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: Disclosed is a power storage unit which can safely operate over a wide temperature range. The power storage unit includes: a power storage device; a heater for heating the power storage device; a temperature sensor for sensing the temperature of the power storage device; and a control circuit configured to inhibit charge of the power storage device when its temperature is lower than a first temperature or higher than a second temperature. The first temperature is exemplified by a temperature which allows the formation of a dendrite over a negative electrode of the power storage device, whereas the second temperature is exemplified by a temperature which causes decomposition of a passivating film formed over a surface of a negative electrode active material.

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: An object of an embodiment of the present invention to be disclosed is to prevent oxygen from being taken in a single crystal semiconductor layer in laser irradiation even when crystallinity of the single crystal semiconductor layer is repaired by irradiation with a laser beam; and to make substantially equal or reduce an oxygen concentration in the semiconductor layer after the laser irradiation comparing before the laser irradiation. A single crystal semiconductor layer which is provided over a base substrate by bonding is irradiated with a laser beam, whereby the crystallinity of the single crystal semiconductor layer is repaired. The laser irradiation is performed under a reducing atmosphere or an inert atmosphere.

Abstract: To inhibit degradation of charge and discharge cycle characteristics of a secondary battery. To suppress generation of defects due to expansion and contraction of an active material in a negative electrode. To inhibit deterioration of an electrode due to changes in its form. An electrode member including a current collector, an active material, and a porous body is used. The porous body is in contact with one surface of the current collector and includes a plurality of spaces. The active material is located in the space in the porous body. The space has a larger size than the active material.

Abstract: One of objects is to reduce the effect caused by the volume expansion of an active material. An embodiment is a method for manufacturing an electrode for a power storage device which includes an active material over one of surfaces of a current collector. The active material is formed by forming a conductive body functioning as the current collector; forming a mixed layer including an amorphous region and a microcrystalline region over one of surfaces of the conductive body; and etching the mixed layer selectively, so that a part of or the whole of the amorphous region is removed and the microcrystalline region is exposed. Thus, the effect caused by the volume expansion of the active material is reduced.

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: An object of one embodiment of the present invention is to provide a secondary battery in which deterioration of charge-discharge cycle characteristics is suppressed, to suppress generation of defects caused by expansion and contraction of an active material in a negative electrode, or to prevent deterioration caused by deformation of a secondary battery. To prevent deterioration, a material that can be alloyed with lithium and fluidified easily is used for a negative electrode. To hold a negative electrode active material over a surface of a current collector, a covering layer that covers the negative electrode active material is provided. Furthermore, a portion where the current collector and the negative electrode active material are in contact with each other is alloyed. In other words, an alloy that is in contact with both the current collector and the negative electrode active material is provided in the negative electrode.

Abstract: To increase the capacity and energy density of a secondary battery by using a novel material as a material for a negative electrode in order to increase the amount of lithium ions transferred in charge and discharge. In the case where the negative electrode includes a current collector and a negative electrode active material layer, gallium is used as the negative electrode active material, and the negative electrode active material layer contains resin at 2 wt % or more, preferably 10 wt % or more, adhesion between the current collector and the negative electrode active material can be increased. This inhibits separation between the current collector and the negative electrode active material due repeated expansion and contraction, resulting in longer lifetime of the secondary battery.

Abstract: After a single crystal semiconductor layer provided over a base substrate by attaching is irradiated with a laser beam, characteristics thereof are improved by first heat treatment, and after adding an impurity element imparting conductivity to the single crystal semiconductor layer, second heat treatment is performed at lower temperature than that of the first heat treatment.

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.

Abstract: A single crystal semiconductor substrate is irradiated with ions that are generated by exciting a hydrogen gas and are accelerated with an ion doping apparatus, thereby forming a damaged region that contains a large amount of hydrogen. After the single crystal semiconductor substrate and a supporting substrate are bonded, the single crystal semiconductor substrate is heated to be separated along the damaged region. While a single crystal semiconductor layer separated from the single crystal semiconductor substrate is heated, this single crystal semiconductor layer is irradiated with a laser beam. The single crystal semiconductor layer undergoes re-single-crystallization by being melted through laser beam irradiation, thereby recovering its crystallinity and planarizing the surface of the single crystal semiconductor layer.

