Kabushiki Kaisha Toshiba

Shouta Endou

Yasuhiro Shirakawa

Hajime Takeuchi

Yasumasa Ooya

Koshin Tanaka

Kazuki Amemiya

A positive electrode active material for use in a non-aqueous electrolyte secondary cell comprises a powdery metal oxide (LiCoO, LiNiO, LiMnOor the like). When the positive electrode active material is classified with a classification precision index &#x3ba; of 0.7 or greater so as to obtain a coarse powder having a classification ratio in a range of 0.1% to 5%, a ratio (B/A) of the content (B) of an impurity metal element in the coarse powder obtained by the classification to the content (A) of the impurity metal element in the powder before the classification is 1.5 or less. The contents of the impurity metal elements are compared with respect to Ca, Mn, Fe, Cr, Cu, Zn and the like (exclusive of the metal element constituting the powdery metal oxide). The positive electrode active material for a secondary cell serves to improve cell performance capabilities and production yields.

Positive electrode active material for secondary cell and nonaqueous electrolyte secondary cell using the same, and method for analysis of positive electrode active material for secondary cell

The present invention provides a positive electrode active material comprising: a positive electrode active material body; and at least one of oxide particles and carbon particles each having an average diameter of 1 &mgr;m or less; wherein at least one of oxide particles and carbon particles are adhered to a surface of the positive electrode active material body. I is preferable that a mass of the oxide particles adhered to the positive electrode material body is 0.001-2% of a mass of the positive electrode active material body. According to the above structure, there can be provided a positive electrode active material and non-aqueous secondary battery using the same capable of increasing a molding density (packing density) of the active material in a positive electrode, and capable of improving discharging rate characteristic of the battery by lowering an impedance of the electrode.

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Yokohama, Japan

Shouta Endou