| 摘要 |
PROBLEM TO BE SOLVED: To lessen capacity deterioration due to charge/discharge cycles and improve discharge characteristics after leaving it standing as it is by causing surfaces of a negative-electrode active material to carry a specific amount of metal elements of at least one kind or more selected from among a group comprising Ti, Pt, Al, Cu, Th, Ce, Fe, Ni, and Mg. SOLUTION: An amount of metal elements carried on surfaces of a negative- electrode active material is set in the range of 0.5 to 20 wt.% relative to the weight of a carbon material. Ethanol is added to distilled water, which is heated at 40 to 80 deg.C, then a carbon material (an artificial graphite powder), a Ti-salt solution and a Pt-salt solution, differing in concentration from each other, are added thereto, a reductant is dripped thereinto while key are stirred, the material is filtered and ringed in water, and then dried, thus a powder is made having Ti and Pt differing in the amount carried thereon from each other. This carbon material and a binder of vinylidene fluoride(PVdF) are mixed together, and N-methyl-2-pyrolidone is added thereto and mixed therewith, thus a slurry-like solution is produced as a negative electrode active material. The slurry-like solution is applied to both surfaces of copper foil, and then the foil is rolled by a roller press and cut, thus a negative electrode is made. |
