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: 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: 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: 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: An electric double layer capacitor, a lithium ion capacitor, and a charging device including a solar cell and either of the capacitors are disclosed. The electric double layer capacitor includes a first and second light-transmitting substrates; a pair of current collectors provided perpendicular to the substrates; active material layers provided on facing planes of the current collectors; and an electrolyte in a region surrounded by the substrates and the facing active material layers. The lithium ion capacitor includes a first and second light-transmitting substrates; a positive and negative electrode active material layers provided perpendicular to the substrates; and an electrolyte in a region surrounded by the facing substrates and the positive and negative electrode active material layers.

Abstract: An object is to recover metallic lithium from metallic lithium on which an unnecessary substance is formed without discarding the metallic lithium on which an unnecessary substance is formed. The present invention relates to a method for recovering metallic lithium in such a manner that metallic lithium on which a substance is formed is reacted with nitrogen to form lithium nitride; the lithium nitride is reacted with carbon dioxide to form lithium carbonate; the lithium carbonate is reacted with hydrochloric acid to form lithium chloride; the lithium chloride and potassium chloride are melted; and electrolysis is applied to the melted lithium chloride and potassium chloride.

Abstract: The present invention relates to a solar power generation device which includes an electric double-layer capacitor and a solar cell. The electric double-layer capacitor includes a pair of current collectors formed using a light-transmitting conductive material; active materials which are dispersed on the pair of current collectors; a light-transmitting electrolyte layer which is provided between the pair of current collectors; and a terminal portion which is electrically connected to the current collector. The solar cell includes, over a light-transmitting substrate, a first light-transmitting conductive film; a photoelectric conversion layer which is provided in contact with the first light-transmitting conductive film; and a second light-transmitting conductive film which is provided in contact with the photoelectric conversion layer.

Abstract: A thin energy storage device having high capacity is obtained. An energy storage device having high output is obtained. A current collector and an active material layer are formed in the same manufacturing step. The number of manufacturing steps of an energy storage device is reduced. The manufacturing cost of an energy storage device is suppressed. One embodiment of the present invention relates to an electric double layer capacitor which includes a pair of electrodes including a porous metal material, and an electrolyte provided between the pair of electrodes; or a lithium ion capacitor which includes a positive electrode that is a porous metal body functioning as a positive electrode current collector and a positive electrode active material layer, a negative electrode including a negative electrode current collector and a negative electrode active material layer, and an electrolyte provided between the positive electrode and the negative electrode.