Abstract: To provide a power storage device whose charge and discharge characteristics are unlikely to be degraded by heat treatment. To provide a power storage device that is highly safe against heat treatment. The power storage device includes a positive electrode, a negative electrode, a separator, an electrolytic solution, and an exterior body. The separator is located between the positive electrode and the negative electrode. The separator contains polyphenylene sulfide or solvent-spun regenerated cellulosic fiber. The electrolytic solution contains a solute and two or more kinds of solvents. The solute contains LiBETA. One of the solvents is propylene carbonate.

Abstract: A secondary battery with little deterioration is provided. A secondary battery with high safety is provided. A separator having excellent characteristics is provided. A separator achieving the secondary battery with high safety is provided. A novel separator is provided. In the separator, a polymer porous film and a layer including a ceramic-based material containing a metal oxide microparticle are stacked, the thickness of the layer including a ceramic-based material is greater than or equal to 1 ?m and less than or equal to 100 ?m, and the film thickness of the polymer porous film is greater than or equal to 4 ?m and less than or equal to 50 ?m.

Abstract: A composite oxide with high diffusion rate of lithium is provided. Alternatively, a lithium-containing complex phosphate with high diffusion rate of lithium is provided. Alternatively, a positive electrode active material with high diffusion rate of lithium is provided. Alternatively, a lithium ion battery with high output is provided. Alternatively, a lithium ion battery that can be manufactured at low cost is provided. A positive electrode active material is formed through a first step of mixing a lithium compound, a phosphorus compound, and water, a second step of adjusting pH by adding a first aqueous solution to a first mixed solution formed in the first step, a third step of mixing an iron compound with a second mixed solution formed in the second step, a fourth step of performing heat treatment under a pressure more than or equal to 0.1 MPa and less than or equal to 2 MPa at a highest temperature more than 100° C. and less than or equal to 119° C.

Abstract: A parameter candidate for a semiconductor element is provided. A data set of measurement data is provided to a parameter extraction portion, and a model parameter is extracted. A first netlist is provided to a circuit simulator, simulation is performed using the first netlist and the model parameter, and a first output result is output. A classification model learns the model parameter and the first output result and classifies the model parameter. A second netlist and a model parameter are provided to the circuit simulator. A variable to be adjusted is supplied to a neural network, an action value function is output, and the variable is updated. The circuit simulator performs simulation using the second netlist and the model parameter. When a second output result to be output does not satisfy conditions, a weight coefficient of the neural network is updated. When the second output result satisfies the conditions, the variable is judged to be the best candidate.

Abstract: To form graphene to a practically even thickness on an object having an uneven surface or a complex surface, in particular, an object having a surface with a three-dimensional structure due to complex unevenness, or an object having a curved surface. The object and an electrode are immersed in a graphene oxide solution, and voltage is applied between the object and the electrode. At this time, the object serves as an anode. Graphene oxide is attracted to the anode because of being negatively charged, and deposited on the surface of the object to have a practically even thickness. A portion where graphene oxide is deposited is unlikely coated with another graphene oxide. Thus, deposited graphene oxide is reduced to graphene, whereby graphene can be formed to have a practically even thickness on an object having surface with complex unevenness.

Abstract: A secondary battery with little deterioration is provided. A highly reliable secondary battery is provided. A positive electrode active material included in the secondary battery includes a crystal of lithium cobalt oxide. The positive electrode active material includes a first region including a surface parallel to the (00l) plane of the crystal and a second region including a surface parallel to a plane intersecting with the (00l) plane. The positive electrode active material contains magnesium. The first region includes a portion with a magnesium concentration that is higher than or equal to 0.5 atomic % and lower than or equal to 10 atomic %. The second region includes a portion with a magnesium concentration that is higher than the magnesium concentration in the first region and is higher than or equal to 4 atomic % and lower than or equal to 30 atomic %.

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: Described herein is a positive electrode comprising an active material particle, an acetylene black particle and net-like graphene. The positive electrode can be used in a battery.

Abstract: A secondary battery in which graphite that is an active material can occlude and release lithium efficiently is provided. Further, a highly reliable secondary battery in which the amount of lithium inserted and extracted into/from graphite that is an active material is prevented from varying is provided. The secondary battery includes a negative electrode including a current collector and graphite provided over the current collector, and a positive electrode. The graphite includes a plurality of graphene layers. Surfaces of the plurality of graphene layers are provided substantially along the direction of an electric field generated between the positive electrode and the negative electrode.

Abstract: Graphene is formed with a practically uniform thickness on an uneven object. The object is immersed in a graphene oxide solution, and then taken out of the solution and dried; alternatively, the object and an electrode are immersed therein and voltage is applied between the electrode and the object used as an anode. Graphene oxide is negatively charged, and thus is drawn to and deposited on a surface of the object, with a practically uniform thickness. After that, the object is heated in vacuum or a reducing atmosphere, so that the graphene oxide is reduced to be graphene. In this manner, a graphene layer with a practically uniform thickness can be formed even on a surface of the uneven object.

