ACTIVE MATERIAL FOR SECONDARY BATTERY NEGATIVE ELECTRODE AND MANUFACTURE THEREOF

PROBLEM TO BE SOLVED: To exhibit high capacity in a Li charging/discharging time by specifying a mean grain size of mixture grain of a metal contained in a composite material together with a carbon material to a specific value or less. SOLUTION: As a metal element for forming a complex with carbon in a composite material, an element which forms an alloy with Li and discharging Li at a lower potential as against oxidation-reduction potential of Li is favorable. As this kind of element, Ag, Zn, Cd, Al, Ga, In, Tl, Ce, Sn, Pb, As, Sb, Bi are available. A mixture mean grain size of at least one kind of metal selected from these elements or its alloy is 10 μm or less. These grains are preferably dispersed in carbon material. Active material for a negative electrode is obtained by burning the organic metal compound containing these metal elements. In this case, for controlling a mixing ratio of carbon to metal, a mixture of the organic metal compound and pitch or the like, a precursor of carbon, is preferably used.