Variation of the Seebeck coefficient with hydrogen content in carbon microfilaments

• Published in: Journal of materials science. Materials in electronics 2012-08, Vol.23 (8), p.1470-1476
• Main Authors: Madroñero, A., Robla, J., García-Hierro, J., Martín-González, M. S., Díaz, P., López, A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemical and electrochemical properties; Chemistry and Materials Science; Condensed matter: structure, mechanical and thermal properties; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Materials and auxiliary equipments used in energy engineering; Materials Science; Metals. Metallurgy; Optical and Electronic Materials; Physics; Solid surfaces and solid-solid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-011-0613-5

The Seebeck coefficient of vapour grown carbon fibres and carbon fibres made from polyacryolytrile precursor has been studied as a possible parameter to control hydrogen storage inside. The sign of the Seebeck coefficient gives the sign of the dominant charge carriers in the fibres, and when hydrogen is absorbed by the carbonaceous material, mainly as H + , it acts as a positive charge carrier. A simple two-band electronic model has been considered to explain the influence of hydrogenation on the Seebeck’s coefficient of these carbon microfibres. The most favourable condition for hydrogen adsorption is a moderately low pressure of hydrogen. Furthermore, it was observed that outgassing is more pronounced than expected in some types of fibres, thereby supporting the proposed presence of hydrogen generated during the manufacturing process.