Japan Storage Battery Co., Ltd.

Other

Junichi Toriyama

Masanao Terasaki

Yoshinori Naruoka

Koji Hayashi

Hajime Kitamura

Koji Yamato

Atsuro Kondo

Takahiro Miyashita

A positive active material for non-aqueous electrolyte secondary battery is provided comprising lithium manganese oxide having such a spinel structure that the half-width (2&#x3b8;) of the reflection peak corresponding to 440 plane as determined by X-ray diffractometry using CuK&#x3b1; ray is not greater than 0.145&#xb0;. The use of this positive active material makes it possible to obtain a secondary battery which exhibits a good cycle life performance at room temperature and high temperatures and a reduced capacity drop when stored at high temperatures.

Positive active material for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery comprising same

A positive active material for a non-aqueous electrolyte secondary battery includes a lithium-nickel composite oxide represented by the compositional formula LiNiCOMnO(a&#x2266;1.09, 0.05&#x2266;b&#x2266;0.35, 0.15&#x2266;c&#x2266;0.35, and 0.25&#x2266;b+c&#x2266;0.55). By X-ray diffractometry with a CuK&#x3b1; ray, the lithium-nickel composite oxide exhibits an intensity ratio R ((I+I)/I) of not greater than 0.50, wherein R is the ratio of the sum of the diffraction peak intensity Ion the 012 plane and the diffraction peak intensity Ion the 006 plane to the diffraction peak intensity Ion the 101 plane. The crystallinity of the positive active material of the compositional formula LiNiCoMnOcan be kept high and it is possible to secure good capacity density and cycle life performance.

Nonaqueous electrolyte secondary cell and a tungsten or molybdenum substituted lithium positive electrode active material

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Kyoto, Japan

Junichi Toriyama