| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery in which alloying with lithium is suppressed and cycle characteristics are improved, and weight reduction and cost reduction are made possible. <P>SOLUTION: The lithium ion secondary battery has a positive electrode, including a current collector and an active material layer; a negative electrode having the current collector and an active material layer to contain an active material (however, except graphite) containing an element capable of alloying with lithium; and an electrolytic solution containing support salt. The current collector of the negative electrode is made of aluminum, the content of the support salt in the electrolytic solution is higher than 0.4 M of saturated solubility or lower, and the support salt contains at least one kind selected from among a group consisting of lithium salt of borate of chemical formula (1), lithium salt of phosphoric acid ester of a specific structure, and imide lithium salt of a specific structure. <P>COPYRIGHT: (C)2011,JPO&INPIT |
