Abstract: A nonaqueous electrolyte secondary battery including a negative electrode containing a graphite material as the negative active material, a positive electrode containing lithium cobalt oxide as a main component of the positive active material and a nonaqueous electrolyte solution, the battery being characterized in that the lithium cobalt oxide contains a group IVA element selected from the group consisting of Ti, Zr and Hf and a group IIA element of the periodic table, the nonaqueous electrolyte solution contains 0.2-1.5% by weight of a sulfonyl-containing compound and preferably further contains 0.5-4% by weight of vinylene carbonate.

Abstract: A nonaqueous electrolyte secondary battery in which a lithium transition metal complex oxide containing at least Ni and Mn as transition metals and having a layered structure is used as a positive active material, the lithium transition metal complex oxide containing at least Ni and Mn as transition metals and having a layered structure further containing zirconium.

Abstract: A nonaqueous electrolyte secondary battery which has a positive electrode containing lithium cobalt oxide as a positive active material, a negative electrode containing a graphite material and a nonaqueous electrolyte solution containing ethylene carbonate as a solvent and which is charged with an end-of-charge voltage of at least 4.3 V. Characteristically, the battery uses, as the positive active material, lithium cobalt oxide obtained by firing a mixture of a lithium salt, tricobalt tetraoxide (Co3O4) and a zirconium compound and having particle surfaces onto which the zirconium compound adheres.

Abstract: Capacity degradation due to charge/discharge cycles is suppressed in either a non-aqueous electrolyte secondary cell provided with a positive electrode including, as a positive electrode active material, a lithium-transition metal complex oxide having a layered structure and containing at least Ni and Mn as transition metals, and a negative electrode containing a carbon material as a negative electrode active material and having a higher initial charge-discharge efficiency than that of the positive electrode, or an assembled battery having a plurality of cells each of which is the secondary cell. A control circuit incorporated in the secondary cell or the assembled battery, or in an apparatus using the secondary cell or the assembled battery, monitors the voltage of the secondary cell or each of the cells in the assembled battery so that the end-of-discharge voltage of each cell is 2.9 V or higher.

Abstract: A nonaqueous electrolyte secondary battery includes a positive electrode containing a positive active material, a negative electrode containing a negative active material and a nonaqueous electrolyte. Characteristically, the positive active material comprises a mixture of a lithium transition metal complex oxide A obtained by incorporating at least Zr and Mg into LiCoO2 and a lithium transition metal complex oxide B having a layered structure and containing at least Ni and Mn as the transition metal.

Abstract: A nonaqueous electrolyte secondary battery including a negative electrode containing a graphite material as the negative active material, a positive electrode containing lithium cobalt oxide as a main component of the positive active material and a nonaqueous electrolyte solution, the battery being characterized in that the lithium cobalt oxide contains a group IVA element selected from the group consisting of Ti, Zr and Hf and a group IIA element of the periodic table, the nonaqueous electrolyte solution contains 0.2-1.5% by weight of a sulfonyl-containing compound and preferably further contains 0.5-4% by weight of vinylene carbonate.

Abstract: A nonaqueous electrolyte secondary battery including a negative electrode containing a graphite material as the negative active material, a positive electrode containing lithium cobalt oxide as a main component of the positive active material and a nonaqueous electrolyte solution, the battery being characterized in that the lithium cobalt oxide contains a group IVA element and a group IIA element of the periodic table, the nonaqueous electrolyte solution contains 0.2-1.5% by weight of a sulfonyl-containing compound and preferably further contains 0.5-4% by weight of vinylene carbonate.

Abstract: A nonaqueous electrolyte secondary battery includes a positive electrode containing a positive active material, a negative electrode containing a negative active material and a nonaqueous electrolyte. Characteristically, the positive active material comprises a mixture of a lithium transition metal complex oxide A obtained by incorporating at least Zr and Mg into LiCoO2 and a lithium transition metal complex oxide B having a layered structure and containing at least Ni and Mn as the transition metal.

Abstract: A nonaqueous electrolyte secondary battery includes a positive electrode containing a positive active material, a negative electrode containing a negative active material and a nonaqueous electrolyte. Characteristically, the positive active material comprises a mixture of a lithium transition metal complex oxide A obtained by incorporating at least Zr and Mg into LiCoO2 and a lithium transition metal complex oxide B having a layered structure and containing at least Ni and Mn as the transition metal.

Abstract: Method of increasing charge-discharge capacity of a nonaqueous electrolyte secondary battery including a positive electrode containing a positive active material, a negative electrode containing a negative active material other than metallic lithium and a nonaqueous electrolyte. The battery is charged at an end-of-charge voltage of at least 4.3V. The positive active material includes lithium cobaltate in which Zr and Mg are contained by mixing their source materials in the preparation of the positive active material by a heat treatment, the Zr and Mg being contained in the lithium cobaltate in a total amount of not greater than 3 mole %, the Zr after heat treatment being present as particles of a Zr-containing compound that are sintered with particle surfaces of the lithium cobaltate, and the Zr being detected in the particles of the Zr-containing compound but not in the lithium cobaltate particles.

