Japan Storage Battery Co., Ltd.

Gs Yuasa Corporation

Atsushi Funabiki

Hideo Yasuda

Toshiyuki Nukuda

Taro Yamafuku

Yoshihiro Katayama

Shigeki Yamate

Suguru Kozono

Kazusa Yukimoto

A nonaqueous electrolytic cell manufacturing method is characterized in that a nonaqueous electrolyte containing vinylene carbonate is used, a coating on the surface of the negative electrode is formed at the initial charging/discharging in such a way by lowering the negative electrode potential to less than 0.4 V with relative to the lithium potential, wherein the nonaqueous electrolytic cell comprises a nonaqueous electrolyte containing an electrolytic salt and a nonaqueous solvent, a positive electrode, and a negative electrode containing a negative electrode material into/from which lithium ions are inserted/desorbed at a potential higher than the lithium potential by 1.2 V. The nonaqueous electrolytic cell is used in a range of negative electrode potential nobler than the lithium potential by 0.8 V.

Nonaqueous electrolytic cell and its manufacturing method

The positive active material for a secondary battery of the present invention is &#x3b2;-FeOOH containing at least one element selected from the group consisting of B, P, S, Li, Na, K, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Zr, Pb and Sn which shows a diffraction peak from the () plane having a half width Y satisfying 0.3&#xb0;&#x3c;Y (2&#x3b8;) when subjected to the X-ray diffractometry with the CuK&#x3b1; ray. A non-aqueous electrolyte secondary battery comprising as a positive active material such low-crystalline &#x3b2;-FeOOH exhibits an excellent cycle life performance as compared with a non-aqueous electrolyte secondary battery comprising a high-crystalline &#x3b2;-FeOOH as a positive active material.

Positive electrode active material for secondary cell, method for producing the same and nonaqueous electrolyte secondary cell comprising the same

The positive active material for secondary battery according to the invention comprises O, Fe in an amount of higher than 25% by weight, and V in an amount of from higher than 0% by weight to less than 35% by weight. The positive active material, when it is free of lithium, exhibits the following main peaks by the X-ray diffractometry using CuK&agr; rays: a peak within a 2&thgr; range of from greater than 26&deg; to less than 29&deg; and a peak within a 2&thgr; range of from greater than 29&deg; to less than 32&deg;. The non-aqueous secondary battery having a positive electrode comprising this positive active material exhibits a high capacity and good cycle life performance and is inexpensive and environmentally friendly.

Positive active material for secondary battery, process for preparation thereof and non-aqueous secondary battery comprising same

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Kyoto, Japan

Atsushi Funabiki