Abstract: To provide a positive electrode active material film that does not have a (003) orientation and has a layered rock-salt crystal structure even though an inexpensive substrate such as a glass substrate is used, and a positive electrode including the positive electrode active material film. The positive electrode includes a substrate, a positive electrode current collector film, and the positive electrode active material film. The positive electrode current collector film has a stacked structure of a titanium film and a titanium nitride film. The titanium film has a crystal structure belonging to a space group P63/mmc and a (101) orientation, the titanium nitride film has a crystal structure belonging to a space group Fm-3m and a (311) orientation, and the positive electrode active material film has a layered rock-salt crystal structure and a (116) orientation.

Abstract: A power storage system with excellent characteristics is provided. A power storage system with a high degree of safety is provided. A power storage system with less deterioration is provided. A storage battery with excellent characteristics is provided. The power storage system includes a neural network and a storage battery. The neural network includes an input layer, an output layer, and one or more hidden layers between the input layer and the output layer. The predetermined hidden layer is connected to the previous hidden layer or the previous input layer by a predetermined weight coefficient, and connected to the next hidden layer or the next output layer by a predetermined weight coefficient. In the storage battery, voltage and time at which the voltage is obtained are measured as one of sets of data. The sets of data measured at different times are input to the input layer and the operational condition of the storage battery is changed in accordance with a signal output from the output layer.

Abstract: Interface contact between a polymer electrolyte and an active material layer is improved. A secondary battery with improved discharge capacity is provided. The secondary battery includes a positive electrode, a negative electrode, and an electrolyte layer between the positive electrode and the negative electrode. The positive electrode includes a positive electrode active material, a first lithium-ion conductive polymer, a first lithium salt, and a conductive material over a positive electrode current collector. The electrolyte layer includes a second lithium-ion conductive polymer and a second lithium salt. The conductive material is preferably graphene. The negative electrode preferably includes a negative electrode active material, a third lithium-ion conductive polymer, a third lithium salt, and a second conductive material over a negative electrode current collector.

Abstract: An object is to suppress electrochemical decomposition of an electrolyte solution and the like at a negative electrode in a lithium ion battery or a lithium ion capacitor; thus, irreversible capacity is reduced, cycle performance is improved, or operating temperature range is extended. A negative electrode for a power storage device including a negative electrode current collector, a negative electrode active material layer which is over the negative electrode current collector and includes a plurality of particles of a negative electrode active material, and a film covering pan of the negative electrode active material. The film has an insulating property and lithium ion conductivity.

Abstract: An active material layer that has a high filling rate and a higher density and is formed using a small amount of conductive additive is provided. A positive electrode active material layer includes a first carbon material and a second carbon material, which is more likely to aggregate than the first carbon material, and mixing is performed such that the weight of the second carbon material is more than or equal to 1.5 times and less than or equal to 20 times that of the first carbon material, thereby preventing the aggregation of the second carbon material and the aggregation of the first carbon material and reducing the proportion of the aggregated portions.

Abstract: A power storage system with excellent characteristics is provided. A power storage system with a high degree of safety is provided. A power storage system with less deterioration is provided. A storage battery with excellent characteristics is provided. The power storage system includes a neural network and a storage battery. The neural network includes an input layer, an output layer, and one or more hidden layers between the input layer and the output layer. The predetermined hidden layer is connected to the previous hidden layer or the previous input layer by a predetermined weight coefficient, and connected to the next hidden layer or the next output layer by a predetermined weight coefficient. In the storage battery, voltage and time at which the voltage is obtained are measured as one of sets of data. The sets of data measured at different times are input to the input layer and the operational condition of the storage battery is changed in accordance with a signal output from the output layer.

Abstract: Disclosed is a power storage element including a positive electrode current collector layer and a negative electrode current collector layer which are arranged on the same plane and can be formed through a simple process. The power storage element further includes a positive electrode active material layer on the positive electrode current collector layer; a negative electrode active material layer on the negative electrode current collector layer; and a solid electrolyte layer in contact with at least the positive electrode active material layer and the negative electrode active material layer. The positive electrode active material layer and the negative electrode active material layer are formed by oxidation treatment.

Abstract: A secondary battery with favorable cycle performance is provided. Alternatively, a secondary battery with higher capacity is provided. A positive electrode active material layer including a first graphene layer, a second graphene layer, and a positive electrode active material. The first graphene layer includes a first region covering the positive electrode active material. The second graphene layer includes a second region covering the positive electrode active material and a third region overlapping with the first region. The first region includes a plane positioned between the positive electrode active material and the third region and formed of arranged six-membered carbon rings. The positive electrode active material includes a fourth region with a layered rock-salt structure. A lithium layer with a layered rock-salt structure included in the fourth region is substantially perpendicular to the plane formed of six-membered carbon rings and included in the second region.

Abstract: A method for manufacturing a novel electrode is provided. The method includes the steps of applying, to a current collector, a mixture comprising an active material, a conductive additive comprising a graphene compound, a binder, and a dispersion medium; performing a drying treatment on the mixture; performing a heat treatment on the mixture at a temperature higher than a temperature of the drying treatment; reducing the graphene compound in the mixture by a chemical reaction using a reducing agent; and performing a thermal reduction treatment on the mixture at a temperature higher than the temperature of the heat treatment.