Abstract: A nonaqueous electrolyte secondary battery wherein a material capable of occluding/discharging lithium is used as a negative electrode material and a lithium-transition metal composite oxide which contains Ni and Mn as the transition metal and has a layered structure is used as a positive electrode material is characterized in that a lithium-transition metal composite oxide having a BET specific surface area less than 3 m2/g and a pH of 11.0 or less when 5 g of the lithium-transition metal composite oxide is immersed in 50 ml of purified water is used as the positive electrode active material.

Abstract: A non-aqueous electrolyte secondary battery comprises: a positive electrode using a positive electrode active material consisting of metal composite oxide containing lithium having a laminated structure; a negative electrode; and a non-aqueous electrolyte dissolving an electrolyte in a non-aqueous solvent; wherein the positive electrode active material contains 50 mol % or more of nickel in metal excluding lithium, and cyclic ether is added in the range of 0.1 volume % to 2.0 volume % to the non-aqueous electrolyte.

Abstract: A nonaqueous electrolyte secondary battery including a positive electrode containing a positive active material, a negative electrode containing a negative active material and a nonaqueous electrolyte. The secondary battery contains, as the negative active material, a lithium-containing molybdenum oxide represented by a chemical formula LixMoO2 (0.05?x?0.25) when in a fully discharged state. The lithium-containing molybdenum oxide can be obtained by allowing lithium to react to molybdenum dioxide (MoO2) electrochemically, for example.

Abstract: A nonaqueous electrolyte secondary battery includes a positive electrode containing a positive active material, a negative electrode containing a negative active material and a nonaqueous electrolyte. Characteristically, the positive active material comprises a mixture of a lithium transition metal complex oxide A obtained by incorporating at least Zr and Mg into LiCoO2 and a lithium transition metal complex oxide B having a layered structure and containing at least Ni and Mn as the transition metal.

Abstract: A nonaqueous electrolyte secondary battery in which a lithium transition metal complex oxide containing at least Ni and Mn as transition metals and having a layered structure is used as a positive active material, the lithium transition metal complex oxide containing at least Ni and Mn as transition metals and having a layered structure further containing zirconium.

Abstract: A nonaqueous electrolyte secondary battery which has a positive electrode containing lithium cobalt oxide as a positive active material, a negative electrode containing a graphite material and a nonaqueous electrolyte solution containing ethylene carbonate as a solvent and which is charged with an end-of-charge voltage of at least 4.3 V. Characteristically, the battery uses, as the positive active material, lithium cobalt oxide obtained by firing a mixture of a lithium salt, tricobalt tetraoxide (Co3O4) and a zirconium compound and having particle surfaces onto which the zirconium compound adheres.

Abstract: A nonaqueous electrolyte secondary battery including a negative electrode containing a graphite material as the negative active material, a positive electrode containing lithium cobalt oxide as a main component of the positive active material and a nonaqueous electrolyte solution, the battery being characterized in that the lithium cobalt oxide contains a group IVA element and a group IIA element of the periodic table, the nonaqueous electrolyte solution contains 0.2-1.5% by weight of a sulfonyl-containing compound and preferably further contains 0.5-4% by weight of vinylene carbonate.

Abstract: A nonaqueous electrolyte secondary battery wherein a material capable of occludeing/discharging lithium is used as a negative electrode material and a lithium-trasition metal composite oxide which contains Ni and Mn as the transition metal and has a layered structure is used as a positive electrode material is characterized in that a lithium-transition metal composite oxide having a BET specific surface area less than 3 m2/g and a pH of 11.0 or less when 5 g of the lithium-transition metal composite oxide is immersed in 50 ml of purified water is used as the positive electrode active material.

Abstract: A nonaqueous electrolyte secondary battery according to the invention comprises a positive electrode containing a positive electrode active material including lithium containing composite oxide having a layer crystal structure represented by a general formula of LixMnaCobMcO2 (0.9?X?1.1, 0.45?a?0.55, 0.45?b?0.55, 0<c?0.05 and 0.9<a+b+c?1.1 are set and M is at least one kind selected from Al, Mg, Sn, Ti and Zr), a negative electrode containing a negative electrode active material capable of intercalating and deintercalating lithium ion, a separator for separating the positive electrode from the negative electrode, and a nonacqueous electrolyte.

Abstract: A lithium secondary battery employing as its negative electrode active material a material that increases in volume by alloying with lithium during charge achieves high discharge capacity and good cycle performance. The lithium secondary battery includes a negative electrode having a negative electrode active material (2) and a negative electrode current collector, a positive electrode having a positive electrode active material (1) and a positive electrode current collector (3), and a non-aqueous electrolyte. The negative electrode active material (2) is a material that increases in volume by alloying with lithium during charge. The negative electrode active material (1) is arranged so as to be on, and in contact with, the negative electrode current collector. The negative electrode active material (2) contains, when in an end-of-discharge condition, 8% or more of lithium with respect to the total capacity of the negative electrode active material (2) as measured when it does not contain lithium.