| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a secondary battery having a high capacity and superior cycle characteristics and an anode active material used for the same. <P>SOLUTION: The anode 22 includes an anode active material capable of reaction with lithium. The anode active material contains as a constituent element silicon, boron, carbon, and at least one kind of metal element out of cobalt, titanium, and iron. A boron content is from 4.9 mass% to 19.8 mass% both inclusive, a carbon content is from 4.9 mass% to 19.8 mass% both inclusive, a total of the contents of boron and carbon is from 9.8 mass% to 29.8 mass% both inclusive, and the ratio of the content of silicon to the total of the contents of silicon and the metal element is from 70 mass% to 95 mass% both inclusive. Furthermore, the anode active material is capable of reaction with lithium, and has a reaction phase in which the half width of a diffraction peak obtained by X-ray diffraction is 1° or more. Thereby, cycle characteristics are improved, while maintaining a high capacity. <P>COPYRIGHT: (C)2010,JPO&INPIT |
