▎ 摘　　要

NOVELTY - The device has an electrolyte provided between a positive electrode and a negative electrode. A negative electrode active material layer (203a) includes an uneven silicon layer (211) formed over a negative electrode current collector (201). A silicon oxide layer (213) or a mixed layer includes silicon oxide and silicate compound, where the silicon oxide layer or the mixed layer is in contact with the uneven silicon layer. Graphene (215) is in contact with the silicon oxide layer. The silicon oxide layer or the mixed layer has thickness greater than 2 nm and less than 10 nm. USE - Power storage device e.g. lithium-ion secondary battery such as sealing-type lithium-ion secondary battery, cylindrical lithium-ion secondary battery and square-type lithium-ion secondary battery, for use in an electric appliance e.g. air conditioner, and installation lighting device provided in a ceiling, a wall, a floor or a window, electric rice cooker, display device e.g. semiconductor display device such as liquid crystal display device, light-emitting device, electrophoresis display device, digital micromirror device (DMD), plasma display panel (PDP), field emission display (FED), used in information display device e.g. personal computer or advertisement display, laptop personal computer, image reproduction device, mobile phone, portable game machine, portable information terminal, electronic-book reader, video camera, digital still camera, high-frequency heating apparatus such as microwaves, electric rice cookers, electric washing machines, air-conditioning systems such as air conditioners, electric refrigerators, electric freezers, electric refrigerator-freezers, freezers for preserving DNA and dialysis devices. Can also be used for a lithium-ion capacitor and air cell used in a tabletop lighting device. ADVANTAGE - The negative electrode is mounted on the device to perform charge and discharge at high speed, which enables the device to have improved charge and discharge capacity. The device includes a space between adjacent projected portions and contact between the projected portions can be prevented even when the negative electrode active material layer is expanded due to charge, thus preventing collapse and peeling of the negative electrode active material layer caused by the expansion of the projected portions, and hence improving cycle performance in which little deterioration due to charge and discharge occurs is manufactured. The silicon oxide layer is provided over the silicon layers to relax expansion and contraction of the silicon layers caused by charge and discharge to suppress the collapse of the silicon layers. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for manufacturing a power storage device. DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a negative electrode. Negative electrode current collector (201) Negative electrode active material layer (203a) Uneven silicon layer (211) Silicon oxide layer (213) Graphene (215)