1. Field of the Invention
The invention disclosed in this specification relates to power storage devices.
2. Description of the Related Art
In recent years, power storage devices, such as lithium-ion secondary batteries, which are power storage devices where carbon or lithium metal oxide is used as a battery material and which are charged and discharged by the movement of lithium ions as carrier ions between a positive electrode and a negative electrode, and electrochemical capacitors, have been actively developed (see References 1 to 3).