Abstract: A nonaqueous electrolyte secondary battery is obtained which shows good cycle characteristics even when charged to a high voltage. The nonaqueous electrolyte secondary battery has a positive electrode containing a positive active material, a negative electrode containing a negative active material and a nonaqueous electrolyte, wherein a lithium-containing transition metal oxide having a layered structure is contained in the positive electrode as the positive active material, an additive which is reductively decomposed in the range of +3.0-1.3 V versus metallic lithium is contained in the nonaqueous electrolyte, and the battery after assembled is overdischarged until a potential of the positive electrode falls down to a reductive potential of the additive or below.

Abstract: A lithium secondary battery including a positive electrode, a negative electrode including a carbon material as an active material, and a nonaqueous electrolyte comprising a solute dissolved in a nonaqueous solvent in which ?-butyrolactone is the main solvent, wherein the carbon material has a ratio (ID/IG) of a Raman spectrum intensity (a peak intensity ratio) (R) obtained by Raman spectroscopy of 0.2 or greater, and the nonaqueous electrolyte includes at least 0.1 part by weight of vinylene carbonate and at least 0.1 part by weight of vinyl ethylene carbonate in 100 parts by weight of the nonaqueous electrolyte.

Abstract: Cycle performance is improved without degrading initial efficiency of a non-aqueous electrolyte secondary battery that includes a positive electrode, a negative electrode, a non-aqueous electrolyte containing a solute and a solvent, the positive electrode including a positive electrode active material made of a lithium-containing transition metal oxide that contains lithium and cobalt and has a layered structure. The lithium-containing transition metal oxide is at least partially covered with a surface-treatment layer containing a phosphate compound represented by the chemical formula M1POk, where M1 is at least one element that can have a valency of 3 and k is an integer in a range of 2 to 4, and the lithium-containing transition metal oxide contains a group IVA element M2 and a group IIA element M3 of the periodic table.

Abstract: A nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode comprising a graphite as a negative electrode active material, and a nonaqueous electrolyte including at least a saturated cyclic carbonic ester and containing a cyclic carbonic ester having a carbon-carbon double bond such that, when a content of the cyclic carbonic ester having a carbon-carbon double bond is x (g), a content of the graphite in the negative electrode is B (g), a specific surface area of the graphite is A (m2/g), a size of the crystallite of the graphite in a direction of the c axis is Lc, and a size of the crystallite of the graphite in a direction of the a axis is La, a condition expressed by 0.05×10?2?x/[A×B×2Lc/(2Lc+La)]?3×10?2 is satisfied.

Abstract: In a non-aqueous electrolyte secondary battery provided with a positive electrode, a negative electrode, and a non-aqueous electrolyte solution, a positive electrode active material is a mixture of lithium-manganese composite oxide and at least one of lithium-nickel composite oxide represented by a general formula LiNiaM11?aO2 and lithium-cobalt composite oxide represented by the general formula LiCobM21?bO2, and said non-aqueous electrolyte solution contains at least a saturated cyclic carbonic acid ester and an unsaturated cyclic carbonic acid ester having double bond of carbon where content by amount of said unsaturated cyclic carbonic acid ester having double bond of carbon is in a range of 1.0×10?8 to 2.4×10?4 g per positive electrode capacity 1 mAh.

Abstract: In a non-aqueous electrolyte secondary battery provided with a positive electrode, a negative electrode using carbon material as negative electrode active material, and a non-aqueous electrolyte solution, the non-aqueous electrolyte solution contains at least a saturated cyclic carbonic ester and a cyclic carbonic ester having C?C double bond where an amount of the cyclic carbonic ester having C?C double bond is in a range of 1.0×10?8 to 13.0×10?5 g per negative electrode capacity of 1 mAh.

