Abstract: A power storage device that is less likely to be influenced by an ambient temperature is provided. The power storage device capable of being charged and discharged even in a low-temperature environment is provided. A first secondary battery capable of being charged and discharged even at low temperatures and a general second secondary battery are adjacent to each other in the power storage device. The power storage device having such a structure can use, as an internal heat source in a low-temperature environment, heat generated by charge and discharge of the secondary battery capable of being charged and discharged even at low temperatures. Specifically, the power storage device includes the first secondary battery and the second secondary battery adjacent to each other, the first secondary battery has flexibility, and a value of discharge capacity in discharge at ?40° C. is higher than or equal to 50% of a value of discharge capacity in discharge at 25° C.

Abstract: A positive electrode active material that is unlikely to generate defects even when charging and discharging at a high voltage and/or at a high temperature is provided. A positive electrode active material in which crystal structures are unlikely to collapse even when charging and discharging are repeated is also provided. The positive electrode active material contains lithium, cobalt, oxygen, and an additive element. The positive electrode active material includes a surface portion, an inner portion. The positive electrode active material contains the additive element in the surface portion. The surface portion is a region extending from a surface of the positive electrode active material to a depth of 10 nm or less toward the inner portion, and the surface portion and the inner portion are topotaxy. A degree of diffusion of the additive element vary between crystal planes of the surface portion, and the additive element is at least one or two or more selected from nickel, aluminum, and magnesium.

Abstract: A novel bendable and highly portable information processor is provided. In addition, a novel information processor capable of displaying information or the like on a seamless large screen is provided. A novel information processor in which one display region can be divided into two regions at a bend position is provided. A novel information processor in which different images or images for different purposes can be displayed in the respective regions is provided. The present inventors have conceived a program including a step of dividing the display region and displaying image data in the respective regions when a display unit of the information processor is bent.

Abstract: A novel light-emitting device is provided. A light-emitting device with high emission efficiency is provided. A light-emitting device with a long lifetime is provided. A light-emitting device with low driving voltage is provided. The light-emitting device includes an anode, a cathode, and an EL layer between the anode and the cathode. The EL layer includes a hole-injection layer, a light-emitting layer, and an electron-transport layer. The hole-injection layer is positioned between the anode and the light-emitting layer. The electron-transport layer is positioned between the light-emitting layer and the cathode. The hole-injection layer contains a first substance and a second substance. The first substance is an organic compound which has a hole-transport property and a HOMO level higher than or equal to ?5.7 eV and lower than or equal to ?5.4 eV. The second substance exhibits an electron-accepting property with respect to the first substance.

Abstract: A novel bendable and highly portable information processor is provided. In addition, a novel information processor capable of displaying information or the like on a seamless large screen is provided. A novel information processor in which one display region can be divided into two regions at a bend position is provided. A novel information processor in which different images or images for different purposes can be displayed in the respective regions is provided. The present inventors have conceived a program including a step of dividing the display region and displaying image data in the respective regions when a display unit of the information processor is bent.

Abstract: A display device having a photosensing function is provided. A display device having a biometric authentication function typified by fingerprint authentication is provided. A display device having a touch panel function and a biometric authentication function is provided. The display device includes a first substrate, a light guide plate, a first light-emitting element, a second light-emitting element, and a light-receiving element. The first substrate and the light guide plate are provided to face each other. The first light-emitting element and the light-receiving element are provided between the first substrate and the light guide plate. The first light-emitting element has a function of emitting first light through the light guide plate. The second light-emitting element has a function of emitting second light to a side surface of the light guide plate.

Abstract: A novel light-emitting device is provided. A light-emitting device with high emission efficiency is provided. A light-emitting device with a long lifetime is provided. A light-emitting device with low driving voltage is provided. The light-emitting device includes an anode, a cathode, and an EL layer between the anode and the cathode. The EL layer includes a hole-injection layer, a light-emitting layer, and an electron-transport layer. The hole-injection layer is positioned between the anode and the light-emitting layer. The electron-transport layer is positioned between the light-emitting layer and the cathode. The hole-injection layer contains a first substance and a second substance. The first substance is an organic compound which has a hole-transport property and a HOMO level higher than or equal to ?5.7 eV and lower than or equal to ?5.4 eV. The second substance exhibits an electron-accepting property with respect to the first substance.