Abstract: To provide a power storage device, an operation condition of which is easily analyzed. A secondary battery includes a sensor that is a measurement unit, a microcontroller unit that is a determination unit, and a memory that is a memory unit. With the sensor, conditions of the secondary battery such as the remaining battery power, the voltage, the current, and the temperature are measured. The microcontroller unit performs arithmetic processing of the measurement results and determines the operation condition of the secondary battery. Further, the microcontroller unit stores the measurement result in the memory in accordance with the operation condition of the secondary battery.

Abstract: An object is to inhibit a decrease in the capacity of a power storage device or to compensate the capacity, by adjusting or rectifying an imbalance between a positive electrode and a negative electrode, which is caused by decomposition of an electrolyte solution at the negative electrode. Provided is a charging method of a power storage device including a positive electrode using an active material that exhibits two-phase reaction, a negative electrode, and an electrolyte solution. The method includes the steps of, after constant current charging, performing constant voltage charging with a voltage that does not cause decomposition of the electrolyte solution until a charging current becomes lower than or equal to a lower current value limit; and after the constant voltage charging, performing additional charging with a voltage that causes decomposition of the electrolyte solution until a resistance of the power storage device reaches a predetermined resistance.

Abstract: To provide a highly reliable power storage device, to improve the security of a power storage device, and to suppress deterioration of a power storage device, a power storage device includes, inside an exterior material, a positive electrode, a negative electrode facing the positive electrode, an electrolyte solution between the positive electrode and the negative electrode, and an adsorbent. A separation body which is impermeable to the electrolyte solution and permeable to a gas is provided between the electrolyte solution and the adsorbent.

Abstract: Deterioration of a power storage device is reduced. Switches that control the connections of a plurality of power storage devices separately are provided. The switches are controlled with a plurality of control signals, so as to switch between charge and discharge of each of the power storage devices or between serial connection and parallel connection of the plurality of power storage devices. Further, a semiconductor circuit having a function of carrying out arithmetic is provided for the power storage devices, so that a control system of the power storage devices or a power storage system is constructed.

Abstract: A decrease in the capacity of a power storage device is inhibited by adjusting or reducing imbalance in the amount of inserted and extracted carrier ions between positive and negative electrodes, which is caused by decomposition of an electrolyte solution of the negative electrode. Further, the capacity of the power storage device can be restored. Furthermore, impurities in the electrolyte solution can be decomposed with the use of the third electrode. A power storage device including positive and negative electrodes, an electrolyte, and a third electrode is provided. The third electrode has an adequate electrostatic capacitance. The third electrode can include a material with a large surface area. In addition, a method for charging the power storage device including the steps of performing charging by applying a current between the positive and negative electrodes, and performing additional applying a current between the third electrode and the negative electrode is provided.

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.

Abstract: To improve the long-term cycle performance of a lithium-ion battery or a lithium-ion capacitor by minimizing the decomposition reaction of an electrolytic solution and the like as a side reaction of charge and discharge in the repeated charge and discharge cycles of the lithium-ion battery or the lithium-ion capacitor. A current collector and an active material layer over the current collector are included in an electrode for a power storage device. The active material layer includes a plurality of active material particles and silicon oxide. The surface of one of the active material particles has a region that is in contact with one of the other active material particles. The surface of the active material particle except the region is partly or entirely covered with the silicon oxide.

Abstract: To improve the reliability of a power storage device. A granular active material including carbon is used, and a net-like structure is formed on part of a surface of the granular active material. In the net-like structure, a carbon atom included in the granular active material is bonded to a silicon atom or a metal atom through an oxygen atom. Formation of the net-like structure suppresses reductive decomposition of an electrolyte solution, leading to a reduction in irreversible capacity. A power storage device using the above active material has high cycle performance and high reliability.