1. Introduction
A solid oxide fuel cell (SOFC) is an energy conversion device that produces electricity by electrochemically combining a fuel and an oxidant across an ionic conducting oxide electrolyte. The dense electrolyte is sandwiched between two porous electrodes, the anode and the cathode (the anode/electrolyte/cathode sandwich is referred to as a single cell). Fuel is fed to the anode, undergoes an oxidation reaction, and releases electrons to the external circuit. Oxidant is fed to the cathode, accepts electrons from the external circuit, and undergoes a reduction reaction. The electron flow in the external circuit from the anode to the cathode produces direct-current electricity. In an SOFC stack, single cells are connected in electrical series via a component called the interconnect.
At present, the most common materials for the SOFC are oxide ion conducting yttria-stabilized zirconia (YSZ) for the electrolyte, strontium-doped lanthanum manganite (LSM) for the cathode, nickel/YSZ for the anode, and doped lanthanum chromite or high-temperature metals for the interconnect. The SOFC operates at about 700 to 1000 °C under atmospheric or pressurized conditions depending on specific cell configurations and system designs. In the past 10 years, the SOFC has received much attention and development effort in this area has expanded significantly [1], [2], [3] and [4]. The attractiveness of SOFC technology is its efficient generation of electricity from a variety of fuels for a wide range of power generation applications. This paper discusses and summarizes the SOFC's features and provides an overview of this technology's potential applications.