Abstract: A lithium ion secondary battery includes a positive electrode containing a spinel-type lithium-nickel-manganese composite oxide as a positive electrode active material; a negative electrode containing, as a negative electrode active material, an active material in which introduction and release of lithium ions take place at a potential of 1.2 V or higher relative to a lithium potential; a separator inserted between the positive electrode and the negative electrode; and an electrolytic solution, wherein a capacity ratio of a negative electrode capacity of the negative electrode to a positive electrode capacity of the positive electrode (negative electrode capacity/positive electrode capacity) is 1 or lower, and the electrolytic solution contains dimethyl carbonate as a non-aqueous solvent at a content ratio of higher than 70% by volume with respect to a total amount of the non-aqueous solvent.

Abstract: Provided is an electrolyte composition, comprising one or two or more polymers, oxide particles, at least one electrolyte salt selected from the group consisting of a lithium salt, a sodium salt, a calcium salt, and a magnesium salt, and a solvent, wherein structural units constituting the one or two or more polymers comprises a first structural unit selected from the group consisting of tetrafluoroethylene and vinylidene fluoride, and a second structural unit selected from the group consisting of hexafluoropropylene, acrylic acid, maleic acid, ethyl methacrylate, and methyl methacrylate, a content of the one or two or more polymers is more than 90% by mass based on a total amount of polymers in the electrolyte composition, and a mass ratio of a content of the first structural unit to a content of the second structural unit in the one or two or more polymers is 50/50 or more.

Abstract: The present invention provides a battery member for a secondary battery provided with a current collector, an electrode mixture layer disposed on the current collector, an electrolyte layer disposed on the electrode mixture layer in this order, wherein the electrode mixture layer comprises an electrode active material and an ionic liquid, and the porosity of the electrode mixture layer is 10% by volume or less relative to the volume of the electrode mixture layer.

Abstract: A lithium-ion secondary battery contains: a positive electrode that contains a positive electrode active material including a lithium nickel manganese complex oxide having a spinel structure, and contains an electroconductive agent including a non-crystalline carbon and graphite; and a negative electrode that contains a negative electrode active material in which lithium ions are inserted and eliminated at an electric potential of 1.2 V or more with respect to an electric potential of lithium.

Abstract: A lithium-ion battery includes: a cathode; an anode; and a non-aqueous electrolyte solution, in which the cathode includes a current collector and a cathode mixture applied on at least one side of the current collector, the cathode mixture includes a lithium transition metal oxide as a cathode active material, the anode includes a lithium titanium complex oxide as an anode active material, and the non-aqueous electrolyte solution includes a fluorine-containing boric acid ester.

Abstract: A method for charging a lithium-ion secondary battery, comprising: charging a lithium-ion secondary battery by performing constant-current charge until a set voltage is reached, or by performing constant-current charge until a set voltage is reached followed by performing constant-voltage charge at the set voltage for 30 minutes or less, the lithium-ion secondary battery comprising: a positive electrode comprising a positive electrode active material comprising a spinel-type lithium nickel manganese complex oxide; a negative electrode; and an electrolytic solution comprising a nonaqueous solvent comprising dimethyl carbonate, wherein a content of the dimethyl carbonate is more than 70% by volume with respect to a total amount of the nonaqueous solvent, and a capacity ratio between a negative electrode capacity of the negative electrode and a positive electrode capacity of the positive electrode (negative electrode capacity/positive electrode capacity) is 1 or less, is provided.

Abstract: A lithium-ion secondary battery contains: a positive electrode including a lithium nickel manganese complex oxide as a positive electrode active material; a negative electrode; and an electrolyte solution; in which the electrolyte solution includes dimethyl carbonate as a nonaqueous solvent, and an end-of-charge voltage is in a range from 3.4 V to 3.8 V and an end-of-discharge voltage is in a range from 2.0 V to 2.8 V.

Abstract: A lithium ion secondary battery includes a positive electrode containing a spinel-type lithium-nickel-manganese composite oxide as a positive electrode active material; a negative electrode containing, as a negative electrode active material, an active material in which introduction and release of lithium ions take place at a potential of 1.2 V or higher relative to a lithium potential; a separator inserted between the positive electrode and the negative electrode; and an electrolytic solution, wherein a capacity ratio of a negative electrode capacity of the negative electrode to a positive electrode capacity of the positive electrode (negative electrode capacity/positive electrode capacity) is 1 or lower, and the electrolytic solution contains dimethyl carbonate as a non-aqueous solvent at a content ratio of higher than 70% by volume with respect to a total amount of the non-aqueous solvent.

Abstract: A lithium-ion battery includes: a cathode; an anode; and a non-aqueous electrolyte solution, in which the cathode includes a current collector and a cathode mixture applied on at least one side of the current collector, the cathode mixture includes a lithium transition metal oxide as a cathode active material, the anode includes a lithium titanium complex oxide as an anode active material, and the non-aqueous electrolyte solution includes a fluorine-containing boric acid ester.