Showa Denko K.k.

Showa Denko Kabushiki Kaisha

Takao Noda

Akihiko Shirakawa

Fumiyoshi Ono

Joseph Gaze

Yoshiaki Yamauchi

Kagetaka Ichikawa

A cathode electroactive material for use in lithium ion secondary cells, process for producing the material, and lithium ion secondary cells using the cathode electroactive material, wherein the electroactive material predominantly comprises an Li&#x2014;Mn composite oxide particles with the spinel structure and particles of the electroactive material have an average porosity of 15% or less, the porosity being calculated by employing the following equation:Porosity (%)=()&#xd7;100(wherein A represents a total cross-section area of pores included in a cross-section of one secondary particle, and B represents the cross-section area of one secondary particle), a tapping density of 1.9 g/ml or more, a size of crystallites of 400 &#x212b;&#x2013;960 &#x212b;, a lattice constant of 8.240 &#x212b; or less. The cathode electroactive material of the present invention is formed of particles which are dense and spherical and exhibit excellent packing characteristics to an electrode, and exhibit high initial capacity and capacity retention percentage at high temperature.

Cathode electroactive material, production method therefor and secondary cell

A cathode electroactive material for use in lithium ion secondary cells, process for producing the material, and lithium ion secondary cells using the cathode electroactive material, wherein the electroactive material predominantly comprises an Li&#x2014;Mn composite oxide particles with the spinel structure and particles of the electroactive material have an average porosity of 15% or less, the porosity being calculated by employing the following equation:Porosity (%)=()&#xd7;100(wherein A represents a total cross-section area of pores included in a cross-section of one secondary particle, and B represents the cross-section area of one secondary particle), a tapping density of 1.9 g/ml or more, a size of crystallites of 400 &#x212b;-960 &#x212b;, a lattice constant of 8.240 &#x212b; or less. The cathode electroactive material of the present invention is formed of particles which are dense and spherical and exhibit excellent packing characteristics to an electrode, and exhibit high initial capacity and capacity retention percentage at high temperature.

Cathode electroactive material, production method therefor, and nonaqueous secondary cell using the same

A cathode electroactive material is disclosed, comprising a compound oxide having a spinel structure. The compound oxide comprises lithium, manganese and oxygen and has an atomic ratio of lithium to manganese of Li/Mn&equals;0.48 to 0.55, a true density of 4.05 g/cm or more and a lattice constant of 8.240 &angst; or less. The compound oxide is obtained by mixing a lithium compound with manganese carbonate having a specific surface area of 10 m /g or more, then reacting the mixture at a temperature of from 350 to 680&deg; C. for at least one hour, and heat-treating the resulting spinel structure compound oxide at a temperature of from 730 to 900&deg; C. Also disclosed is a nonaqueous secondary battery comprising the cathode electroactive material.

Cathode electroactive material, production method and nonaqueous secondary battery comprising the same

A method for producing a high density boron nitride sintered body includes mixing high purity hexagonal boron nitride powder with 0.1 to 20% by weight of at least one alkaline earth metal, then shaping the resultant mixture and firing the resultant shaped body in a non-oxidizing atmosphere containing nitrogen.

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Chiba, Japan

Takao Noda