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 power storage device including a negative electrode having high cycle performance in which little deterioration due to charge and discharge occurs is manufactured. A power storage device including a positive electrode, a negative electrode, and an electrolyte provided between the positive electrode and the negative electrode is manufactured, in which the negative electrode includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer includes an uneven silicon layer formed over the negative electrode current collector, a silicon oxide layer or a mixed layer which includes silicon oxide and a silicate compound and is in contact with the silicon layer, and graphene in contact with the silicon oxide layer or the mixed layer including the silicon oxide and the silicate compound.

Abstract: A power storage device a positive electrode including a positive electrode active material layer and a negative electrode including a negative electrode active material layer. The positive electrode active material layer includes a plurality of particles of x[Li2MnO3]-(1-x)[LiCo1/3Mn1/3Ni1/3O2] (obtained by assigning 0.5 to x, for example) which is a positive electrode active material, and multilayer graphene with which the plurality of particles of the positive electrode active material are at least partly connected to each other. In the multilayer graphene, a plurality of graphenes are stacked in a layered manner. The graphene contains a six-membered ring composed of carbon atoms, a poly-membered ring which is a seven or more-membered ring composed of carbon atoms, and an oxygen atom bonded to one or more of the carbon atoms in the six-membered ring and the poly-membered ring, which is a seven or more-membered ring.

Abstract: A negative electrode for a secondary battery and a secondary battery using the negative electrode are provided. The negative electrode includes a current collector, an active material layer, and a high molecular material layer. The current collector includes a plurality of protrusion portions extending substantially perpendicularly and a base portion which includes the same material as the plurality of protrusion portions and is connected to the plurality of protrusion portions. The protrusion portions and the active material layer covering the protrusion portions form negative electrode protrusion portions. The base portion and the active material layer covering the base portion form a negative electrode base portion. Part of side surfaces of the negative electrode protrusion portions including basal portions thereof and a top surface of the negative electrode base portion are covered with the high molecular material layer.

Abstract: A power storage device which has high charge/discharge capacity and less deterioration in battery characteristics due to charge/discharge and can perform charge/discharge at high speed is provided. A power storage device includes a negative electrode. The negative electrode includes a current collector and an active material layer provided over the current collector. The active material layer includes a plurality of protrusions protruding from the current collector and a graphene provided over the plurality of protrusions. Axes of the plurality of protrusions are oriented in the same direction. A common portion may be provided between the current collector and the plurality of protrusions.

Abstract: A power storage device in which silicon is used as a negative electrode active material layer and which can have an improved performance such as higher discharge capacity, and a method for manufacturing the power storage device are provided. A power storage device includes a current collector and a silicon layer having a function as an active material layer over the current collector. The silicon layer includes a thin film portion in contact with the current collector, a plurality of bases, and a plurality of whisker-like protrusions extending from the plurality of bases. A protrusion extending from one of the plurality of bases is partly combined with a protrusion extending from another one of the plurality of bases.

Abstract: To provide a carbon-based negative electrode material which can be used with an electrolyte containing PC as a main ingredient, a carbon-based negative electrode material having a graphene layer structure is crystalline and has pores. That is, the crystal structure of the carbon-based negative electrode material is distorted more significantly than that of graphite. Accordingly, the carbon-based negative electrode material has a larger interlayer distance between graphenes than graphite. It has been shown that such a negative electrode material can be used for a secondary battery which contains an electrolyte containing PC as a main ingredient.

Abstract: A power storage device including a negative electrode having high cycle performance in which little deterioration due to charge and discharge occurs is manufactured. A power storage device including a positive electrode, a negative electrode, and an electrolyte provided between the positive electrode and the negative electrode is manufactured, in which the negative electrode includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer includes an uneven silicon layer formed over the negative electrode current collector, a silicon oxide layer or a mixed layer which includes silicon oxide and a silicate compound and is in contact with the silicon layer, and graphene in contact with the silicon oxide layer or the mixed layer including the silicon oxide and the silicate compound.

Abstract: An electrode for a power storage device with good cycle characteristics and high charge/discharge capacity is provided. In addition, a power storage device including the electrode is provided. The electrode for the power storage device includes a conductive layer and an active material layer provided over the conductive layer, the active material layer includes graphene and an active material including a plurality of whiskers, and the graphene is provided to be attached to a surface portion of the active material including a plurality of whiskers and to have holes in part of the active material layer. Further, in the electrode for the power storage device, the graphene is provided to be attached to a surface portion of the active material including a plurality of whiskers and to cover the active material including a plurality of whiskers. Further, the power storage device including the electrode is manufactured.

