SYNTHESIS OF YSZ BY ARC-MELTING AS A SOLID OXIDE FUEL CELL ELECTROLYTE

The current research deals with the conversion of chemical energy into electricity. The conversion system is a solid oxide fuel cell (SOFC), which today shows a conversion efficiency in the order of 60%. The system is based on a solid electrolyte of dense yttria stabilized zirconia (YSZ), enabling an effective O^- ionic conduction in the temperatures range of 600-1000^oC.

8YSZ is a ZrO₂ matrix doped by 8at% of Y₂O₃ which stabilizes a cubic structure, it is a well establish composition for SOFC electrolytes due to an excellent ionic conductivity. Today, the YSZ is commonly synthesized by chemical approaches. Here, we present a unique synthesis approach using arc-melting furnace for obtaining cubic 8YSZ, as was confirmed by X-ray diffraction (XRD) results.

A metallurgical route for production of dense 8YSZ electrolyte is proposed: synthesis of 8YSZ from stoichiometric amount of pure ZrO₂ and Y₂O₃ using arc-melting furnace, following grinding in an energetic planetary ball-milling system into a powder and finally compaction using spark plasma sintering (SPS) or hot pressing.

The proposed synthesis route enables a unique possibility of controlling the phase structure of YSZ, while optimizing the mechanical and electrochemical properties.