Recycling and characterization of end-of-life solid oxide fuel/electrolyzer ceramic material cell components

Abstract

In this work, a strategy for recycling and recovery of anode supported Solid Oxide Fuel Cell (SOFC) ceramic components is presented. From commercial cells, electrodes and electrolyte are separated by mechanical scraping and grinding, followed by thermal and chemical treatments. Air electrode (LaxSr1-xCoO3), nickel oxide (NiO), which accounts for about 50% of the cell weight, and yttria-stabilized zirconia (YSZ), which is coming from both the fuel electrode and the electrolyte, were successfully separated, and 90–92% of the total weight of initial Ni and YSZ can be collected. The recovered materials are characterized by X-ray diffraction, scanning electron microscopy, (thermal, chemical) analysis and BET surface area measurement, and impurities amounts never excess 1 At.%. The conductivity level of the recycled YSZ materials was measured in air by electrochemical impedance spectroscopy and is found comparable with commercial YSZ material, with a total value exceeding 6.4 10−3 S cm−1 at 700 °C. The contributions of grain and grain boundary conductivities to the total conductivity are clearly distinguishable at lower temperatures.