▎ 摘　　要

NOVELTY - A carbon fiber has truncated conical tubular graphene layers which include hexagonal carbon layers (10). Each graphene layer has large and small ring ends along axial direction. The large ends of the graphene layers are linked by layer links including pentagonal carbon layers such that the entire outer surface is closed, to obtain multi-semiring structure. USE - For electrode material (claimed) e.g. anode material, used in batteries such as lithium-ion secondary battery. Also, for field electron emitter. ADVANTAGE - Large amount of lithium ions are easily absorbed on the edges of the hexagonal carbon layers of the carbon fiber. Thus, storage capacity of the battery is increased. Since the edges are irregular, intercalation of ions between the hexagonal carbon layers is obstructed. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) electrode material which includes carbon fiber; and (2) carbon fiber manufacturing method which involves heating the carbon fiber in non-oxidizing atmosphere and linking the large ring ends of the hexagonal carbon layers by large links. The carbon fiber outer surface is closed to obtain multi-semiring structure. The carbon fiber is then heated in an oxidizing atmosphere and the large links are released, such that hexagonal carbon layers are exposed at the large ring ends. DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of the carbon fiber. hexagonal carbon layers (10)