Abstract: A mixture of amorphous PAHs and at least one of a carrier ion storage metal, a Sn compound, a carrier ion storage alloy, a metal compound, Si, Sb, and SiO2 is used as the negative electrode active material. The theoretical capacity of amorphous PAHs greatly exceeds that of a graphite based carbon material. Thus, the use of amorphous PAHs enables the negative electrode active material to have a higher capacity than in the case of using the graphite-based carbon material. Further, addition of at least one of the carrier ion storage metal, the Sn compound, the carrier ion storage alloy, the metal compound, Si, Sb, and SiO2 to the amorphous PAHs enables the negative electrode active material to have a higher capacity than the case of only using the amorphous PAHs.

Abstract: A nonaqueous electrolyte of the present invention includes an ionic liquid including a first alicyclic quaternary ammonium cation having one or more substituents, a second alicyclic quaternary ammonium cation having an alicyclic skeleton that is the same as an alicyclic skeleton of the first alicyclic quaternary ammonium cation, and a counter anion to the first alicyclic quaternary ammonium cation and the second alicyclic quaternary ammonium cation and an alkali metal salt. In the second alicyclic quaternary ammonium cation, one of substituents bonded to a nitrogen atom in the alicyclic skeleton is a substituent including a halogen element. In the ionic liquid, the amount of a salt including the second alicyclic quaternary ammonium cation is less than or equal to 1 wt % per unit weight of the ionic liquid, or is less than or equal to 0.8 wt % per unit weight of the nonaqueous electrolyte.

Abstract: A mixture of amorphous PAHs and at least one of a carrier ion storage metal, a Sn compound, a carrier ion storage alloy, a metal compound, Si, Sb, and SiO2 is used as the negative electrode active material. The theoretical capacity of amorphous PAHs greatly exceeds that of a graphite based carbon material. Thus, the use of amorphous PAHs enables the negative electrode active material to have a higher capacity than in the case of using the graphite-based carbon material. Further, addition of at least one of the carrier ion storage metal, the Sn compound, the carrier ion storage alloy, the metal compound, Si, Sb, and SiO2 to the amorphous PAHs enables the negative electrode active material to have a higher capacity than the case of only using the amorphous PAHs.

Abstract: A mixture of amorphous PAHs and at least one of a carrier ion storage metal, a Sn compound, a carrier ion storage alloy, a metal compound, Si, Sb, and SiO2 is used as the negative electrode active material. The theoretical capacity of amorphous PAHs greatly exceeds that of a graphite-based carbon material. Thus, the use of amorphous PAHs enables the negative electrode active material to have a higher capacity than in the case of using the graphite-based carbon material. Further, addition of at least one of the carrier ion storage metal, the Sn compound, the carrier ion storage alloy, the metal compound, Si, Sb, and SiO2 to the amorphous PAHs enables the negative electrode active material to have a higher capacity than the case of only using the amorphous PAHs.

Abstract: A power storage device with high capacity, a power storage device with high energy density, a highly reliable power storage device, and a long-life power storage device are provided. The power storage device includes a positive electrode, a separator, a negative electrode, and an electrolytic solution. The electrolytic solution contains an alkali metal salt and an ionic liquid. The separator is located between the positive electrode and the negative electrode. At least part of the positive electrode overlaps with the negative electrode. At least part of an end portion of the negative electrode is located inside a region between end portions of the positive electrode.

Abstract: A power storage device with reduced initial irreversible capacity is provided. The power storage device includes a positive electrode including 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 solution. In the negative electrode active material layer, the content percentage of a carbon material with an R value of 1.1 or more is less than 2 wt %. The R value refers to a ratio of a peak intensity I1360 to a peak intensity I1580 (I1360/I1580). The peak intensity I1360 and the peak intensity I1580 are observed by Raman spectrometry at a Raman shift of 1360 cm?1 and a Raman shift of 1580 cm?1, respectively. The electrolyte solution contains a lithium ion and an ionic liquid composed of an organic cation and an anion.

