Abstract: A calcined two-layer carbon material is prepared characterized in that edge parts of a core carbon material are particularly or entirely coated with a coat-forming carbon material and that the carbon material is nearly spherical or ellipsoidal, wherein the carbon material has a specific surface area determined by a BET method of 5 m2/g or less.

Abstract: A solid polymer electrolyte having a high ionic conductivity and a high mechanical strength, and a preparation method therefor. The solid polymer electrolyte comprises a metal salt and a polymer blend of a fluoropolymer and a polyether comprising either or both of an ethylene oxide unit and a propylene oxide unit as a monomeric unit.

Abstract: A process of preparing a positive electrode active material for a nonaqueous secondary battery, comprising: making a buffered aqueous solution of a water-soluble lithium compound and a water-soluble nickel compound having a definite pH, reacting with oxalic acid and a water-soluble lithium compound and a water-soluble nickel compound to yield a co-precipitate of a slightly water-soluble salt of lithium and nickel in the resulting aqueous solution, followed by calcination.

Abstract: A nonaqueous secondary battery includes a working electrode containing graphite particles coated with less crystallized carbon and a nonaqueous electrolyte, which contains at least ethylene carbonate and propylene carbonate.

Abstract: A nonaqueous secondary cell comprises at least one pair of electrodes, and a separator provided between the at least one paired electrodes and impregnated with a nonaqueous electrolyte containing a mixed solvent of propylene carbonate and ethylene carbonate. At least one electrode of the at least one paired electrodes has, at least on surfaces thereof, an active substance layer made of composite carbon particles, which individually comprise a core of crystalline carbon and a low crystallinity or amorphous carbon layer formed on at least a part of the surfaces of the core, and a carbon matrix covering at least a part of the composite carbon particles and uniformly dispersing and holding the composite carbon particles therein.

Abstract: A process of preparing lithium nickel oxide as a positive electrode active material comprising: dissolving a water-soluble lithium compound and a water-soluble nickel compound in water to prepare a homogeneous aqueous solution; co-precipitating, from the aqueous solution, a lithium salt and a nickel salt which are slightly soluble in water; isolating the resulting co-precipitate and calcining the co-precipitate to obtain lithium nickel oxide.

Abstract: A process for preparing lithium nickeloxide (LiNiO.sub.2) for use as a positive electrode active material for a nonaqueous secondary battery, which comprises the steps of: (a) using as the raw materials a lithium compound and a nickel compound at least one of which has a melting point not higher than 300.degree. C.; i) in case where both of the lithium compound and the nickel compound have a melting point not higher than 300.degree. C., mixing the above two compounds after their melting, or mixing the above compounds, melting the mixture and mixing the melted mixture; ii) in case where either one of the lithium compound and the nickel compound has a melting point higher than 300.degree. C., mixing said one having a melting point higher than 300.degree. C. with the remaining one before or after its melting; (b)calcining the resulting mixture at a temperature of 700.degree. C. to 950.degree. C. in air or in an atmosphere containing oxygen in a higher concentration than an atmospheric oxygen concentration.

Abstract: A nonaqueous secondary battery comprising a negative electrode, a positive electrode in which a chalcogenated substance containing lithium is used as a positive electrode active material and a nonaqueous ion conductor, said negative electrode containing a negative electrode active material which is a carbon material where an amorphous carbon is adhered on the surface of graphite particles which are subjected to an oxidizing treatment.

Abstract: A heat exchanging apparatus includes a composite structure of a ferrosoferric oxide and a molybdenum oxide at the internal surface of a heat exchange cycle tube located in a generator. A process of suppressing corrosion of this heat exchanging apparatus includes the step of preparing an ammonia solution including dissolved oxygen of a concentration of approximately 3-8 ppm. Approximately 1 wt %-5 wt % molybdate is added into the ammonia solution. This ammonia solution is sealed within the heat exchange cycle tube to be heated to at least a predetermined temperature in the generator of the heat exchanging apparatus. Thus, a composite structure of a ferrosoferric oxide and molybdenum oxide is formed on the internal surface of the generator. This composite structure allows the suppression of corrosion in the internal surface of the generator.