Structure of functional graphite as hydrogen storage and cell materials

Abstract

Mechanical alloying was employed to synthesize hydrogen storage graphite materials and cell materials as anodes of secondary lithium-ion batteries. First of all, the mechanical alloying of graphite was carried out under Ar gas atmosphere. Hexagonal graphite was used as a starting material. The transformation from the hexagonal graphite composed of layers into amorphous-like carbon was observed by using a highly resolved neutron diffraction technique. In case of the mechanical alloying under D₂ gas atmosphere, deuterium was absorbed by the solid-gas reaction. Two types of the location of deuterium atoms were found in RDF(r). One is the C-D covalent bond and the other is due to deuterium located between layers of the graphite. Lithium-graphite intercalation compound was obtained by mechanical alloying of graphite and lithium mixed powders. The short range structure around a Li atom was observed by using the advantage of neutron diffraction. The coordination number of the C-Li correlation indicates the formation of LiC_3.1 intercalation compound.