Abstract: A fluorinated carbon fiber has a hollow core structure in which a number of hexagonal carbon layers in the shape of a cup having no bottom are stacked. Edges of the hexagonal carbon layers are exposed on the inner and outer surfaces of the fluorinated carbon fiber. In the fluorinated carbon fiber, the exposed edges of the hexagonal carbon layers are fluorinated and have a structure shown by CxFy.

Abstract: An electrode material for an electric double layer capacitor having a carbon fiber as an essential material. The carbon fiber has a coaxial stacking morphology of truncated conical tubular graphene layers, and each of the truncated conical tubular graphene layers includes a hexagonal carbon layer. Edges of the hexagonal carbon layer are exposed. The exposed edges of the hexagonal carbon layers have a high degree of activity and can be modified with functional groups such as —COOH, —CHO, or —OH. This enables use of the carbon fiber as the electrode material. The specific surface area of the surfaces on which the edges are exposed is extremely large, whereby a large-capacitance electric double layer capacitor can be formed.