| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery having high capacity and excellent cycle characteristics. <P>SOLUTION: A wound electrode body having a laminate structure with a positive electrode, a negative electrode, and a separator is stored in a battery can. A negative electrode 10 includes a negative electrode active material layer 2 provided over a negative electrode current collector 1. The negative electrode active material layer 2 includes lithium fluosilicate (Li<SB POS="POST">x</SB>SiF<SB POS="POST">y</SB>) as a negative electrode active material. Therefore, since an SEI coating film is not excessively formed, distension of the negative electrode active material layer 2 due to repeat of charge and discharge is prevented and stable occlusion and desorption of a lithium ion is continued. Moreover, since the surface of the negative electrode active material is covered by a coating film made of a fluorine-containing compound such as polyvinylidene fluoride, decomposition reaction of the negative electrode active material due to acidic impurities in electrolytic solution is prevented. <P>COPYRIGHT: (C)2012,JPO&INPIT |
