NOVELTY - Operating a power storage device (100), comprises: performing a first charge for charging a stacked structure, including a positive electrode (111), a negative electrode (101) and an electrolyte (121) between the positive electrode and the negative electrode, at a first current value between the positive electrode and the negative electrode; performing a second charge at a first voltage value between the positive electrode and the negative electrode after the first charge; and performing a discharge from the stacked structure at a second current value after the second charge.    USE - The method is useful for operating a power storage device (claimed), where the power storage device is used as a lithium-ion secondary battery, in electronic devices including cameras (i.e. digital cameras or video cameras), digital photo frames, mobile phones (cellular phones or cellular phone devices), portable game machines, portable information terminals or audio reproducing devices, and in electric propulsion vehicles including electric cars, hybrid cars, railway train vehicles, maintenance vehicles, carts or electric wheelchairs.    ADVANTAGE - The method provides the power storage device exhibiting higher discharge capacity and high safety.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for manufacturing (m1) a power storage device, comprising either: forming a stacked structure by providing an electrolyte between a positive electrode and a negative electrode, where the electrolyte includes an ion-conducting high molecular compound, an inorganic oxide, and a lithium electrolyte salt, performing a first charge at a first current value between the positive electrode and the negative electrode, performing a second charge at a first voltage value between the positive electrode and the negative electrode after the first charge, and performing a discharge from the stacked structure at a second current value after the second charge; or forming a stacked structure by providing an electrolyte between a positive electrode and a negative electrode, where the electrolyte is formed by mixing an ion-conducting high molecular compound, an inorganic oxide, and a lithium electrolyte salt, performing a first charge at a first current value between the positive electrode and the negative electrode, performing a second charge at a first voltage value between the positive electrode and the negative electrode after the first charge, and performing a discharge from the stacked structure at a second current value after the second charge.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of the power storage device.    Power storage device (100)    Negative electrode (101)    Positive electrode (111)    Positive electrode current collector (113)    Electrolyte (121)