The reaction process of hydrogen absorption and desorption on the nanocomposite of hydrogenated graphite and lithium hydride.
The lithium-carbon-hydrogen (Li-C-H) system is composed of hydrogenated nanostructural graphite (C(nano)Hx) and lithium hydride (LiH). C(nano)Hx is synthesized by ball-milling of graphite under a hydrogen atmosphere. In this work, the reaction process of hydrogen absorption and desorption on the Li-C-H system is investigated. The C(nano)Hx-LiH composite can desorb about 5.0 mass% of hydrogen at 350 degrees C with the formation of Li2C2 until the second cycle. However, the hydrogen desorption amount significantly decreases from the third cycle. Furthermore, it is shown by using gas chromatography that a considerable amount of hydrocarbons is desorbed during the rehydrogenation process. These results indicate that the amount of reaction between the polarized C-H groups in C(nano)Hx and LiH is reduced due to a decrease in the C-H groups by losing carbon atoms under the hydrogen absorption and desorption cycles.
Institute for Advanced Materials Research, Hiroshima University, 1-3-1Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530, Japan.
Hiroki
H
Miyaoka
Takayuki
T
Ichikawa
Yoshitsugu
Y
Kojima
D000327:Adsorption; D003460:Crystallization / Q000379:methods*; D006108:Graphite / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry* / Q000302:isolation & purification; D008094:Lithium / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013499:Surface Properties
D046911:Macromolecular Substances; D006108:Graphite; D006859:Hydrogen; D008094:Lithium