| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the following problems: an irreversible capacity may increase at the first charge and discharge to decrease a battery capacity when silicon oxide is used as a negative electrode active material; and a capacity density of the battery may reduce when an availability of a negative electrode is restricted. <P>SOLUTION: A lithium secondary battery includes: the negative electrode formed by depositing a thin film including silicon and oxygen as the negative electrode active material onto a negative electrode collector by the sputtering method; a positive electrode; and an electrolyte, wherein an oxygen content of the negative electrode active material before the first charge and discharge of the lithium secondary battery is within a range of 15 mass% or more and 30 mass% or less with respect to a sum of silicon and oxygen, and the maximum availability of the negative electrode is within a range of 50% or more and 70% or less. <P>COPYRIGHT: (C)2011,JPO&INPIT |