Abstract: To provide a secondary battery in which a side reaction does not easily occur at an interface between a positive electrode active material and a solid electrolyte, an interface between the positive electrode active material and a positive electrode current collector, or the like even when charge and discharge are repeated. In one embodiment of the present invention, a buffer layer or a protective layer is provided on a current collector surface or between a current collector layer and an active material layer to prevent deterioration such as oxidation of the current collector. As the buffer layer or the protective layer, it is possible to use a titanium compound such as titanium oxide, titanium oxide in which nitrogen is substituted for part of oxygen, titanium nitride, titanium nitride in which oxygen is substituted for part of nitrogen, or titanium oxynitride (TiOxNy, where 0<x<2 and 0<y<1).

Abstract: A secondary battery that can withstand at least high temperature is achieved by designing the structure of the secondary battery. The secondary battery uses: a positive electrode active material obtained by a formation method including a first step of forming a first mixture by pulverizing magnesium fluoride, lithium fluoride, a nickel source, and an aluminum source and then mixing the pulverized materials with powder of lithium cobalt oxide, and a second step of forming a second mixture by heating the first mixture at a temperature lower than an upper temperature limit of the lithium cobalt oxide; and an electrolyte solution to which LiBOB is added.

Abstract: A highly reliable solid-state secondary battery with improved cycle performance, reliability, or safety is provided. A negative electrode includes, over a negative electrode current collector, n negative electrode active material layers (n is an integer greater than or equal to 2) and n?1 separation layers. The negative electrode active material layers and the separation layers are alternately stacked. The thickness of the negative electrode active material is greater than or equal to 20 nm and less than or equal to 100 nm. The separation layers each include titanium. The separation layer preferably includes titanium (Ti), titanium nitride (TiN), or titanium oxynitride (TiOxNy, 0<x<2, 0<y<1). With the negative electrode having such a structure, the expansion of each negative electrode active material layer can be reduced. Accordingly, the negative electrode that has high capacity and hardly causes a crack or a breakage can be obtained.

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: A solid-state secondary battery with high charge and discharge characteristics is provided. The solid-state secondary battery includes a first layer and a positive electrode active material layer over a substrate. The first layer and the positive electrode active material layer are in contact with each other; the first layer has conductivity; the first layer has a first crystal structure including first cations and first anions; the positive electrode active material layer has a second structure including second cations and second anions; and a value calculated by the following formula (1) is less than or equal to 0.1 when La denotes the minimum value of a distance between one of the first cations and another one of the first cations in the first crystal structure and Lb denotes the minimum value of a distance between one of the second cations and another one of the second cations.

Abstract: A lithium-ion secondary battery having high capacity and excellent charge and discharge cycle performance is provided. A secondary battery having high capacity is provided. A secondary battery having excellent charge and discharge performance is provided. A secondary battery in which a decrease in capacity is suppressed even at high temperatures is provided. The secondary battery includes a positive electrode, a negative electrode, an electrolyte solution, and an exterior body. The positive electrode includes a positive electrode active material. The positive electrode active material contains lithium, cobalt, oxygen, magnesium, and fluorine. The number of magnesium atoms contained in the positive electrode active material is greater than or equal to 0.001 times and less than or equal to 0.1 times the number of cobalt atoms contained in the positive electrode active material. The positive electrode active material includes a region having a layered rock-salt crystal structure.

Abstract: A solid-state secondary battery with high safety is provided. The solid-state secondary battery includes a first film that has a function of releasing and accumulating a lithium ion and is over a negative electrode current collector layer, a second film that has a function of transporting a lithium ion and is over the first film, a third film that has a function of releasing and accumulating a lithium ion and is over the second film, and a positive electrode current collector layer over the third film. The total thickness of the first to third films is the same before and after charging.

Abstract: An object is to achieve a manufacturing apparatus that can fully automate the manufacturing of a solid-state secondary battery. A mask alignment chamber, a first transfer chamber connected to the mask alignment chamber, a second transfer chamber connected to the first transfer chamber, a first film formation chamber connected to the second transfer chamber, a third transfer chamber connected to the first transfer chamber, and a second film formation chamber connected to the third transfer chamber are included.

Abstract: A semiconductor device in which a circuit and a power storage element are efficiently placed is provided. The semiconductor device includes a first transistor, a second transistor, and an electric double-layer capacitor. The first transistor, the second transistor, and the electric double-layer capacitor are provided over one substrate. A band gap of a semiconductor constituting a channel region of the second transistor is wider than a band gap of a semiconductor constituting a channel region of the first transistor. The electric double-layer capacitor includes a solid electrolyte.

Abstract: A semiconductor device in which a circuit and a battery are efficiently stored is provided. In the semiconductor device, a first transistor, a second transistor, and a secondary battery are provided over one substrate. A channel region of the second transistor includes an oxide semiconductor. The secondary battery includes a solid electrolyte, and can be fabricated by a semiconductor manufacturing process. The substrate may be a semiconductor substrate or a flexible substrate. The secondary battery has a function of being wirelessly charged.

Abstract: A semiconductor device in which a circuit and a battery are efficiently stored is provided. In the semiconductor device, a first transistor, a second transistor, and a secondary battery are provided over one substrate. A channel region of the second transistor includes an oxide semiconductor. The secondary battery includes a solid electrolyte, and can be fabricated by a semiconductor manufacturing process. The substrate may be a semiconductor substrate or a flexible substrate. The secondary battery has a function of being wirelessly charged.