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 including carbon, sulfur, and at least one kind of element from among Ag, Zn, Cd, Al, Ga, In, Tl, Si, Ce, Sn, Pb, As, Sb, and Bi. SOLUTION: Carbon serves as a conductive pass to prevent metal or its sulfide from being isolated electrically, as a cushioning material to absorb expansion/shrinkage of the metal or its sulfide, and as a barrier to prevent the metal or its sulfide from being brought into direct contact with an electrolyte. For effective functioning of carbon as an expansion/shrinkage cushioning material, a metallic phase or a metal sulfide phase of a predetermined size is required. For the size, 1μm or more of the phase concentration is preferably one or less on the average in the observation (12×9 square μm) using electron microscope. A metallic element which forms a complex with carbon and sulfur, and forms alloy with Li and discharging Li at a lower potential is desirable as the element, and fourteen kinds of elements such as Ag are available.