Abstract: The main object is to provide a novel material with excellent charge and discharge characteristics, such as a high utilization rate of a positive electrode, a high capacity, and good cycle characteristic, in which the material is a compound containing as the major component lithium sulfide useful as a cathode active material for lithium secondary batteries. The invention provides a lithium sulfide-iron-carbon composite containing lithium, iron, sulfur and carbon as constituent elements, with lithium sulfide (Li2S), as the main phase, having a crystallite size of 50 nm or less as calculated from the half width of the diffraction peak based on the (111) plane of Li2S as determined by X-ray powder diffraction.

Abstract: The sulfide of the present invention comprises an amorphous (lithium) niobium sulfide having an average composition represented by formula (1): Lik1NbSn1 (wherein 0?k1?5; 3?n1?10; and when n1?3.5, k1?0.5), or an amorphous (lithium) titanium niobium sulfide having an average composition represented by formula (2): Lik2Ti1-m2Nbm2Sn2 (wherein 0?k2?5; 0<m2<1; 2?n2?10; and when n2?3.5, k2?1.5). The sulfide of the present invention is a material that is useful as a cathode active material for lithium batteries, such as lithium primary batteries, lithium secondary batteries, and lithium ion secondary batteries, and has a high charge-discharge capacity, high electrical conductivity, and excellent charge-discharge performance.

Abstract: The present invention provides a novel lithium titanium sulfide, lithium niobium sulfide, or lithium titanium niobium sulfide that contains a sulfide containing lithium, titanium and/or niobium, and sulfur as constituent elements, and that has excellent charge-discharge performance (especially excellent charge-discharge capacity and charge-discharge potential) useful as a cathode active material or the like for lithium batteries, such as metal lithium secondary batteries or lithium-ion secondary batteries.

Abstract: The sulfide of the present invention comprises an amorphous (lithium) niobium sulfide having an average composition represented by formula (1): Lik1NbSn1 (wherein 0?k1?5; 3?n1?10; and when n1?3.5, k1?0.5), or an amorphous (lithium) titanium niobium sulfide having an average composition represented by formula (2): Lik2Ti1-m2Nbm2Sn2 (wherein 0?k2?5; 0<m2<1; 2?n2?10; and when n2?3.5, k2?1.5). The sulfide of the present invention is a material that is useful as a cathode active material for lithium batteries, such as lithium primary batteries, lithium secondary batteries, and lithium ion secondary batteries, and has a high charge-discharge capacity, high electrical conductivity, and excellent charge-discharge performance.

Abstract: The present invention provides a novel lithium titanium sulfide, lithium niobium sulfide, or lithium titanium niobium sulfide that contains a sulfide containing lithium, titanium and/or niobium, and sulfur as constituent elements, and that has excellent charge-discharge performance (especially excellent charge-discharge capacity and charge-discharge potential) useful as a cathode active material or the like for lithium batteries, such as metal lithium secondary batteries or lithium-ion secondary batteries.

Abstract: The main object is to provide a novel material with excellent charge and discharge characteristics, such as a high utilization rate of a positive electrode, a high capacity, and good cycle characteristic, in which the material is a compound containing as the major component lithium sulfide useful as a cathode active material for lithium secondary batteries. The invention provides a lithium sulfide-iron-carbon composite containing lithium, iron, sulfur and carbon as constituent elements, with lithium sulfide (Li2S), as the main phase, having a crystallite size of 50 nm or less as calculated from the half width of the diffraction peak based on the (111) plane of Li2S as determined by X-ray powder diffraction.

Abstract: The present invention provides a process for producing a lithium sulfide-carbon composite, the process comprising placing a mixture of lithium sulfide and a carbon material having a specific surface area of 60 m2/g or more in an electrically-conductive mold in a non-oxidizing atmosphere, and applying a pulsed direct current to the mold while pressurizing the mixture in a non-oxidizing atmosphere, thereby subjecting the lithium sulfide and the carbon material to heating reaction; and a lithium sulfide-carbon composite obtained by this process, the composite having a carbon content of 15 to 70 weight %, and a tap density of 0.4 g/cm3 or more when the carbon content is 30 weight % or more, or a tap density of 0.5 g/cm3 or more when the carbon content is less than 30 weight %.

Abstract: The present invention provides a process for producing a composite of metal sulfide and metal oxide obtained by dispersing a metal sulfide, which is nickel sulfide, copper sulfide, iron sulfide or a mixture thereof, in a metal salt-containing aqueous solution, and depositing metal salt on the metal sulfide by drying the aqueous solution; and heat-treating the metal sulfide comprising a metal salt deposited thereon at 400 to 900° C. in a sulfur-containing atmosphere. Also disclosed is a composite obtained by the aforementioned process, comprising a metal sulfide having a surface partially covered with a metal oxide. The composite of the present invention has improved cycle characteristics while maintaining a high charge/discharge capacity and excellent electrical conductivity inherently possessed by metal sulfide, which is usable as a material having a high theoretical capacity and excellent electrical conductivity when used as a positive-electrode material for a lithium secondary battery.

Abstract: The present invention provides a production process of a metal sulfide, which includes placing a metal component and sulfur in a conductive container, and applying a pulsed direct current to the container in a non-oxidizing atmosphere to cause the metal component to react with sulfur, and also provides a metal sulfide obtained by the process and represented by a composition formula: MSx, wherein M is at least one member selected from the group consisting of Ni, Cu, Fe, and Co, and 1<x?2. The present invention is capable of easily producing a metal sulfide with a high proportion of sulfur atoms, which is expected to exhibit excellent properties as a positive-electrode active material for a high capacity lithium secondary battery.

