Performance and sulfur tolerance of a short stack with solid oxide cells using infiltrated strontium titanate based anodes

Christensen, Jens Ole; Longo, Giulia; Bausinger, Holger; Mai, Andreas; Sudireddy, Bhaskar Reddy; Hagen, Anke

doi:10.1016/j.jpowsour.2023.233458

Cited by 4 publications

(1 citation statement)

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“…Oxide phases derived from perovskite-type SrTiO 3 and SrVO 3 are considered potential alternatives to traditional Ni-YSZ (yttria-stabilized zirconia) anode materials used in hydrocarbon-fueled solid oxide fuel cells (SOFCs) [1][2][3][4][5][6]. Apart from issues related to redox instability and microstructural degradation due to the agglomeration of nickel particles with time [7,8], Ni-YSZ cermets suffer from coking and poisoning by ppm levels of H 2 S contaminant in fuels such as natural gas or biogas [1,9].…”

Section: Introductionmentioning

confidence: 99%

SrTiO3-SrVO3 Ceramics for Solid Oxide Fuel Cell Anodes: A Route from Oxidized Precursors

Macías,

Frade,

Yaremchenko

2023

Materials

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Perovskite-type Sr(Ti,V)O3-δ ceramics are promising anode materials for natural gas- and biogas-fueled solid oxide fuel cells, but the instability of these phases under oxidizing conditions complicates their practical application. The present work explores approaches to the fabrication of strontium titanate-vanadate electrodes from oxidized precursors. Porous ceramics with the nominal composition SrTi1−yVyOz (y = 0.1–0.3) were prepared in air via a solid state reaction route. Thermal processing at temperatures not exceeding 1100 °C yielded composite ceramics comprising perovskite-type SrTiO3, pyrovanadate Sr2V2O7 and orthovanadate Sr3(VO4)2 phases, while increasing firing temperatures to 1250–1440 °C enabled the formation of SrTi1−yVyO3 perovskites. Vanadium was found to substitute into the titanium sublattice predominantly as V4+, even under oxidizing conditions at elevated temperatures. Both perovskite and composite oxidized ceramics exhibit moderate thermal expansion coefficients in air, 11.1–12.1 ppm/K at 30–1000 °C, and insignificant dimensional changes induced by reduction in a 10%H2-N2 atmosphere. The electrical conductivity of reduced perovskite samples remains comparatively low, ~10−1 S/cm at 900 °C, whereas the transformation of oxidized vanadate phases into high-conducting SrVO3−δ perovskites upon reduction results in enhancement in conductivity, which reaches ~3 S/cm at 900 °C in porous composite ceramics with nominal composition SrTi0.7V0.3Oz. The electrical performance of the composite is expected to be further improved by optimization of the processing route and microstructure to facilitate the reduction of the oxidized precursor and attain better percolation of the SrVO3 phase.

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