Hitherto, lithium secondary batteries have been widely used for electronic devices such as mobile telephones, notebook computers, and PDAs. Graphite materials have been widely used as negative electrode active materials for lithium secondary batteries.
Recently, use of materials capable of being alloyed with lithium, such as silicon, as negative electrode active materials have been studied in order to, for example, increase the capacities of lithium secondary batteries. For example, PTL 1 discloses a negative electrode including a negative electrode active material layer including silicon.
However, lithium occluded in a material capable of being alloyed with lithium during the first charge is less likely to be released when discharging is performed subsequently. Therefore, a lithium secondary battery in which a material capable of being alloyed with lithium is used as a negative electrode active material is likely to have a low charge/discharge efficiency during the first charge and discharge and may have a low charge/discharge capacity during the second and later charges and discharges.
In order to address the above issues, for example, PTL 1 discloses a technique in which lithium is occluded into a negative electrode active material layer in advance by depositing metal lithium on the surface of the negative electrode active material layer by a gas phase method.