168. Porous carbon for fuel cell electrodes

✍ Scribed by M.W. Reed; R.J. Brodd

• Publisher: Elsevier Science
• Year: 1964
• Tongue: English
• Weight: 137 KB
• Volume: 1
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(64)90459-2

✦ Synopsis

Electrically active impurities are known to affect the transport properties of graphite. With regard to substitutional impurities such as boron, there has been relatively little work done owing to severe difficulties in attempting to incorporate uniform and controllable amounts of boron into the graphite matrix by using conventional techniques. This situation is improving with the availability of boron alloys of pyrolytic graphite. In this paper we plan to report on systematic investigations of the heat and charge transfer characteristics of turbostratic and of graphitized deposits doped at levels of up to 1 at.'% B. Electrical, galvanomagnetic and thermoelectric data collected in the range from 4 to 1500°K will be presented and discussed; of signi~~ance are the high-tempera~re Seebeck coefficients of 1OO~V~K or more measured on specimens with boron concentrations of about 0.3%. The basal-plane thermal conductivity at temperatures below 4°K shows clear evidence of appreciable electronic contributions and points to a Lorenz number compatible with the semi-metallic band structure.