Abstract: A negative-electrode active material comprises a graphite including boron and nitrogen. A ratio R1 satisfies 0.5?R1?1, where R1=SBN/SB, and SB denotes a total peak area of a boron 1s spectrum of the graphite obtained by X-ray photoelectron spectroscopy, and SBN denotes a peak area of a spectrum assigned to boron bonded to nitrogen in the boron 1s spectrum. A ratio R2 satisfies 0<R2?0.05, where R2=SB/(SB+SC+SN), and SC denotes a peak area of a carbon 1s spectrum of the graphite obtained by X-ray photoelectron spectroscopy, and SN denotes a peak area of a nitrogen 1s spectrum of the graphite obtained by X-ray photoelectron spectroscopy.

Abstract: A negative-electrode active material comprises: a graphite including boron; and a covering layer that covers a surface of the graphite. The covering layer comprises carbon. A ratio R satisfies 0?R?0.001, where R=SB/(SB+SC), and SB denotes a total peak area of a boron 1 s spectrum of the negative-electrode active material obtained by X-ray photoelectron spectroscopy, and SC denotes a total peak area of a carbon 1 s spectrum of the negative-electrode active material obtained by X-ray photoelectron spectroscopy.

Abstract: A nonaqueous electrolyte includes a nonaqueous solvent and an alkali metal salt dissolved in the nonaqueous solvent. The nonaqueous solvent contains a perfluoropolyether and a nitrile compound represented by a formula Rf—CN, where Rf represents a hydrocarbon group which has a carbon number of 2 to 4 and in which at least one hydrogen atom is substituted with fluorine.

Abstract: A nonaqueous electrolyte includes a nonaqueous solvent and an alkali metal salt dissolved in the nonaqueous solvent. The nonaqueous solvent contains a polar organic solvent, a perfluoropolyether, and a diester compound represented by a formula R1—O—C(?O)—[—(CF2)—]a—C(?O)—O—R2, where a is an integer of 1 to 4, and each of R1 and R2 represents one selected from the group consisting of an alkyl group having a carbon number of 1 to 4 and a hydrocarbon group which has a carbon number of 1 to 4 and in which at least one hydrogen atom is substituted with fluorine.

Abstract: Provided is an electrolytic solution including a nonaqueous solvent and an alkali metal salt. The alkali metal salt is dissolved in the nonaqueous solvent. The nonaqueous solvent contains a perfluoropolyether. The molecular ends of the perfluoropolyether are each an unsubstituted alkyl ether or an unsubstituted carboxylate. The perfluoropolyether has a repeating unit composed of a perfluoroalkyl chain and an oxygen atom. Also provided is a battery including the electrolytic solution, a positive electrode containing a positive electrode active material that can occlude and release an alkali metal cation, and a negative electrode containing a negative electrode active material that can occlude and release the alkali metal cation.

Abstract: A non-aqueous electrolytic solution of the present invention includes: a solvent component including a glyme solvent and a phosphazene solvent; and an alkali metal salt composed of an alkali metal cation and an anion, the alkali metal salt being dissolved in the solvent component. The phosphazene solvent is a cyclic phosphazene compound represented by the formula (1). where X1 to X6 each independently represent a halogen atom or OR1, R1 is a substituted or unsubstituted aromatic group or a substituted or unsubstituted saturated aliphatic group, the aromatic group and the saturated aliphatic group each optionally contain a halogen atom, a nitrogen atom, an oxygen atom, a sulfur atom, or a silicon atom, and the saturated aliphatic group is linear or cyclic.

Abstract: A power storage device of the present invention includes a positive electrode, a negative electrode, and an electrolyte. At least one of the positive electrode and the negative electrode includes an organic compound as an active material having a portion contributing to an oxidation-reduction reaction. The organic compound is crystalline in both a charged state and a discharged state.

Abstract: A battery includes a positive electrode including a positive electrode active material, a negative electrode, and an electrolytic solution including a nonaqueous solvent. The positive electrode active material includes a compound having a crystal structure belonging to a space group FM3-M and represented by Compositional Formula (1): LixMeyO?F?, where, Me is one or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and Cr; and subscripts x, y, ?, and ? satisfy the following requirements: 1.7?x?2.2, 0.8?y?1.3, 1???2.5, and 0.5???2. The nonaqueous solvent includes a solvent having at least one fluoro group.

Abstract: An electrolyte solution contains a non-aqueous solvent and an alkali metal salt dissolved in the non-aqueous solvent. The non-aqueous solvent contains cyclopropanecarbonitrile. A battery includes an electrolyte solution which contains a non-aqueous solvent containing cyclopropanecarbonitrile and an alkali metal salt dissolved in the non-aqueous solvent, a positive electrode containing a positive electrode active material that has a property of occluding and releasing an alkali metal ion, and a negative electrode containing an alkali metal or a negative electrode active material that has a property of occluding and releasing the alkali metal ion.

Abstract: A battery includes a positive electrode including a positive electrode active material, a negative electrode, and an electrolytic solution including an additive. The positive electrode active material includes a compound having a crystal structure belonging to a space group FM3-M and represented by Compositional Formula (1): LixMeyO?F?, where, Me is one or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and Cr; and subscripts x, y, ?, and ? satisfy the following requirements: 1.7?x?2.2, 0.8?y 1.3, 1???2.5, and 0.5???2. The additive is at least one selected from dinitrile compounds and diisocyanate compounds.

