Patents by Inventor Tetsuya Yamawaki

Tetsuya Yamawaki has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method for preparing lithium manganate and positive electrode for lithium secondary cell containing the same
    Patent number: 6699297
    Abstract: A method for preparing lithium manganate having spinel structure which comprises contacting a manganese halide and lithium compound at a temperature of 100° C. or less in a liquid phase to react with each other; a lithium manganate which is prepared according to the method, is represented by the formula LixMnOy, wherein x represents a real number satisfying 0<x≦0.8, and y represents a real number satisfying 1.8≦y≦2.4, and has an average particle diameter of 1 to 50 &mgr;m and a specific surface area of 10 to 15 m2/g; a positive electrode for a lithium secondary cell comprising the lithium manganate as an active material; and a lithium secondary cell using the positive electrode.
    Type: Grant
    Filed: September 17, 2001
    Date of Patent: March 2, 2004
    Assignee: Toho Titanium Co., Ltd.
    Inventors: Tetsuya Yamawaki, Hideki Sakai
  • Process for producing lithium titanate and lithium ion battery and negative electrode therein
    Patent number: 6645673
    Abstract: In a process for producing lithium titanate, a mixture of titanium dioxide and at least one lithium compound selected from the group consisting of lithium carbonate, lithium hydroxide, lithium nitrate, and lithium oxide is presintered at a temperature of between 670° C. or more and less than 800° C. to prepare a compound consisting of TiO2 and Li2TiO3 or a compound consisting of TiO2, Li2TiO3 and Li4Ti5O12. The compound is then sintered at a temperature in the range of 800 to 950° C.
    Type: Grant
    Filed: January 25, 2001
    Date of Patent: November 11, 2003
    Assignee: Toho Titanium Co., Ltd.
    Inventors: Tetsuya Yamawaki, Kiyoshi Eto, Hideki Sakai
  • Process for producing lithium titanate and lithium ion battery and negative electrode therein
    Patent number: 6475673
    Abstract: In a process for producing lithium titanate, a mixture of titanium dioxide and at least one lithium compound selected from the group consisting of lithium carbonate, lithium hydroxide, lithium nitrate, and lithium oxide is presintered at a temperature of 670° C. or more and less than 800° C. to yield a composition consisting of TiO2 and Li2TiO3 or a composition consisting of TiO2, Li2TiO3 and Li4Ti5O12. The composition is then sintered at a temperature in the range of 800 to 950° C.
    Type: Grant
    Filed: February 10, 2000
    Date of Patent: November 5, 2002
    Assignee: Toho Titanium Co., Ltd.
    Inventors: Tetsuya Yamawaki, Kiyoshi Eto, Hideki Sakai
  • Process for producing lithium titanate and lithium ion battery and negative electrode therein
    Publication number: 20010031401
    Abstract: In a process for producing lithium titanate, a mixture of titanium dioxide and at least one lithium compound selected from the group consisting of lithium carbonate, lithium hydroxide, lithium nitrate, and lithium oxide is presintered at a temperature of between 670° C. or more and less than 800° C. to prepare a compound consisting of TiO2 and Li2TiO3 or a compound consisting of TiO2, Li2TiO3 and Li4Ti5O12. The compound is then sintered at a temperature in the range of 800 to 950° C.
    Type: Application
    Filed: January 25, 2001
    Publication date: October 18, 2001
    Inventors: Tetsuya Yamawaki, Kiyoshi Eto, Hideki Sakai