ABSTRACT

Solid oxide fuel cell (SOFC) is an all-solid electrochemical device that can convert chemical energy into electric energy via electrochemical oxidation of fuels. As shown in Figure 13.1, SOFC is composed of a solid oxide electrolyte (fast ionic conductor) and attached anode and cathode on its two sides to form a sandwich structure named positive electrode-electrolytenegative electrode (PEN) assembly. On the anode, fuel is electrochemically oxidized and provides electrons to the external circuit. While on the cathode, oxygen gas is adsorbed and electrochemically reduced to oxygen ion by gaining the electrons transported from the external circuit. In an electrolyte with oxygen-ion conduction, oxygen ions diffuse through the electrolyte from cathode to anode. In a typical SOFC, both the

electrolyte and cathode are oxide ceramic materials, although the anode is a porous cermet (such as Ni-YSZ) under operation condition after reduction, the as-prepared anode usually is in oxide ceramic status (e.g., NiO-YSZ composite).