Abstract: Provided is an electrolytic solution including a nonaqueous solvent and an alkali metal salt. The alkali metal salt is dissolved in the nonaqueous solvent. The nonaqueous solvent contains a perfluoropolyether and a fluorinated phosphate. Also provided is a battery including the electrolytic solution, a positive electrode containing a positive electrode active material that can occlude and release an alkali metal cation, and a negative electrode containing a negative electrode active material that can occlude and release the alkali metal cation.

Abstract: A battery includes a positive electrode including a positive electrode active material, a negative electrode, and an electrolytic solution including a lithium hexafluorophosphate and an additive. The positive electrode active material includes a compound having a crystal structure belonging to a space group FM3-M and represented by Compositional Formula (1): LixMeyO?F?. The additive is at least one selected from the group consisting of difluorophosphates, tetrafluoroborates, bis(oxalate)borate salts, bis(trifluoromethanesulfonyl)imide salts, and bis(fluorosulfonyl)imide salts.

Abstract: Provided is a battery including: a positive electrode containing a positive electrode active material; a negative electrode; and an electrolyte solution containing a nonaqueous solvent. The positive electrode active material contains a compound represented by composition formula (1) below and having a crystal structure belonging to space group FM3-M: LixMeyO?F?. (1) Here, Me is one or two or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and C. x, y, ?, and ? satisfy the following conditions: 1.7?x?2.2, 0.8?y?1.3, 1???2.5, and 0.5???2, respectively. The nonaqueous solvent includes at least one solvent selected from hydrofluoroethers, phosphazenes, phosphates, and perfluoropolyethers.

Abstract: A negative electrode material includes a carbon material including boron. In a B1s spectrum of the carbon material which is measured by X-ray photoelectron spectroscopy, the ratio of the area of a peak that occurs at a binding energy of 187.0 eV or more and 188.5 eV or less to the total area of peaks that occur at a binding energy of 184.0 eV or more and 196.5 eV or less is 50% or more.

Abstract: A redox flow battery includes first and second electrodes, a separator separating the first and second electrodes, an active material, an electrolytic solution containing a redox species, and a circulation mechanism. The active material is insoluble in the electrolytic solution. The circulation mechanism circulates the electrolytic solution between the first electrode and the active material. The redox species performs oxidation and reduction at the first electrode and is oxidized and reduced by the active material. The circulation mechanism includes an electrolytic solution container containing the active material and a permeation preventing unit. The electrolytic solution is brought into contact with the active material in the electrolytic solution container, and the redox species is oxidized and reduced by the active material. The permeation preventing unit is disposed adjacent the outlet for the electrolytic solution of the electrolytic solution container and prevents permeation of the active material.

Abstract: A battery electrolyte comprises: a non-aqueous solvent including a perfluoropolyether that is functionalized at only one molecule end, the perfluoropolyether including perfluoroalkyl chains and oxygen atoms in such a manner that a perfluoroalkyl chain and an oxygen atom are alternately bound to each other; and a metal salt that is a magnesium salt, an alkaline earth metal salt, or an alkali metal salt, and that is dissolved in the non-aqueous solvent.

Abstract: A negative electrode active material includes a carbon material including boron and a silicon material including at least one selected from silicon and silicon oxide. The silicon material does not include boron. A peak of a B1s spectrum of the carbon material occurs at a binding energy of 187.0 eV or more and 192.0 eV or less, the B1s spectrum being measured by X-ray photoelectron spectroscopy. The ratio of the area of the peak of the B1s spectrum of the carbon material which occurs at a binding energy of 187.0 eV or more and 192.0 eV or less, the B1s spectrum being measured by X-ray photoelectron spectroscopy, to the total area of peaks of the B1s spectrum which occur at a binding energy of 184.0 eV or more and 196.5 eV or less is 50% or more.

Abstract: An electrochemical device includes a negative electrode containing a negative electrode active material, a positive electrode, and an electrolyte. The negative electrode active material has a crystal structure with an Fm3m space group and contains a compound represented by composition formula (1) below, LixTiyOz ??Formula (1), where 0.4?x/y<2 and x/2+3y/2?z?x/2+2y.

Abstract: A negative-electrode active material for a sodium-ion secondary battery contains a porous carbon material which has a plurality of open pores that extend through to the surface, a plurality of closed pores that do not extend through to the surface, and a solid made of carbon material. The distance between (002) planes of the solid portion is not less than 0.340 nm and not more than 0.410 nm. The plurality of closed pores account for a volume ratio of not less than 0% and not more than 10% with respect to a total volume of the plurality of open pores, the plurality of closed pores, and the solid portion. The plurality of open pores account for a volume ratio of not less than 0% and not more than 50% with respect to a total volume of the plurality of open pores, the plurality of closed pores, and the solid portion.

Abstract: An object of the present invention or a problem to be solved by the present invention is to provide, as a material for use as a positive electrode of a sodium secondary battery, a novel material that allows the resulting battery to have capacity characteristics superior to those of conventional batteries. The composite metal oxide of the present invention has a composition represented by the general formula NaxMeyO2, where Me is at least one selected from the group consisting of Fe, Mn, and Ni, x satisfies 0.8<x?1.0, and y satisfies 0.95?y<1.05, and consists of a P2 structure. The sodium secondary battery of the present invention includes: a positive electrode (13) containing the composite metal oxide of the present invention; a negative electrode (16) containing a material capable of absorbing and desorbing Na ions; and an electrolyte containing Na ions and anions.