Abstract: The present invention provides a lithium manganese-based composite oxide represented by the compositional formula: Li1+x(Mn1-m-nFemTin)1?xO2, wherein 0<x<?, 0?m?0.75, 0.01?n?0.75, and 0.01?m+n<1, and comprising a crystal phase of layered rock-salt type structure. The composite oxide is capable of maintaining an average discharge voltage of 3 V or more over long charge/discharge cycles. The composite oxide can be prepared using lower-cost starting materials, and exhibits improved charge/discharge characteristics over conventional low-cost positive electrode materials.

Abstract: The present invention provides a production process of a metal sulfide, which includes placing a metal component and sulfur in a conductive container, and applying a pulsed direct current to the container in a non-oxidizing atmosphere to cause the metal component to react with sulfur, and also provides a metal sulfide obtained by the process and represented by a composition formula: MSx, wherein M is at least one member selected from the group consisting of Ni, Cu, Fe, and Co, and 1<x?2. The present invention is capable of easily producing a metal sulfide with a high proportion of sulfur atoms, which is expected to exhibit excellent properties as a positive-electrode active material for a high capacity lithium secondary battery.

Abstract: The present invention provides a process for producing a lithium sulfide-carbon composite, the process comprising placing a mixture of lithium sulfide and a carbon material having a specific surface area of 60 m2/g or more in an electrically-conductive mold in a non-oxidizing atmosphere, and applying a pulsed direct current to the mold while pressurizing the mixture in a non-oxidizing atmosphere, thereby subjecting the lithium sulfide and the carbon material to heating reaction; and a lithium sulfide-carbon composite obtained by this process, the composite having a carbon content of 15 to 70 weight %, and a tap density of 0.4 g/cm3 or more when the carbon content is 30 weight % or more, or a tap density of 0.5 g/cm3 or more when the carbon content is less than 30 weight %.

Abstract: The present invention provides a process for producing a composite of metal sulfide and metal oxide obtained by dispersing a metal sulfide, which is nickel sulfide, copper sulfide, iron sulfide or a mixture thereof, in a metal salt-containing aqueous solution, and depositing metal salt on the metal sulfide by drying the aqueous solution; and heat-treating the metal sulfide comprising a metal salt deposited thereon at 400 to 900° C. in a sulfur-containing atmosphere. Also disclosed is a composite obtained by the aforementioned process, comprising a metal sulfide having a surface partially covered with a metal oxide. The composite of the present invention has improved cycle characteristics while maintaining a high charge/discharge capacity and excellent electrical conductivity inherently possessed by metal sulfide, which is usable as a material having a high theoretical capacity and excellent electrical conductivity when used as a positive-electrode material for a lithium secondary battery.

Abstract: The invention provides a lithium-manganese-based composite oxide containing Ti and Ni, which is represented by the compositional formula: Li1+x(Mn1?n?mNimTin)1?xO2, wherein 0<x?0.33, 0.05<m<0.3, and 0.3<n<0.5, and includes a crystal phase of layered rock-salt type structure. The composite oxide is a novel material that is capable of maintaining an average discharge voltage of 3 V or more over long charge/discharge cycles, while providing a discharge capacity equal to or higher than those of lithium-cobalt-oxide-based positive electrode materials, and that can be prepared using starting materials that are inexpensive and less limited as natural resources, while exhibiting improved charge/discharge characteristics over known low-cost positive electrode materials.

Abstract: The invention provides a lithium-manganese-based composite oxide containing Ti and Ni, which is represented by the compositional formula: Li1+x(Mn1-n-mNimTin)1-xO2, wherein 0<x?0.33, 0.05<m<0.3, and 0.3<n<0.5, and includes a crystal phase of layered rock-salt type structure. The composite oxide is a novel material that is capable of maintaining an average discharge voltage of 3 V or more over long charge/discharge cycles, while providing a discharge capacity equal to or higher than those of lithium-cobalt-oxide-based positive electrode materials, and that can be prepared using starting materials that are inexpensive and less limited as natural resources, while exhibiting improved charge/discharge characteristics over known low-cost positive electrode materials.

Abstract: The present invention provides a lithium manganese-based composite oxide represented by the compositional formula: Li1+x(Mnl-m-nFemTin)1-xO2, wherein 0<x<?, 0?m?0.75, 0.01?n?0.75, and 0.01?m+n<1, and comprising a crystal phase of layered rock-salt type structure. The composite oxide is capable of maintaining an average discharge voltage of 3 V or more over long charge/discharge cycles. The composite oxide can be prepared using lower-cost starting materials, and exhibits improved charge/discharge characteristics over conventional low-cost positive electrode materials.

Abstract: A C/C composite including a carbon matrix and carbon fibers and exhibiting a crystal structure of the carbon matrix differing between (a) the portion at and in the vicinity of the interface between the carbon fibers and the carbon matrix and (b) the other portion of the carbon matrix and excelling in strength and thermal conductivity is produced by a method which includes intercalating a carbonizing catalyst in carbon fibers, causing said carbon fibers having said carbonizing catalyst intercalated therein to be impregnated with a precursor of a carbon matrix, and then firing the product of impregnation.

Abstract: A C/C composite including a carbon matrix and carbon fibers and exhibiting a crystal structure of the carbon matrix differing between (a) the portion at and in the vicinity of the interface between the carbon fibers and the carbon matrix and (b) the other portion of the carbon matrix and excelling in strength and thermal conductivity is produced by a method which includes intercalating a carbonizing catalyst in carbon fibers, causing said carbon fibers having said carbonizing catalyst intercalated therein to be impregnated with a precursor of a carbon matrix, and then firing the product of impregnation.