NOVELTY - Manufacturing a power storage device involves forming an active material layer (103) over a current collector (101); removing a natural oxide film over active material layer; forming solid electrolyte layer over active material layer after the natural oxide film is removed; and providing a second electrolyte so as to be in contact with the solid electrolyte layer.    USE - For manufacturing a power storage device (claimed); used as secondary battery included in power receiving device in radio frequency (RF) power feeding system; used in electronic devices e.g. cameras such as digital cameras or video cameras, digital photo frames, mobile phones, portable game machines, portable information terminals, or audio reproducing devices, electric propulsion vehicles such as electric vehicles, hybrid vehicles, electric railway vehicles, maintenance vehicles, carts, or wheelchairs.    ADVANTAGE - With the use of the secondary battery in the RF power feeding system, the amount of power storage can be made larger than that in a conventional secondary battery. Thus, the time interval of the wireless power feeding can be lengthened (frequent power feeding can be omitted). In addition, with the use of the secondary battery in the RF power feeding system, the power receiving device can be formed to be compact and lightweight if the amount of power storage with which the power load portion can be driven is the same as that in a conventional secondary battery. Thus, the total cost can be reduced. During the electrode fabrication, the oxide film having low conductivity which is formed on the surface of the active material layer is removed, and the solid electrolyte layer is formed over the active material layer. Consequently, the conductivity of the electrode is improved, and the decomposition and deterioration of the electrolyte solution which are caused by contact between the electrode and the electrolyte solution can be reduced. Moreover, use of such an electrode can bring about an improvement in cycle characteristics of the power storage device.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for power storage device comprising electrode having a current collector; and an active material layer over the current collector; solid electrolyte layer over the active material layer; and a second electrolyte in contact with the solid electrolyte layer.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of manufacturing a power storage device.    Current collector (101)    Active material layer (103)    Crystalline silicon regions (103a, 103b)    Mixed layer (107)    Metal oxide layer (109)