Positive electrode forming material, component thereof, method for producing the same and rechargeable lithium-ion battery

A slurry or a paste for a positive electrode forming material used in forming a network coating on a particle surface of a positive electrode active material, said slurry or paste comprising:

• a dispersion;
• a binder;
• and
• the positive electrode active material, wherein
• the dispersion is prepared by dispersing fine carbon fibers with surfaces hydrophilized by oxidization in one or more dispersing solvents selected from a group consisting of a solvent and water,
• the positive electrode active material consists of fine particles having an average particle diameter of 0.03 to 40 μm,
• the dispersion includes the fine carbon fibers and the dispersive agent, where each of the fine carbon fibers is a carbon nanofiber having an average fiber diameter of 1 to 100 nm and an aspect ratio of 5 or greater, and
• a lamination interval of (002) face of graphite layers of the carbon nanofiber is 0.35 nm or less.

A method for preparing a dispersion for a positive electrode forming material, the method comprising the steps of:

• adding sulfur-containing strong acid to fine carbon fibers to form an acid suspension;
• adding nitric acid to the acid suspension of fine carbon fibers to form a slurry;
• agitating the slurry under heat and thereby hydrophilizing a surface of the fine carbon fibers by oxidization;
• collecting the fine carbon fibers by filtering separation;
• and
• mixing the fine carbon fibers with a dispersion medium, wherein
• each of the fine carbon fibers is a carbon nanofiber having an average fiber diameter of 1 to 100 nm and an aspect ratio of 5 or greate, and
• a lamination interval of (002) face of graphite layers of the carbon nanofiber is 0.35 nm or less.