Abstract: A lithium secondary battery of the present invention includes: a positive electrode; a negative electrode; a nonaqueous electrolytic solution; and a separator. The positive active material contains a lithium-containing composite oxide containing nickel. A molar ratio of a total nickel amount with respect to a total lithium amount contained in the entire positive active material is 0.05 to 1.0. The nonaqueous electrolytic solution contains 0.5 to 5.0 mass % of a phosphonoacetate-based compound represented by the following General Formula (1). In the Formula, R1, R2, and R3 independently represent an alkyl group, an alkenyl group, or an alkynyl group having 1 to 12 carbon atoms, which may be substituted by a halogen atom, and “n” represents an integer of 0 to 6.

Abstract: A lithium secondary battery positive electrode according to the present invention is a lithium secondary battery positive electrode including a positive electrode material mixture layer containing a positive electrode active material and a conductivity enhancing agent on one or both sides of a current collector, wherein the positive electrode active material contains a lithium-containing composite oxide, the conductivity enhancing agent contains carbon fibers having an average fiber length of 10 nm or more and less than 1000 nm and an average fiber diameter of 1 nm or more and 100 nm or less, and the content of the carbon fibers in the positive electrode material mixture layer is 0.25 mass % or more and 1.5 mass % or less.

Abstract: There is provided a lithium secondary battery including a positive electrode, a negative electrode, a nonaqueous electrolyte liquid and a separator, that is subjected to a constant-current constant-voltage charge with a stop voltage of more than 4.25V before its use. The lithium secondary battery uses the nonaqueous electrolyte liquid having contained 0.1 to 5 mass % of a phosphonoacetate compound represented by the following general formula (1), and having contained 0.1 to 5 mass % of 1,3-dioxane. In General Formula (1), each of R1, R2 and R3 is independently hydrocarbon groups having a carbon number of 1 to 12 with or without substituent of a halogen atom, and n is 0 to 6 integers.

Abstract: A lithium secondary battery of the present invention includes: a positive electrode; a negative electrode; a nonaqueous electrolytic solution; and a separator. The positive active material contains a lithium-containing composite oxide containing nickel. A molar ratio of a total nickel amount with respect to a total lithium amount contained in the entire positive active material is 0.05 to 1.0. The nonaqueous electrolytic solution contains 0.5 to 5.0 mass % of a phosphonoacetate-based compound represented by the following General Formula (1). In the Formula, R1, R2, and R3 independently represent an alkyl group, an alkenyl group, or an alkynyl group having 1 to 12 carbon atoms, which may be substituted by a halogen atom, and “n” represents an integer of 0 to 6.

Abstract: A lithium secondary-battery pack of the present invention includes: a lithium secondary battery including an electrode body and a non-aqueous electrolyte, the electrode body including a positive electrode and a negative electrode facing each other, and a separator interposed therebetween; a PTC (Positive Temperature Coefficient) element; and a protection circuit including a field-effect transistor, wherein the negative electrode includes a negative electrode material mixture layer containing a Si-containing material as a negative electrode active material, and, where Z represents an impedance (?) of the lithium secondary-battery pack and Q represents a capacity (Ah) of the lithium secondary-battery pack, an impedance capacity index represented by Z/Q is 0.055 ?/Ah or less.

Abstract: There is provided a lithium secondary battery including a positive electrode, a negative electrode, a nonaqueous electrolyte liquid and a separator, that is subjected to a constant-current constant-voltage charge with a stop voltage of more than 4.25V before its use. The lithium secondary battery uses the nonaqueous electrolyte liquid having contained 0.1 to 5 mass % of a phosphonoacetate compound represented by the following general formula (1), and having contained 0.1 to 5 mass % of 1,3-dioxane. In General Formula (1), each of R1, R2 and R3 is independently hydrocarbon groups having a carbon number of 1 to 12 with or without substituent of a halogen atom, and n is 0 to 6 integers.

Abstract: A lithium secondary battery positive electrode according to the present invention is a lithium secondary battery positive electrode including a positive electrode material mixture layer containing a positive electrode active material and a conductivity enhancing agent on one or both sides of a current collector, wherein the positive electrode active material contains a lithium-containing composite oxide, the conductivity enhancing agent contains carbon fibers having an average fiber length of 10 nm or more and less than 1000 nm and an average fiber diameter of 1 nm or more and 100 nm or less, and the content of the carbon fibers in the positive electrode material mixture layer is 0.25 mass % or more and 1.5 mass % or less.

Abstract: A lithium secondary battery positive electrode of the present invention includes a positive electrode material mixture layer containing a positive electrode active material, a conductivity enhancing agent and a binder on one or both sides of a current collector, and the positive electrode active material contains a lithium-containing composite oxide represented by the general compositional formula: Li1+xMO2, where x is in a range of ?0.15?x?0.15 and M represents an element group of three or more elements including at least Ni, Co and Mn. The binder contains a tetrafluoroethylene-vinylidene fluoride copolymer (P(TFE-VDF)) and polyvinylidene fluoride (PVDF). The total content of the binder in the positive electrode material mixture layer is 1 to 4 mass %, and the ratio of the P(TFE-VDF) is 10 mass % or more, when the total of the P(TFE-VDF) and the PVDF is taken as 100 mass %.

Abstract: A porous element containing a fluoropolymer comprising vinylidene fluoride as a main unit and having a density of 0.55–1.30 g/cm3 and a Gurley value of not more than 150 sec/100 cc is used as a polymer substrate of a solid electrolyte to be placed between a positive electrode and a negative electrode. As a result, the solid electrolyte layer shows fine ion conductivity and an ion polymer secondary battery having strikingly improved low temperature characteristics, cycle characteristics and high-rate discharge characteristics as compared to conventional batteries can be obtained.

Abstract: A porous element containing a fluoropolymer comprising vinylidene fluoride as a main unit and having a density of 0.55-1.30 g/cm3 and a Gurley value of not more than 150 sec/100 cc is used as a polymer substrate of a solid electrolyte to be placed between a positive electrode and a negative electrode. As a result, the solid electrolyte layer shows fine ion conductivity and an ion polymer secondary battery having strikingly improved low temperature characteristics, cycle characteristics and high-rate discharge characteristics as compared to conventional batteries can be obtained.

Abstract: Using a crystal (lithium cobaltate) having a crystallite size in the direction of (003) plane of not less than 800 angstrom and a coordination number of a cobalt atom to a different cobalt atom of not less than 5.7 as a positive electrode active material, a lithium ion secondary battery is formed. As a result, the rate characteristic, low temperature characteristic, cycle characteristic and the like of the lithium ion secondary battery can be improved. In addition, by combining a preferable embodiment of the positive plate such as (an embodiment wherein not more than 50% of the surface of a positive electrode active material is covered with a conductive material), (an embodiment wherein two kinds of conductive materials having a particle size of not less than 3 &mgr;m and a particle size of not more than 2 &mgr;m are used, or one kind of a conductive material having a particle size of not more than 10 &mgr;m is used and the porosity of the positive electrode coating layer is 0.08 cc/g-0.

Abstract: The present invention relates to a positive electrode active material, a negative electrode active material and an electrolyte that are used alone or in combination to improve charge and discharge cycle characteristic, low temperature characteristic and safety of a non-aqueous electrolyic secondary battery, particularly a lithium ion secondary battery. Specifically, a particulate Li-transition metal composite oxide having an average particle size of not less than 10 &mgr;m, wherein [20/(specific surface area×average particle size)]=7-9, is used as a positive electrode active material.