| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a secondary battery capable of enhancing cycle characteristics. <P>SOLUTION: The secondary battery includes a positive electrode 21, a negative electrode 22, and an electrolyte, a separator 23 arranged between the positive electrode 21 and the negative electrode 22 is impregnated with the electrolyte. The negative electrode 22 has a negative electrode active material layer on a negative electrode current collector. The negative electrode active material layer contains at least one of silicon and a silicon compound as a negative electrode active material, and satisfies conditional expression (1) of 1.1≤A/B≤1.7 where the porosity in the vicinity of the surface on the negative electrode current collector side is denoted by A and the porosity in the vicinity on the surface on the opposite side to the negative electrode current collector in the negative electrode active material layer is denoted by B. <P>COPYRIGHT: (C)2010,JPO&INPIT |
