| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery furnished with both high mass energy density and excellent cycle characteristics (capacity retention ratio at a long-term use). <P>SOLUTION: With the secondary battery provided with a negative electrode having carbon and an alloy as a negative electrode active material of a laminated structure, a positive electrode capable of storing and discharging lithium ion, and an electrolyte arranged between the positive electrode and the negative electrode, Li content of an alloy layer in the negative electrode at a discharging depth of 100% is to be 31% to 67%. <P>COPYRIGHT: (C)2003,JPO |
