Abstract: A lithium-ion storage battery with a favorable cycle life at high temperatures is provided. A lithium-ion storage battery with a longer lifetime due to reduction of the capacity decrease is provided. A lithium-ion storage battery where reaction between a positive electrode active material and an electrolyte in an electrolyte solution is inhibited is provided. One embodiment of the present invention is a lithium-ion storage battery including a positive electrode, a negative electrode, an electrolyte solution. The positive electrode includes an active material, the active material includes a metal, and the electrolyte solution includes at least one of LiTFSA and LiFSA. Note that, in the lithium-ion storage battery of one embodiment of the present invention, the positive electrode may include a current collector, and the current collector may include Al. In the lithium-ion storage battery, the electrolyte solution may further include LiPF6.

Abstract: Provided is an electrode including a current collector and an active material layer. The active material layer includes an active material, a film including silicone, a conductive additive, and a binder. The active material is in the form of a particle. The film including silicone covers at least part of the active material.

Abstract: The cycle performance of a lithium-ion secondary battery or a lithium-ion capacitor can be obtained by minimizing the decomposition reaction of an electrolytic solution, etc. in the repeated charge and discharge cycles of the lithium-ion secondary battery or the lithium-ion capacitor. An electrode includes a current collector and an active material layer over the current collector. The active material layer includes active material particles, a conductive additive, a binder, and a film containing silicon oxide as its main component. The surface of one of the active material particles includes at least one of a region in contact with the surface of another active material particle, a region in contact with the conductive additive, and a region in contact with the binder. The surface of the active material particle except these regions is at least partly in contact with the film containing silicon oxide as its main component.