Abstract: To provide an ionic liquid which has at least one of properties such as high ionic conductivity, a small reduction in ionic conductivity at a low temperature, a low melting point, and a low viscosity. To provide a power storage device having higher initial charge and discharge efficiency than a power storage device containing a conventional ionic liquid. A cyclic quaternary ammonium salt is liquid at room temperature and contains a quaternary spiro ammonium cation having an asymmetrical structure including two aliphatic rings and one or more substituents bonded to one or both of the two aliphatic rings and an anion corresponding to the quaternary spiro ammonium cation. The power storage device includes a positive electrode, a negative electrode, and a nonaqueous electrolyte containing the cyclic quaternary ammonium salt as a nonaqueous solvent.

Abstract: A power storage device with reduced initial irreversible capacity is provided. The power storage device includes a positive electrode including 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 solution. In the negative electrode active material layer, the content percentage of a carbon material with an R value of 1.1 or more is less than 2 wt %. The R value refers to a ratio of a peak intensity I1360 to a peak intensity I1580 (I1360/I1580). The peak intensity I1360 and the peak intensity I1580 are observed by Raman spectrometry at a Raman shift of 1360 cm?1 and a Raman shift of 1580 cm?1, respectively. The electrolyte solution contains a lithium ion and an ionic liquid composed of an organic cation and an anion.

Abstract: A power storage device with reduced initial irreversible capacity is provided. The power storage device includes a positive electrode including 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 solution. In the negative electrode active material layer, the content percentage of a carbon material with an R value of 1.1 or more is less than 2 wt %. The R value refers to a ratio of a peak intensity I1360 to a peak intensity I1580 (I1360/I1580). The peak intensity I1360 and the peak intensity I1580 are observed by Raman spectrometry at a Raman shift of 1360 cm?1 and a Raman shift of 1580 cm?1, respectively. The electrolyte solution contains a lithium ion and an ionic liquid composed of an organic cation and an anion.

Abstract: A power storage device with reduced initial irreversible capacity is provided. The power storage device includes a positive electrode including 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 solution, in the negative electrode active material layer, the content percentage of a carbon material with an R value of 1.1 or more is less than 2 wt %, The R value refers to a ratio of a peak intensity I1360 to a peak intensity I1580 (I1360/I1580). The peak intensity I1360 and the peak intensity I1580 are observed by Raman spectrometry at a Raman shift of 1360 cm?1 and a Raman shift of 1580 cm?1, respectively. The electrolyte solution contains a lithium ion and an ionic liquid composed of an organic cation and an anion.

Abstract: A power storage device with reduced initial irreversible capacity is provided. The power storage device includes a positive electrode including 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 solution. In the negative electrode active material layer, the content percentage of a carbon material with an R value of 1.1 or more is less than 2 wt %. The R value refers to a ratio of a peak intensity I1360 to a peak intensity I1580 (I1360/I1580). The peak intensity I1360 and the peak intensity I1580 are observed by Raman spectrometry at a Raman shift of 1360 cm?1 and a Raman shift of 1580 cm?1, respectively. The electrolyte solution contains a lithium ion and an ionic liquid composed of an organic cation and an anion.

Abstract: A power storage device with reduced initial irreversible capacity is provided. The power storage device includes a positive electrode including 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 solution. In the negative electrode active material layer, the content percentage of a carbon material with an R value of 1.1 or more is less than 2 wt %. The R value refers to a ratio of a peak intensity I1360 to a peak intensity I1580 (I1360/I1580). The peak intensity I1360 and the peak intensity I1580 are observed by Raman spectrometry at a Raman shift of 1360 cm?1 and a Raman shift of 1580 cm?1, respectively. The electrolyte solution contains a lithium ion and an ionic liquid composed of an organic cation and an anion.

Abstract: A power storage device with reduced initial irreversible capacity is provided. The power storage device includes a positive electrode including 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 solution. In the negative electrode active material layer, the content percentage of a carbon material with an R value of 1.1 or more is less than 2 wt %. The R value refers to a ratio of a peak intensity I1360 to a peak intensity I1580 (I1360/I1580). The peak intensity I1360 and the peak intensity I1580 are observed by Raman spectrometry at a Raman shift of 1360 cm?1 and a Raman shift of 1580 cm?1, respectively. The electrolyte solution contains a lithium ion and an ionic liquid composed of an organic cation and an anion.

