| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium secondary battery which prevents deterioration of a negative electrode by making shallow the charging depth of the negative electrode active material and can improve cycle characteristics. <P>SOLUTION: The lithium secondary battery comprises a positive electrode containing a positive electrode active material and a negative electrode containing a negative electrode active material having Si as the main component, and the electric capacity as calculated by multiplying the theoretical capacity of the negative electrode and the mass ratio of the negative electrode active material is established to be 0.75 times or more of the electric capacity calculated by multiplying the theoretical capacity of the positive electrode and the mass ratio of the positive electrode active material. Furthermore, it is desirable that the negative electrode active material is made of a multiphase alloy powder in which Si phase and SiM phase are contained by all means, and any one or both of the X phase and SiX phase is contained, and the quantity of Si phase on the particle surface of the multiphase alloy powder is made smaller than the quantity of Si phase inside the particle. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
