| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery capable of being used even in a condition where an upper limit voltage value is high. <P>SOLUTION: The lithium ion secondary battery includes: a positive electrode 530 having a positive electrode active material 534A; a negative electrode 540 having a negative electrode active material 544A; a positive electrode side electrolyte composition E<SB POS="POST">C</SB>(an electrolyte 566) including a nonaqueous solvent and a supporting salt; and a negative electrode side electrolyte composition E<SB POS="POST">A</SB>(an electrolyte gel 567) including a nonaqueous solvent and a supporting salt. The negative electrode active material 544A is covered with the electrolyte gel 567 including the nonaqueous solvent and the supporting salt. An oxidation potential (to Li/Li<SP POS="POST">+</SP>) of the nonaqueous solvent included in the electrolyte composition E<SB POS="POST">C</SB>is higher than an oxidation potential (to Li/Li<SP POS="POST">+</SP>) of the nonaqueous solvent included in the electrolyte composition E<SB POS="POST">A</SB>. When a lithium ion conductivity of the electrolyte 566 and a lithium ion conductivity of the electrolyte gel 567 before gelation are represented as R<SB POS="POST">X</SB>and R<SB POS="POST">Y</SB>, respectively, R<SB POS="POST">X</SB>and R<SB POS="POST">Y</SB>satisfy a relation of R<SB POS="POST">X</SB><R<SB POS="POST">Y</SB>. <P>COPYRIGHT: (C)2012,JPO&INPIT |
