Tohoku University

Dowa Holdings Co., Ltd.

Sony Corporation

Norihiro Shimoi

Kazuyuki Tohji

Hiroyuki Kai

Yasumitsu Tanaka

Qiwu Zhang

Kenichi Kawase

Takakazu Hirose

Takashi Fujinaga

Isao Koizumi

A method for producing a negative electrode active material for a lithium ion secondary battery, comprising a step of charging either silicon and copper (II) oxide or silicon and copper metal in a pulverization device, pulverizing either the silicon and copper (II) oxide or silicon and copper metal, and simultaneously mixing either silicon and copper (II) oxide or silicon and copper metal thus pulverized. A negative electrode active material for a lithium ion secondary battery is produced by the method.

Method for producing negative electrode active material for lithium ion secondary battery

A negative electrode active material for a lithium ion secondary battery, comprising silicon, copper and oxygen as major constitutional elements, the negative electrode active material for a lithium ion secondary battery, containing fine particles of silicon having an average crystallite diameter (D) measured by an X-ray diffractometry of 50 nm or less, and having elemental ratios, expressed by molar ratios, Cu/(Si+Cu+O) and O/(Si+Cu+O) of from 0.02 to 0.30, wherein the negative electrode active material contains an intermetallic compound of silicon and copper.

Negative electrode active material for lithium ion secondary battery

In the case where a silicon substance having a high theoretical capacity as a negative electrode active material for a lithium ion secondary battery is used as a negative electrode active material, such a negative electrode active material is provided that has a high initial battery capacity and suffers less deterioration in performance even when many cycles of charge and discharge are repeated. A lithium ion secondary battery using the negative electrode active material is provided. Silicon and copper (II) oxide, or silicon, metallic copper and water are pulverized and simultaneously mixed in a pulverization device, thereby providing a negative electrode active material that has good cycle characteristics and a large battery capacity.

Negative electrode active material for lithium ion secondary battery, method for producing the same, negative electrode, and battery

A field electron emission film that is capable of being operated with low electric power and enhancing the uniformity in luminance within the light emission surface contains from 60 to 99.9% by mass of tin-doped indium oxide and from 0.1 to 20% by mass of carbon nanotubes. The film has a structure wherein grooves having a width in a range of from 0.1 to 50 mm are formed in a total extension of 2 mm or more per 1 mmon a surface of the film, and carbon nanotubes are exposed on a wall surface of the grooves. After forming an ITO film containing carbon nanotubes on a substrate, grooves are formed on a surface of the ITO film, and the end portions of the carbon nanotubes exposed to the wall surface of the grooves are designated as an emitter.

Field electron emission film, field electron emission device, light emission device, and method for producing them

A lithium ion secondary battery is provided with a positive electrode, a negative electrode containing an active material, and an electrolytic solution, wherein the active material includes a core portion capable of occluding and releasing lithium ions, an amorphous or low-crystalline coating portion disposed on at least a part of the surface of the core portion, and a fibrous carbon portion disposed on at least a part of the surface of the coating portion, and the coating portion contains Si and O as constituent elements, while the atomic ratio y (O/Si) of O relative to Si satisfies 0.5&#x2266;y&#x2266;1.8.

Lithium ion secondary battery, lithium ion secondary battery negative electrode, battery pack, electric vehicle, electricity storage system, power tool, and electronic apparatus

Growing community of inventors

Miyagi, Japan

Norihiro Shimoi