Abstract: A positive electrode active material in which the number of defects that cause deterioration is small or progress of the defect is suppressed is provided. The positive electrode active material is used for a secondary battery. The positive electrode active material contains lithium cobalt oxide containing an additive element. After a cycle test is performed on a cell that uses the positive electrode active material for a positive electrode and a lithium electrode as a counter electrode, the positive electrode active material includes a defect and contains at least the same element as the additive element in a region in the vicinity of the defect. The additive element is contained also in a surface portion of the positive electrode active material.

Abstract: A display device having a photosensing function is provided. A display device having a biometric authentication function typified by fingerprint authentication is provided. A display device having a touch panel function and a biometric authentication function is provided. The display device includes a first substrate, a light guide plate, a first light-emitting element, a second light-emitting element, and a light-receiving element. The first substrate and the light guide plate are provided to face each other. The first light-emitting element and the light-receiving element are provided between the first substrate and the light guide plate. The first light-emitting element has a function of emitting first light through the light guide plate. The second light-emitting element has a function of emitting second light to a side surface of the light guide plate.

Abstract: An electrode with excellent characteristics is provided. An active material with excellent characteristics is provided. A novel silicon material is provided. An electrode includes a plurality of particles and a graphene compound. At least part of the surface of each of the plurality of particles is terminated by a functional group containing oxygen, the graphene compound contains the plurality of particles so as to cover the surrounding of the plurality of particles, and the graphene compound is graphene containing at least one of a carbon atom terminated by a hydrogen atom and a carbon atom terminated by a fluorine atom in a two-dimensional structure formed with a six-membered ring of carbon.

Abstract: An active material particle with little deterioration is provided. A positive electrode active material particle with little deterioration is provided. The electrode includes a first particle group, a second particle group, and a third particle group. A median diameter of the first particle group is greater than a median diameter of the third particle group, and a median diameter of the second particle group is between the median diameter of the first particle group and the median diameter of the third particle group. The electrode is formed through a first step of forming a first mixture including the first particle group, the second particle group, the third particle group, and a solvent; a second step of applying the first mixture onto a current collector; and a third step of performing heating to volatilize the solvent.

Abstract: An electrode with little deterioration or a secondary battery with little deterioration is provided. An electrode includes a first region and a second region. The first region includes a particle containing silicon. The second region includes a particle containing silicon and a graphene compound. The second region is in contact with the first region to cover at least part thereof. Alternatively, an electrode includes a plurality of particles containing silicon and a graphene compound. Each of the plurality of particles containing silicon includes a functional group containing oxygen and carbon, a functional group containing oxygen, or a fluorine atom in at least part of the surface. The graphene compound includes at least one of carbon terminated with hydrogen and carbon terminated with fluorine in a plane of the graphene compound. The graphene compound is in contact with the plurality of particles containing silicon to closely cling thereto.

Abstract: A positive electrode for a secondary battery having excellent cycle performance is provided. The positive electrode for a secondary battery includes a positive electrode current collector layer, a base film, a positive electrode active material layer, and a cap layer; the base film contains titanium nitride; the positive electrode active material layer contains lithium cobalt oxide; and the cap layer contains titanium oxide. The use of titanium nitride for the base film can inhibit oxidation of the positive electrode current collector and diffusion of metal atoms while ensuring an adequate conductivity. The use of titanium oxide for the cap layer can inhibit a side reaction between the positive electrode active material layer and an electrolyte and collapse of a crystal structure of the electrode active material, improving the cycle performance.