Abstract: Charge-discharge characteristics are improved in a non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode, and a non-aqueous electrolyte containing a phosphoric ester compound as a solvent. In a non-aqueous electrolyte for secondary batteries containing a phosphoric ester compound, a lithium salt having an oxalato complex as an anion is contained as a solute. Preferably, the non-aqueous electrolyte contains lithium bis(oxalato)borate at a concentration of 0.01 to 0.2 mol/L with respect to the solvent, and more preferably, the non-aqueous electrolyte also contains vinylene carbonate.

Abstract: Cycle performance is improved without degrading initial efficiency of a non-aqueous electrolyte secondary battery that includes a positive electrode, a negative electrode, a non-aqueous electrolyte containing a solute and a solvent, the positive electrode including a positive electrode active material made of a lithium-containing transition metal oxide that contains lithium and cobalt and has a layered structure. The lithium-containing transition metal oxide is at least partially covered with a surface-treatment layer containing a phosphate compound represented by the chemical formula M1POk, where M1 is at least one element that can have a valency of 3 and k is an integer in a range of 2 to 4, and the lithium-containing transition metal oxide contains a group IVA element M2 and a group IIA element M3 of the periodic table.

Abstract: For us in nonaqueous electrolyte secondary cells, the invention provides an electrode which comprises a first carbon material serving as a core material, and a second carbon material coating the first carbon material over the surface thereof and containing boron. When used as an active substance for negative electrode to provide a nonaqueous electrolyte secondary cell, the electrode diminishes the reduction of the cell capacity that would result if the cell is allowed to store, giving improved storage characteristics to the cell.

Abstract: Storage performance in a charged state is improved in a non-aqueous electrolyte battery that contains 10 volume % or more of ?-butyrolactone, which is highly safe and reliable, as a solvent. A non-aqueous electrolyte secondary battery has a positive electrode containing a positive electrode active material composed of a lithium-containing transition metal oxide containing lithium and cobalt, a negative electrode, and a non-aqueous electrolyte solution composed of a solute and a solvent. The solvent contains 10 volume % or more of ?-butyrolactone with respect to the total solvent, and the positive electrode active material contains a Group IVA element and a Group IIA element of the periodic table.

Abstract: A lithium secondary battery including a positive electrode, a negative electrode including a carbon material as an active material, and a nonaqueous electrolyte comprising a solute dissolved in a nonaqueous solvent in which &ggr;-butyrolactone is the main solvent, wherein the carbon material has a ratio (ID/IG) of a Raman spectrum intensity (a peak intensity ratio) (R) obtained by Raman spectroscopy of 0.2 or greater, and the nonaqueous electrolyte includes at least 0.1 part by weight of vinylene carbonate and at least 0.1 part by weight of vinyl ethylene carbonate in 100 parts by weight of the nonaqueous electrolyte.

Abstract: A lithium cell includes a positive electrode, a negative electrode employing a carbon material as an active material, and a non-aqueous electrolyte including a solute dissolved in a non-aqueous solvent, and is characterized in that the carbon material in the negative electrode has an RA value (IA/IG) of 0.05 or more, the RA value calculated from a peak intensity (IA) of a broad peak PA having a full width at half maximum of 100 cm−1 or more and a peak intensity (IG) in the vicinity of 1580 cm−1 as determined by laser Raman spectroscopy using an argon ion laser having a wavelength of 514.5 nm, the peak intensity (IA) determined from a peak PD in the vicinity of 1360 cm−1, as determined by the aforesaid laser Raman spectroscopy, which is separated into the broad peak PA having the full width at half maximum of 100 cm−1 or more and a peak PB having a full width at half maximum of less than 100 cm−1.

Abstract: A nonaqueous electrolyte secondary battery including a positive electrode containing a positive electrode active material, a negative electrode containing a carbon material as a negative electrode active material, and a nonaqueous electrolyte containing a solvent and a solute wherein sulfolane is included in the nonaqueous electrolyte as a solvent and vinyl ethylene carbonate and vinylene carbonate or a derivative of the vinylene carbonate are added to the nonaqueous electrolyte.

