Electrical properties of carbons—resistance of powder materials

✍ Scribed by Aida Espinola; Pablo Mourente Miguel; Milton Roedel Salles; Ailton Ribeiro Pinto

• Publisher: Elsevier Science
• Year: 1986
• Tongue: English
• Weight: 474 KB
• Volume: 24
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(86)90235-6

✦ Synopsis

AL&r&-A significant property in the selection of materials for the manufacture of porous carbon electrodes is the electrical resistivity. The problem of determining this property in porous materials is scarcely treated in the literature. The authors studied a large number of Brazilian carbonaceous materials, having in view the construction of gas diffusion electrodes for fuel cells. An apparatus was designed, with the same idea of a sample cell under pressure, as the one by Brodd and Kosawa in 197R; the fundamental modifications introduced resulted in considerable improvement in precision. A detailed design of the apparatus and the electrical circuit used are presented. It is evident from the curves that carbons are ohmic resistors and that a strong dependence exists between resistivity and pressure, such that only at fixed and constant pressures a comparison of the resistivity values is meaningful.

Gas diffusion electrodes were manufactured with a composite prepared from a paste of the carbonaceous material. An elec~g~phite, a petroleum coke and an acetylene black exhibited excellent electrical properties as electrode materials.