Crystals (Jun 2023)

Comparison of the Electrochemical Performances of Solid Oxide Fuel Cells with Sputtered Thin Barrier Layers Fueled by Hydrogen or Ammonia

  • Nunzia Coppola,
  • Bertrand Morel,
  • Giovanni Carapella,
  • Dario Montinaro,
  • Alice Galdi,
  • Hafiz Sami Ur Rehman,
  • Pierpaolo Polverino,
  • Cesare Pianese,
  • Julie Mougin,
  • Luigi Maritato

DOI
https://doi.org/10.3390/cryst13071040
Journal volume & issue
Vol. 13, no. 7
p. 1040

Abstract

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We investigated the influence of a fuel change from pure hydrogen to a hydrogen–ammonia mixture at different percentages on the electrochemical behavior of 50 mm in diameter Solid Oxide Fuel Cells (SOFCs) with sputtered thin buffer layers of Gd-doped ceria, varying the working temperatures from 800 °C to 650 °C. The results show that the performances of the cells are not affected by the fuel change for high working temperatures (800 °C and 750 °C). As an example, a power density value of 802 mW∙cm−2 at 1 A∙cm−2 is found when directly feeding the cell with 8 NmL∙min−1cm−2 of ammonia and with an equivalent flowrate of 12 NmL∙min−1cm−2 of H2. These power density output values are higher than those obtained in industrial state-of-art (SoA) SOFCs with screen-printed buffer layers fed with equivalent hydrogen flowrates, thanks to the improved electrochemical performances obtained in the case of cells with sputtered thin buffer layers of Gd-doped ceria. At lower working temperatures (700 °C and 650 °C), slight changes in the electrochemical behavior of the cells are observed. Nevertheless, in this temperature range, we also obtain an output current density value of 0.54 A∙cm−2 in a pure ammonia flowrate of 12 NmL min−1cm−2 at 800 mV and 700 °C, equal to the value observed in SoA button cells with industrial screen-printed GDC barrier layer fueled with 16 NmL∙min−1cm−2 of H2. These results pave the way towards the use of innovative SOFC structures with sputtered thin buffer layers fueled by ammonia.

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