Abstract: A lithium-ion secondary battery including a lithium-containing complex phosphate as a positive electrode active material is provided. Furthermore, a positive electrode active material with high diffusion rate of lithium ions is provided to provide a lithium-ion secondary battery with high output. A positive electrode active material of a lithium-ion secondary battery includes a first plate-like component and a second plate-like component, a third prismatic component between the first component and the second component, and a space between the first component and the second component.

Abstract: To provide a storage battery including a carbon-based material. To provide a graphene compound film having desired ion conductivity and mechanical strength while preventing direct contact between electrodes in a storage battery. To achieve long-term reliability. A lithium-ion storage battery includes a positive electrode, a negative electrode, an exterior body, and a separator between the positive electrode and the negative electrode. In the lithium-ion storage battery, one of the positive electrode and the negative electrode is wrapped in a first film, and the positive electrode, the negative electrode, and the separator are stored in the exterior body. The first film may include a first region in which the first film includes a first functional group. The first film may further include a second region in which the first film includes a second functional group different from the first functional group. The first film may be a graphene compound film.

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 power storage device with high capacity or high energy density is provided. A highly reliable power storage device is provided. A long-life power storage device is provided. An electrode includes an active material, a first binder, and a second binder. The specific surface area of the active material is S [m2/g]. The weight of the active material, the weight of the first binder, and the weight of the second binder are a, b, and c, respectively. The solution of {(b+c)/(a+b+c)}×100÷S is 0.3 or more. The electrode includes a first film in contact with the active material. The first film preferably includes a region in contact with the active material. The first film preferably includes a region with a thickness of 2 nm or more and 20 nm or less. The first film contains a water-soluble polymer.

Abstract: A lithium-ion secondary battery including a lithium-containing complex phosphate as a positive electrode active material is provided. Furthermore, a positive electrode active material with high diffusion rate of lithium ions is provided to provide a lithium-ion secondary battery with high output. A positive electrode active material of a lithium-ion secondary battery includes a first plate-like component and a second plate-like component, a third prismatic component between the first component and the second component, and a space between the first component and the second component.

Abstract: Graphene is formed with a practically uniform thickness on an uneven object. The object is immersed in a graphene oxide solution, and then taken out of the solution and dried; alternatively, the object and an electrode are immersed therein and voltage is applied between the electrode and the object used as an anode. Graphene oxide is negatively charged, and thus is drawn to and deposited on a surface of the object, with a practically uniform thickness. After that, the object is heated in vacuum or a reducing atmosphere, so that the graphene oxide is reduced to be graphene. In this manner, a graphene layer with a practically uniform thickness can be formed even on a surface of the uneven object.

Abstract: A secondary battery in which graphite that is an active material can occlude and release lithium efficiently is provided. Further, a highly reliable secondary battery in which the amount of lithium inserted and extracted into/from graphite that is an active material is prevented from varying is provided. The secondary battery includes a negative electrode including a current collector and graphite provided over the current collector, and a positive electrode. The graphite includes a plurality of graphene layers. Surfaces of the plurality of graphene layers are provided substantially along the direction of an electric field generated between the positive electrode and the negative electrode.

Abstract: A position estimation system with low power consumption is provided. The position estimation system includes a comparison unit, a learning unit, a data acquisition unit, an inference unit, a data conversion unit, and an evaluation unit. The comparison unit has a function of calculating a first parallel movement amount and a first rotation amount on the basis of machine learning data representing geographic information. The learning unit has a function of generating a machine learning model through learning using the machine learning data, the first parallel movement amount, and the first rotation amount. The data acquisition unit has a function of acquiring acquisition data representing environmental information on the vicinity of a position estimation device. The inference unit has a function of inferring a second parallel movement amount and a second rotation amount, with use of the machine learning model, on the basis of the acquisition data and the machine learning data.

Abstract: To provide a storage battery including a carbon-based material. To provide a graphene compound film having desired ion conductivity and mechanical strength while preventing direct contact between electrodes in a storage battery. To achieve long-term reliability. A lithium-ion storage battery includes a positive electrode, a negative electrode, an exterior body, and a separator between the positive electrode and the negative electrode. In the lithium-ion storage battery, one of the positive electrode and the negative electrode is wrapped in a first film, and the positive electrode, the negative electrode, and the separator are stored in the exterior body. The first film may include a first region in which the first film includes a first functional group. The first film may further include a second region in which the first film includes a second functional group different from the first functional group. The first film may be a graphene compound film.

Abstract: A data processing system that can sense fatigue or the like using a neural network is provided. First, a reference image is obtained on the basis of first to n-th images (n is an integer greater than or equal to 2). Next, the first to n-th images and the reference image are input to an input layer of a neural network, first to n-th estimated ages and a reference estimated age are output from an output layer, and first to n-th data and reference data are output from an intermediate layer. After that, first to n-th coordinates are obtained in each of which an x-coordinate is a value corresponding to a difference between the reference estimated age and the first to n-th estimated ages and a y-coordinate is a value corresponding to the degree of similarity between the reference data and the first to n-th data.