results show the potential of NTNO as an anode material, especially after optimization of the microstructure towards the increase of TPB length.
Original languageEnglish
Pages (from-to)37-41
JournalSolid State Ionics
Volume197
Issue number1
DOIs
Publication statusPublished - 2011

Keywords

  • SOFC
  • Anode
  • NbTi0.5Ni0.5O4
  • Reduction–oxidation
  • Electronic conductivity
  • Impedance spectroscopy

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