This paper describes the basic properties demanded and the manufacturing technology of electrode substrate used in phosphoric acid fuel cell. Because of low cost, acceptable properties and durability, only all carbon electrode substrates that are treated at over 2000°C temperature are practical.
The electrode substrate has been improved in;
·diffusibility to achieve higher electrical current density.
·electrical conductivity to reduce ohmic loss.
·thermal conductivity to remove heat generated in cells, smoothly.
·mechanical properties to reduce handling loss.
·chemical stability under operating condition at cathodic potential in hot phosphoric acid.
Several carbon electrode substrates have been developed for phosphoric acid fuel cell. A carbon paper electrode is made from carbon fibers and a resin through conventional paper manufacturing. A molded electrode is made from short carbon fibers, a binder resin and other material to make micro pores in it after baking. An integrated electrode that consists of a carbon separator and a pair of ribbed electrode substrate (mold type) has been developed to reduce electrical and thermal resistance, and to im-prove mechanical properties.
