Abstract: A negative electrode material according to the present invention which is provided as an inexpensive negative electrode material for a nonaqueous electrolyte secondary battery and which suppresses the amount of expensive Co which is used contains three types of powder materials in the form of alloy material A, alloy material B, and a conductive material. Alloy material A comprises an alloy having a CoSn2 structure containing Co, Sn, and Fe and having an Sn content of at least 70.1 mass % and less than 82.0 mass %. Alloy material B comprises Co3Sn2 and has a lower discharge capacity than alloy material A, and the proportion RB of the mass of alloy material B based on the total mass of alloy material A and alloy material B is greater than 5.9% and less than 27.1%. The content of the conductive material is at least 7 mass % and at most 20 mass % based on the total mass of alloy material A, alloy material B, and the conductive material.

Abstract: Modified natural graphite particles intended for forming a negative electrode material for a nonaqueous electrolyte secondary battery are characterized by having a circularity of at least 0.93 and at most 1.0 and a surface roughness of at most 1.5% with respect to the length of the particles. These modified natural graphite particles are obtained by a manufacturing method including a step of applying an impact force to natural graphite particles for pulverization and spheroidization to obtain intermediate particles having a circularity of at least 0.93 and at most 1.0, and a step of carrying out surface smoothing of the resulting intermediate particles by mechanical grinding treatment to obtain the modified natural graphite particles.

Abstract: The present invention provides a negative electrode material for a nonaqueous electrolyte secondary battery which can improve the cycle properties of a lithium ion secondary battery and a method for manufacturing the negative electrode material. The negative electrode material comprises at least two types of powdery alloy materials A and B in which powdery alloy material A contains Co, Sn, and Fe and does not contain Ti and powdery alloy material B contains Fe, Ti, and Sn, and the proportion of the mass of powdery alloy material B to the sum of the mass of powdery alloy material A and the mass of powdery alloy material B is at least 10 mass % and at most 30 mass %.

Abstract: A graphite powder suitable for a negative electrode material of a lithium ion secondary battery which assures a high discharging capacity not lower than 320 mAh/g is to be manufactured at a lower cost. Specifically, a graphite powder containing 0.01 to 5.0 wt % of boron and having a looped closure structure at an end of a graphite c-planar layer on the surface of a powder, with the density of the interstitial planar sections between neighboring closure structures being not less than 100/?m and not more than 1500/?m, and with d002 being preferably not larger than 3.3650 ?, is manufactured by (1) heat-treating a carbon material pulverized at an elevated speed before or after carbonization for graphization at temperature exceeding 1500° C. or by (2) heat-treating the carbon material pulverized before or after carbonization at a temperature exceeding 1500° C.

Abstract: A graphite powder suitable for a negative electrode material of a lithium ion secondary battery which assures a high discharging capacity not lower than 320 mAh/g is to be manufactured at a lower cost. Specifically, a graphite powder containing 0.01 to 5.0 wt % of boron and having a looped closure structure at an end of a graphite c-planar layer on the surface of a powder, with the density of the interstitial planar sections between neighboring closure structures being not less than 100/?m and not more than 1500/?m, and with d002 being preferably not larger than 3.3650 ?, is manufactured by (1) heat-treating a carbon material pulverized at an elevated speed before or after carbonization for graphization at temperature exceeding 1500° C. or by (2) heat-treating the carbon material pulverized before or after carbonization at a temperature exceeding 1500° C.

Abstract: A graphite powder suitable for a negative electrode material of a lithium ion secondary battery which assures a high discharging capacity not lower than 320 mAh/g is to be manufactured at a lower cost. Specifically, a graphite powder containing 0.01 to 5.0 wt % of boron and having a looped closure structure at an end of a graphite c-planar layer on the surface of a powder, with the density of the interstitial planar sections between neighboring closure structures being not less than 100/?m and not more than 1500/?m, and with d002 being preferably not larger than 3.3650 ?, is manufactured by (1) heat-treating a carbon material pulverized at an elevated speed before or after carbonization for graphization at temperature exceeding 1500° C. or by (2) heat-treating the carbon material pulverized before or after carbonization at a temperature exceeding 1500° C.

Abstract: A graphite powder suitable for a negative electrode material of a lithium ion secondary battery which assures a high discharging capacity not lower than 320 mAh/g is to be manufactured at a lower cost. Specifically, a graphite powder containing 0.01 to 5.0 wt % of boron and having a looped closure structure at an end of a graphite c-planar layer on the surface of a powder, with the density of the interstitial planar sections between neighboring closure structures being not less than 100/?m and not more than 1500/?m, and with d002 being preferably not larger than 3.3650 ?, is manufactured by (1) heat-treating a carbon material pulverized at an elevated speed before or after carbonization for graphization at temperature exceeding 1500° C. or by (2) heat-treating the carbon material pulverized before or after carbonization at a temperature exceeding 1500° C.

