| 摘要 |
PROBLEM TO BE SOLVED: To provide: a lithium ion secondary battery which is arranged by use of a silicon-containing negative electrode active material, and is superior in practical characteristics; and a manufacturing method thereof.SOLUTION: A lithium ion secondary battery according to an aspect of the present invention in order to solve the problem comprises: a negative electrode active material including a silicon-based active material and a carbon-based active material; and an electrolytic solution including an S=O compound having a structure depending on G/D ratio of the carbon-based active material. According to this aspect, during the time of charging, for example, the S=O compound is decomposed in preference to another solvent (e.g. ethylene carbonate) and then, the negative electrode active material is covered with a product of the decomposition. Thus, the decomposition of the solvent on the negative electrode active material is suppressed. In addition, the decomposition product of the S=O compound never interferes with a lithium ion going into and out of the negative electrode active material. Therefore, the lithium ion secondary battery has enhanced battery characteristics. |