Abstract: In a non-aqueous electrolyte secondary battery provided with a positive electrode, a negative electrode, and a non-aqueous electrolyte solution, a positive electrode active material is a mixture of lithium-manganese composite oxide and at least one of lithium-nickel composite oxide represented by a general formula LiNiaM11−aO2 and lithium-cobalt composite oxide represented by the general formula LiCobM21−bO2, and said non-aqueous electrolyte solution contains at least a saturated cyclic carbonic acid ester and an unsaturated cyclic carbonic acid ester having double bond of carbon where content by amount of said unsaturated cyclic carbonic acid ester having double bond of carbon is in a range of 1.0×10−8 to 2.4×10−4 g per positive electrode capacity 1 mAh.

Abstract: In a non-aqueous electrolyte secondary battery provided with a positive electrode, a negative electrode using carbon material as negative electrode active material, and a non-aqueous electrolyte solution, the non-aqueous electrolyte solution contains at least a saturated cyclic carbonic ester and a cyclic carbonic ester having C═C double bond where an amount of the cyclic carbonic ester having C═C double bond is in a range of 1.0×10−8 to 13.0×10−5 g per negative electrode capacity of 1 mAh.

Abstract: A nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode comprising a graphite as a negative electrode active material, and a nonaqueous electrolyte including at least a saturated cyclic carbonic ester and containing a cyclic carbonic ester having a carbon-carbon double bond such that, when a content of the cyclic carbonic ester having a carbon-carbon double bond is x (g), a content of the graphite in the negative electrode is B (g), a specific surface area of the graphite is A (m2/g), a size of the crystallite of the graphite in a direction of the c axis is Lc, and a size of the crystallite of the graphite in a direction of the a axis is La, a condition expressed by

Abstract: A nonaqueous electrolyte secondary battery having a positive electrode including a positive electrode active material, a negative electrode and a nonaqueous electrolyte comprising a solute dissolved in a solvent, the positive electrode active material is a mixture of a lithium-manganese composite oxide and a lithium-nickel composite oxide represented by LiNiaM11- aO2 (M1 being at least one element selected from the group consisting of B, Mg, Al, Ti, Mn, V, Fe, Co, Cu, Zn, Ga, Y, Zr, Nb, Mo and In, and a being 0<a≦1) and/or a lithium-cobalt composite oxide represented by LiCobM21- bO2 (M2 being at least one element selected from the group consisting of B, Mg, Al, Ti, Mn, V, Fe, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo and In, and being 0<b≦1), and the nonaqueous electrolyte contains a phosphoric ester and an ether or an ester having a halogen substituted phenyl.

Abstract: A lithium secondary battery according to the present invention includes a positive electrode in which an aluminum foil containing manganese is used as a current collector, a negative electrode, and a non-aqueous electrolyte solution formed by dissolving lithium salt in a non-aqueous solvent wherein divalent manganese salt is added to said non-aqueous electrolyte solution.

Abstract: The lithium secondary battery of this invention uses a nonaqueous electrolyte including lithium tetrakis(pentafluorophenyl)borate as a part or whole of an electrolytic salt. As a result, the lithium secondary battery exhibits better charge-discharge cycle performance than a lithium secondary battery using a conventional lithium salt as the electrolytic salt.

Abstract: A nonaqueous electrolyte secondary cell having a rolled-up electrode unit housed in a cell can and comprising a positive electrode and a negative electrode each formed by coating a surface of a striplike current collector with an electrode material. According to a first embodiment, the current collector of at least one of the positive electrode and the negative electrode comprises a plurality of current collector pieces 42 arranged along one direction and a PTC element 5 interconnecting each pair of adjacent current collector pieces 42. Alternatively with a second embodiment, at least one of the positive electrode and the negative electrode comprises a PTC element held between opposed faces of an uncoated portion of the current collector thereof and a base end portion of a current collector tab. The PTC element serves to prevent continuous occurrence of a current in excess of a predetermined value and realizes a high energy density.