Abstract: The purpose of the present invention is to provide a carbon black capable of efficiently covering the surface of an electrode active material and enhancing the electric current collection effect as an electroconductive agent of a secondary cell. A carbon black comprising carbon black aggregates (2) in which the ratio PPA/d of the number of primary particles (1) (PPA) and the diameter d (nm) of the primary particles (1) is 8 or higher.

Abstract: The purpose of the present invention is to provide a carbon black capable of efficiently covering the surface of an electrode active material and enhancing the electric current collection effect as an electroconductive agent of a secondary cell. A carbon black comprising carbon black aggregates (2) in which the ratio PPA/d of the number of primary particles (1) (PPA) and the diameter d (nm) of the primary particles (1) is 8 or higher.

Abstract: In the present invention, a starting material liquid including a carbon compound and a catalyst or a catalyst precursor, and a reaction vessel having a high-temperature zone heated to 900-1,300° C. are prepared. The starting material liquid is introduced into the reaction vessel, and a mixture is generated which comprises a gas including a carbon source, and catalyst microparticles dispersed in the gas. A carrier gas is then introduced in pulses into the reaction vessel, and the mixture is pushed out to the high-temperature zone. The carbon source and catalyst microparticles included in the mixture are then brought into contact with each other in the high-temperature zone, initial fibers are grown, and carbon fibers are subsequently grown in an environment in which the carrier gas is retained.

Abstract: In the present invention, a starting material liquid including a carbon compound and a catalyst or a catalyst precursor, and a reaction vessel having a high-temperature zone heated to 900-1,300° C. are prepared. The starting material liquid is introduced into the reaction vessel, and a mixture is generated which comprises a gas including a carbon source, and catalyst microparticles dispersed in the gas. A carrier gas is then introduced in pulses into the reaction vessel, and the mixture is pushed out to the high-temperature zone. The carbon source and catalyst microparticles included in the mixture are then brought into contact with each other in the high-temperature zone, initial fibers are grown, and carbon fibers are subsequently grown in an environment in which the carrier gas is retained.