| 摘要 |
PROBLEM TO BE SOLVED: To provide a cathode material capable of achieving a high electron- emitting density and an electron-emitting properties in a low electric field, and further to provide an electron-emitting source having the material, a method for producing the electron-emitting source, a display element having the electron- emitting source and a lithium ion secondary battery obtained by using the carbonaceous material as an activate material for a cathode. SOLUTION: This graphite nanofiber material has a columnar structure obtained by laminating graphene sheets having truncated ice cream cone shapes through a catalytic metal, or a structure obtained by stacking small fragments of the graphene sheets having shapes along the surface shape of the catalytic metal through the catalytic metal. The catalytic metal is composed of Fe, Co or an alloy containing at least one kind of these metals. The electron-emitting source, the display element constituted so that a desired part of a light emitter may emit the light, the carbonaceous material for the cathode of the battery, and the lithium ion secondary battery are obtained by utilizing the material. |
