Development of Medium-Temperature Solid Oxide Fuel Cell Materials and Single Cells in Estonia

Abstract

Estonian solid oxide fuel cell program started in 2001. Solid oxide fuel cell single cells based on Ni-Ce0.9Gd0.1O2-δ or Ni-Zr0.92Y0.08O2-δ supporting anodes, bi-layered Zr0.92Y0.08O2-δ | Ce0.9Gd0.1O2-δ or Zr0.9Sc0.1O2-δ | Ce0.9Gd0.1O2-δ electrolytes and micro-meso-porous La0.6Sr0.4CoO3-δ, Gd0.6Sr0.4CoO3-δ or Pr0.6Sr0.4CoO3-δ cathodes prepared from nano/microporous powders at different sintering temperatures and pore former additions in the raw cathode and anode pastes have been studied. Different physical (XRD, high-temperature XRD under electrochemical working conditions, FIB-SEM, AFM, and BET) and electrochemical (cyclic voltammetry, chronoamperometry and electrochemical impedance) methods have been applied. Influence of the anode and cathode porosity, depending on the electrode preparation methods, and also of the bi-layered electrolyte properties (chemical composition, thickness, etc.) on the power density of the single cells has been shown and discussed. During last two years the synchrotron radiation based X-ray absorption spectroscopy under electrochemical polarization, gas feeding and temperature cycling conditions has been applied for analysis of anode surface composition.