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 material that can be used in a wide temperature range is provided. A graphene compound includes graphene or graphene oxide and a substituted or unsubstituted chain group, the chain group includes two or more ether bonds, and the chain group is bonded to the above graphene or graphene oxide through a Si atom. Alternatively, a method for forming a graphene compound includes a first step and a second step after the first step. In the first step, graphene oxide and a base are stirred under a nitrogen stream. In the second step, the mixture is cooled to room temperature, a silylating agent that has a group having two or more ether bonds is introduced into the mixture, and the obtained mixture is stirred. The base is butylamine, pentylamine, hexylamine, diethylamine, dipropylamine, dibutylamine, triethylamine, tripropylamine, or pyridine.
Abstract:
A novel substance with which an increase in life and emission efficiency of a light-emitting element can be achieved is provided. A carbazole compound having a structure represented by General Formula (G1) is provided. Note that a substituent which makes the HOMO level and the LUMO level of a compound in which a bond of the substituent is substituted with hydrogen deep and shallow, respectively is used as each of substituents in General Formula (G1) (R1, R2, Ar3, and α3). Further, a substituent which makes the band gap (Bg) and the T1 level of a compound in which a bond of the substituent is substituted with hydrogen wide and high is used as each of the substituents in General Formula (G1) (R1, R2, Ar3, and α3).
Abstract:
To provide a light-emitting element with high emission efficiency or long lifetime, in which the use amount of a phosphorescent compound is small. To provide a light-emitting element including a light-emitting layer between a pair of electrodes, wherein the light-emitting layer includes a phosphorescent compound, a first organic compound, and a second organic compound, and the combination of the first organic compound and the second organic compound forms an exciplex. The light-emitting element transfers energy by utilizing the overlap between the emission spectrum of the exciplex and the absorption spectrum of the phosphorescent compound and thus has high energy transfer efficiency, even when the concentration of the phosphorescent compound is low.
Abstract:
An object of one embodiment of the present invention is to provide a novel oxadiazole derivative as a substance having high excitation energy, in particular, a substance having high triplet excitation energy. One embodiment of the present invention is an oxadiazole derivative represented by General Formula (G1) below. In General Formula (G1), R1 represents either an alkyl group having 1 to 4 carbon atoms or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. In General Formula (G1), R21 to R27 separately represent any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. In General Formula (G1), α represents a substituted or unsubstituted arylene group having 6 to 13 carbon atoms. In General Formula (G1), Z represents either a sulfur atom or an oxygen atom.
Abstract:
A quinoxaline derivative that is a novel organic compound is provided. A quinoxaline derivative represented by General Formula (G1) has a structure in which a quinoxaline skeleton is bonded to the 9-position of an anthracene skeleton, the 10-position of the anthracene skeleton is bonded to a heteroaromatic ring, and the 3-position of the heteroaromatic ring is nitrogen. In General Formula (G1) shown above, a and b each independently represent a substituted or unsubstituted arylene group having 6 to 13 carbon atoms in a ring. In addition, m and n are each independently 0, 1, or 2.
Abstract:
A positive electrode active material in which a capacity decrease caused by charge and discharge cycles is suppressed is provided. Alternatively, a positive electrode active material having a crystal structure that is unlikely to be broken by repeated charging and discharging is provided. The positive electrode active material contains titanium, nickel, aluminum, magnesium, and fluorine, and includes a region where titanium is unevenly distributed, a region where nickel is unevenly distributed, and a region where magnesium is unevenly distributed in a projection on its surface. Aluminum is preferably unevenly distributed in a surface portion, not in the projection, of the positive electrode active material.
Abstract:
Provided is a layer for preventing a short circuit between a positive electrode and a negative electrode in a solid battery using a layer containing a solid electrolyte. As the solid electrolyte between the positive electrode and the negative electrode, a layer containing a graphene compound is used. Lithium ions can pass through the layer containing the graphene compound. Lithium ions are added in advance in the layer containing the graphene compound. Specifically, a modifier is used, and a graphene compound chemically modified with a functional group such as ether and ester with an increased interlayer distance is used.
Abstract:
A control system for a secondary battery which is less affected by the ambient temperature by performing temperature control of the secondary battery is provided. A control system for a secondary battery which is less affected by the ambient temperature and in which a plurality of kinds of secondary batteries are used for temperature control is achieved and mounted on a vehicle. Specifically, when the ambient temperature is low, some of second secondary batteries are heated by self-heating of a first secondary battery. After the second secondary batteries are sufficiently heated, the rest of the second secondary batteries are heated in stages by self-heating of the some of the second secondary batteries whose temperature has been increased. Whether the some or all of the second secondary batteries are sufficiently heated can be confirmed if the temperatures of a plurality of temperature sensors provided in the second secondary batteries are within the operating temperature range of the second secondary batteries. For example, with the use of a temperature sensing terminal (T terminal) for a temperature sensor, a switch is closed when the internal temperature of the secondary batteries is out of the operating temperature range.
Abstract:
An organic compound that easily exhibits thermally activated delayed fluorescence (TADF) is provided. An organic compound represented by General Formula (G1) is provided. In General Formula (G1), R1 to R8 are each independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted diarylamino group; at least one of R1 to R8 is a substituted or unsubstituted diarylamino group; a is a substituted or unsubstituted phenylene group; n is an integer of 0 to 4; and A represents a substituted or unsubstituted benzofuropyrimidine skeleton or benzothienopyrimidine skeleton.