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: To provide a power storage device having excellent charge/discharge cycle characteristics and a high charge/discharge capacity. The following electrode is used as an electrode of a power storage device: an electrode including a current collector and an active material layer provided over the current collector. The active material layer includes a plurality of whisker-like active material bodies. Each of the plurality of whisker-like active material bodies includes at least a core and an outer shell provided to cover the core. The outer shell is amorphous, and a portion between the current collector and the core of the active material bodies is amorphous. Note that a metal layer may be provided instead of the current collector, the active material bodies do not necessarily have to include the core, and a mixed layer may be provided between the current collector and the active material layer.

Abstract: To provide graphene through which ions can transfer in the direction perpendicular to a plane of the graphene. Multilayer graphene includes a plurality of graphenes stacked in a layered manner. The plurality of graphenes contain a six-membered ring composed of carbon atoms, a poly-membered ring which is a seven or more-membered ring composed of carbon atoms or carbon atoms and one or more oxygen atoms, and an oxygen atom bonded to one of the carbon atoms in the six-membered ring and the poly-membered ring, which is a seven or more-membered ring. The interlayer distance between adjacent graphenes of the plurality of graphenes is greater than 0.34 nm and less than or equal to 0.5 nm, preferably greater than or equal to 0.38 nm and less than or equal to 0.42 nm.

Abstract: An object is to provide graphene which has high conductivity and is permeable to ions of lithium or the like. Another object is to provide, with use of the graphene, a power storage device with excellent charging and discharging characteristics. Graphene having a hole inside a ring-like structure formed by carbon and nitrogen has conductivity and is permeable to ions of lithium or the like. The nitrogen concentration in graphene is preferably higher than or equal to 0.4 at. % and lower than or equal to 40 at. %. With use of such graphene, ions of lithium or the like can be preferably made to pass; thus, a power storage device with excellent charging and discharging characteristics can be provided.

Abstract: To increase the conductivity and electric capacity of an electrode which includes active material particles and the like and is used in a battery, a graphene net including 1 to 100 graphene sheets is used instead of a conventionally used conduction auxiliary agent add binder. The graphene net which has a two-dimensional expansion and a three-dimensional structure is more likely to touch active material particles or another conduction auxiliary agent, thereby increasing the conductivity and the bonding strength between active material particles. This graphene net is obtained by mixing graphene oxide and active material particles and then heating the mixture in a vacuum or a reducing atmosphere.

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 negative electrode and a power storage device are provided, which have one of an alloy-based particle and an alloy-based whisker and a carbon film including 1 to 50 graphene layers. A surface of the alloy-based particle or the alloy-based whisker is covered with the carbon film. In addition, a method of manufacturing a negative electrode and a method of manufacturing a power storage device are provided, which have the step of mixing an alloy-based particle or an alloy-based whisker with graphene oxide, and the step of heating the mixture in a vacuum or in a reducing atmosphere.

Abstract: A color image of an inspection object is taken by an imaging means capable of taking a color image to obtain color information of an RGB color space. A gray-scale image of a color component of the RGB color space or another color space is generated, and the inspection object is detected by a pattern recognition technique. Alternatively, a binary image is generated from the generated gray-scale image, and the inspection object is detected by performing pattern recognition on the binary image. Color data of a pixel occupied by the detected inspection object is compared with color data of a non-defective inspection object which is previously prepared to judge whether or not the inspection object is defective. In addition, this judgment result is reflected in another manufacturing step through a network and product quality is improved.

Abstract: To provide a power storage device having a solid electrolyte, in which a charge-discharge capacity can be increased, and a method for manufacturing the power storage device. The power storage device includes a positive electrode, a negative electrode, and an electrolyte provided between the positive electrode and the negative electrode, and the electrolyte includes an ion-conductive high molecular compound, an inorganic oxide, and a lithium salt, and the inorganic oxide is included in the electrolyte at more than 30 wt % and 50 wt % or less to the total of the ion-conductive high molecular compound and the inorganic oxide.

Abstract: A color image of an inspection object is taken by an imaging means capable of taking a color image to obtain color information of an RGB color space. A gray-scale image of a color component of the RGB color space or another color space is generated, and the inspection object is detected by a pattern recognition technique. Alternatively, a binary image is generated from the generated gray-scale image, and the inspection object is detected by performing pattern recognition on the binary image. Color data of a pixel occupied by the detected inspection object is compared with color data of a non-defective inspection object which is previously prepared to judge whether or not the inspection object is defective. In addition, this judgment result is reflected in another manufacturing step through a network and product quality is improved.

Abstract: A color image of an inspection object is taken by an imaging means capable of taking a color image to obtain color information of an RGB color space. A gray-scale image of a color component of the RGB color space or another color space is generated, and the inspection object is detected by a pattern recognition technique. Alternatively, a binary image is generated from the generated gray-scale image, and the inspection object is detected by performing pattern recognition on the binary image. Color data of a pixel occupied by the detected inspection object is compared with color data of a non-defective inspection object which is previously prepared to judge whether or not the inspection object is defective. In addition, this judgment result is reflected in another manufacturing step through a network and product quality is improved.