Abstract: A negative electrode material for a nonaqueous electrolyte secondary battery having a high discharge capacity and a good cycle life is made from alloy particles having an average particle diameter of 0.1-50 ?m and including Si phase grains 40 and a phase of a solid solution or an intermetallic compound of Si and other element selected from Group 2A elements, transition elements, Group 3B elements, and Group 4B elements from the long form periodic table (for example, an NiSi2 phase 42 and an [NiSi2+NiSi] phase 41) at least partially enveloping the Si phase grains. 5-99 wt % of this material is Si phase grains. The alloy particles can be manufactured by rapid solidification (such as atomization or roller quenching) of a melt including Si and the other element, or by adhering the other element to Si powder by electroless plating or mechanical alloying and then performing heat treatment.

Abstract: A negative electrode material for a nonaqueous electrolyte secondary battery having a high discharge capacity and a good cycle life is made from alloy particles having an average particle diameter of 0.1-50 &mgr;m and including Si phase grains 40 and a phase of a solid solution or an intermetallic compound of Si and other element selected from Group 2A elements, transition elements, Group 3B elements, and Group 4B elements from the long form periodic table (for example, an NiSi2 phase 42 and an [NiSi2+NiSi] phase 41) at least partially enveloping the Si phase grains. 5-99 wt % of this material is Si phase grains. The alloy particles can be manufactured by rapid solidification (such as atomization or roller quenching) of a melt including Si and the other element, or by adhering the other element to Si powder by electroless plating or mechanical alloying and then performing heat treatment.

Abstract: A graphite powder suitable for a negative electrode material of a lithium ion secondary battery which assures a high discharging capacity not lower than 320 mAh/g is to be manufactured at a lower cost. Specifically, a graphite powder containing 0.01 to 5.0 wt % of boron and having a looped closure structure at an end of a graphite c-planar layer on the surface of a powder, with the density of the interstitial planar sections between neighboring closure structures being not less than 100/&mgr;m and not more than 1500/&mgr;m, and with d002 being preferably not larger than 3.3650 Å, is manufactured by (1) heat-treating a carbon material pulverized at an elevated speed before or after carbonization for graphization at temperature exceeding 1500° C. or by (2) heat-treating the carbon material pulverized before or after carbonization at a temperature exceeding 1500° C.

Abstract: A negative electrode material for a nonaqueous electrolyte secondary battery having a high discharge capacity and a good cycle life is made from alloy particles having an average particle diameter of 0.1-50 &mgr;m and including Si phase grains 40 and a phase of a solid solution or an intermetallic compound of Si and other element selected from Group 2A elements, transition elements, Group 3B elements, and Group 4B elements from the long form periodic table (for example, an NiSi2 phase 42 and an [NiSi2+NiSi] phase 41) at least partially enveloping the Si phase grains. 5-99 wt % of this material is Si phase grains. The alloy particles can be manufactured by rapid solidification (such as atomization or roller quenching) of a melt including Si and the other element, or by adhering the other element to Si powder by electroless plating or mechanical alloying and then performing heat treatment.

Abstract: A graphite powder has surface closed-end structures in which the graphite c-plane layers of the graphite layer crystal lattices have closed-ends on the surface of the graphite powder by linking the ends of one or more pairs of the c-plane layers, leaving interstices which are open on the surface of the graphite. The number of open interstices is at least 100 and at most 1500 per micrometer in a c-axis direction of the graphite. Preferably, the graphite powder has a specific surface area of 1.0 m2/g or less. Such a graphite powder can be prepared either by graphitizing a carbon material, which has been pulverized at a high speed under well-controlled conditions before and/or after the carbonization, or by subjecting a carbon material, which has been pulverized under well-controlled conditions before and/or after the carbonization, to graphitization and then to oxidative heat treatment at a temperature of 600-800° C. and finally to heat treatment at a temperature of 800° C. or higher in an inert gas.

Abstract: A graphite powder suitable for a negative electrode material of a lithium ion secondary battery which assures a high discharging capacity not lower than 320 mAh/g is to be manufactured at a lower cost. Specifically, a graphite powder containing 0.01 to 5.0 wt % of boron and having a looped closure structure at an end of a graphite c-planar layer on the surface of a powder, with the density of the interstitial planar sections between neighboring closure structures being not less than 100/&mgr;m and not more than 1500/&mgr;m, and with d002 being preferably not larger than 3.3650 Å, is manufactured by (1) heat-treating a carbon material pulverized at an elevated speed before or after carbonization for graphization at temperature exceeding 1500° C. or by (2) heat-treating the carbon material pulverized before or after carbonization at a temperature exceeding 1500° C.