Abstract: A nonaqueous electrolyte of the present invention includes an ionic liquid including a first alicyclic quaternary ammonium cation having one or more substituents, a second alicyclic quaternary ammonium cation having an alicyclic skeleton that is the same as an alicyclic skeleton of the first alicyclic quaternary ammonium cation, and a counter anion to the first alicyclic quaternary ammonium cation and the second alicyclic quaternary ammonium cation and an alkali metal salt. In the second alicyclic quaternary ammonium cation, one of substituents bonded to a nitrogen atom in the alicyclic skeleton is a substituent including a halogen element. In the ionic liquid, the amount of a salt including the second alicyclic quaternary ammonium cation is less than or equal to 1 wt % per unit weight of the ionic liquid, or is less than or equal to 0.8 wt % per unit weight of the nonaqueous electrolyte.

Abstract: A mixture of amorphous PAHs and at least one of a carrier ion storage metal, a Sn compound, a carrier ion storage alloy, a metal compound, Si, Sb, and SiO2 is used as the negative electrode active material. The theoretical capacity of amorphous PAHs greatly exceeds that of a graphite-based carbon material. Thus, the use of amorphous PAHs enables the negative electrode active material to have a higher capacity than in the case of using the graphite-based carbon material. Further, addition of at least one of the carrier ion storage metal, the Sn compound, the carrier ion storage alloy, the metal compound, Si, Sb, and SiO2 to the amorphous PAHs enables the negative electrode active material to have a higher capacity than the case of only using the amorphous PAHs.

Abstract: A nonaqueous electrolyte of the present invention includes an ionic liquid including a first alicyclic quaternary ammonium cation having one or more substituents, a second alicyclic quaternary ammonium cation having an alicyclic skeleton that is the same as an alicyclic skeleton of the first alicyclic quaternary ammonium cation, and a counter anion to the first alicyclic quaternary ammonium cation and the second alicyclic quaternary ammonium cation and an alkali metal salt. In the second alicyclic quaternary ammonium cation, one of substituents bonded to a nitrogen atom in the alicyclic skeleton is a substituent including a halogen element. In the ionic liquid, the amount of a salt including the second alicyclic quaternary ammonium cation is less than or equal to 1 wt % per unit weight of the ionic liquid, or is less than or equal to 0.8 wt % per unit weight of the nonaqueous electrolyte.

Abstract: A power storage device with high capacity, a power storage device with high energy density, a highly reliable power storage device, and a long-life power storage device are provided. The power storage device includes a positive electrode, a separator, a negative electrode, and an electrolytic solution. The electrolytic solution contains an alkali metal salt and an ionic liquid. The separator is located between the positive electrode and the negative electrode. At least part of the positive electrode overlaps with the negative electrode. At least part of an end portion of the negative electrode is located inside a region between end portions of the positive electrode.

Abstract: Provided are a nonaqueous solvent containing a compound with high conductivity and low viscosity and a high-performance power storage device using the nonaqueous solvent. The power storage device includes an ionic liquid. The ionic liquid contains an anion and a cation having a five-membered heteroaromatic ring having one or more substituents. At least one of the substituents is a straight chain formed of four or more atoms and includes one or more of C, O, Si, N, S, and P.

Abstract: A power storage device with reduced initial irreversible capacity is provided. The power storage device includes a positive electrode, a negative electrode, and an electrolyte solution. The negative electrode includes a negative electrode active material and a water-soluble polymer. The electrolyte solution includes an ionic liquid. The ionic liquid includes a cation and a monovalent amide anion.

Abstract: A nonaqueous solvent that includes an ionic liquid and has at least one of the following characteristics: high lithium ion conductivity, high lithium ion conductivity in a low temperature environment, high heat resistance, a wide available temperature range, a low freezing point (melting point), low viscosity, and the like. The nonaqueous solvent includes an ionic liquid and a fluorinated solvent. The ionic liquid contains an alicyclic quaternary ammonium cation which has a substituent and a counter anion to the alicyclic quaternary ammonium cation which has the substituent.