Abstract: Disclosed is a process for preparing milled graphite fibers in which the amount of metallic components contained in the milled carbon fibers before graphitizing is limited to not more than 100/1,000,000 in terms of a ratio by weight. Also disclosed is a process for preparing milled graphite fibers in which the amount of metallic components contained in the milled carbon fibers before graphitizing except metallic components originally contained in the fibers themselves is limited to not more than 50/1,000,000 in terms of a ratio by weight. According to these processes, there can be obtained milled graphite fibers whose surfaces are inert, which suffer few longitudinal crackings and which are almost free from occurrence of particulate substances comprising agglomerated or bonded fibers.

Abstract: A negative electrode for use in a secondary battery which comprises milled graphite fibers derived from mesophase pitch each having circumferential, upper end and lower end faces, the milled graphite fibers each being composed of graphite layers having therebetween voids as inlets and outlets for lithium ions, all of the circumferential, upper end and lower end faces having openings of the voids between the graphite layers, which serve as inlets or outlets for lithium ions. This negative electrode for use in a secondary battery can be utilized to provide a lithium secondary battery of nonaqueous electrolyte which has large charge and discharge capacities and which permits setting the current density at charge or discharge high.

Abstract: There are here disclosed carbon fibers for reinforcement of cement which are obtained by applying, onto the surfaces of carbon fibers, esters of oleic acid and aliphatic monovalent alcohols, esters of oleyl alcohol and monovalent fatty acids, polyoxyalkylene bisphenol ethers or polyether esters as sizing agents, and a cement composite material having a bending strength of 300 kgf/cm.sup.2 or more which contains cut carbon fibers having a fiber length of 10 to 50 mm at a mixing volume ratio of the cut carbon fibers to the cement matrix in the range of 1 to 5%. According to the present invention, there are provided the carbon fibers for reinforcement of cement which have excellent adhesive properties to the cement, good process passage properties through a direct spray gun and good bundling properties and which are suitable for a direct spray method, and the cement composite material using the carbon fibers and having high bending strength.