Abstract: According to one embodiment of the present invention, a secondary battery that can be used at a wide range of temperatures and is less likely to be influenced by an environmental temperature is provided. Furthermore, a secondary battery with high safety is provided. An electrolyte obtained by mixing an acyclic ester having high temperature characteristics with a fluorinated carbonic ester at 5 vol. % or higher, preferably 20 vol. % or higher, is used for the purpose of reducing interface resistance between an electrode and an electrolyte, whereby a secondary battery capable of operating at a wide range of temperatures, specifically, at temperatures higher than or equal to ?40° C. and lower than or equal to 150° C., preferably higher than or equal to ?40° C. and lower than or equal to 85° C. can be achieved.

Abstract: A negative electrode with little degradation is provided. Alternatively, a novel negative electrode is provided. A secondary battery includes a positive electrode and a negative electrode, and the negative electrode includes a solvent containing fluorine, a current collector, a negative electrode active material, and graphene. The negative electrode further includes a solid electrolyte material and the solid electrolyte material is an oxide. The negative electrode active material may contain fluorine. The secondary battery may include a plurality of electrolytes different from each other. The negative electrode active material is, for example, a material containing one or more elements selected from silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, and indium.

Abstract: A negative electrode active material particle with little deterioration is provided. Alternatively, a novel negative electrode active material particle is provided. Alternatively, a power storage device with little deterioration is provided. Alternatively, a highly safe power storage device is provided. Alternatively, a novel power storage device is provided. The electrode includes an active material and a conductive additive; the active material contains a metal or a compound including one or more elements selected from silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, and indium; the conductive additive contains a graphene compound; and the graphene compound contains fluorine.

Abstract: To provide a light-emitting element in which an organic compound layer can be processed at once by a photolithography technique. A first electrode and an organic compound layer including an electron-injection layer are formed over an insulating surface. The electron-injection layer is the outermost layer of the organic compound layer and contains an organic compound having a basic skeleton and an acid dissociation constant pKa of greater than or equal to 1. A sacrificial layer and a mask are formed over the electron-injection layer and the sacrificial layer is processed into an island shape using the mask. With use of the island-shaped sacrificial layer as a mask, the organic compound layer is processed into an island shape to cover the first electrode. Part of the island-shaped sacrificial layer is removed with an acidic chemical solution to expose the electron-injection layer. A second electrode is formed to cover the electron-injection layer.

Abstract: A plurality of light-emitting elements having a structure in which an organic compound layer as a whole is processed with a photolithography technique is provided. A light-emitting element is formed over an insulating layer and includes a first electrode, a second electrode, and an organic compound layer. The organic compound layer is positioned between the first electrode and the second electrode. The organic compound layer includes a light-emitting layer and an electron-injection layer. The electron-injection layer is in contact with the second electrode, and the electron-injection layer includes an organic compound having a basic skeleton and an acid dissociation constant pKa of 1 or more. Layers included in the organic compound layer have substantially the same contour, and the organic compound layer is separated from organic compound layers of the other light-emitting elements of the plurality of light-emitting elements.

Abstract: One embodiment of the present invention provides a secondary battery that can be used in a wide temperature range and is less likely to be affected by the ambient temperature. A highly safe secondary battery is provided. Use of a positive electrode including a fluorine-containing electrolyte enables a secondary battery that can work in a wide temperature range, specifically, in the range of higher than or equal to ?40° C. and lower than or equal to 85° C., preferably higher than or equal to ?40° C. and lower than or equal to 150° C. An incombustible high molecular material or a nonflammable high molecular material is used for a binder. Furthermore, a solid electrolyte material may be included in the positive electrode to increase non-flammability.

Abstract: A positive electrode active material with high charge and discharge capacity is provided. Alternatively, a positive electrode active material with high charge and discharge voltages is provided. Alternatively, a power storage device that hardly deteriorates is provided. Alternatively, a highly safe power storage device is provided. Alternatively, a novel power storage device is provided. Provided is a positive electrode active material containing lithium, a plurality of transition metals, oxygen, and an impurity element. The positive electrode active material has a first region including a surface portion and a second region provided in an inner portion; the first region and the second region differ in the concentration of a transition metal. An impurity layer is included between the first region and the second region.