Mitsui Minings & Melting Co., Ltd.

Munetoshi Yamaguchi

Shinya Kagei

Yoshimi Hata

Koichi Numata

Yoshinobu Nakamura

Hirohisa Senzaki

A positive electrode active material for a lithium battery is provided which offers high-temperature storage property and battery properties and comprises manganese dioxide having a crystal structure that exhibits an X-ray diffraction pattern in which peaks having a peak intensity ratio of not less than 0.05 with respect to the peak at 2&#x3b8;=37.3&#xb0;&#xb1;0.5&#xb0; are present at positions of 2&#x3b8;=18.2&#xb0;&#xb1;0.5&#xb0;, 19.5&#xb0;&#xb1;0.5&#xb0;, 28.6&#xb0;&#xb1;0.5&#xb0;, 56.6&#xb0;&#xb1;0.5&#xb0;, 59.1&#xb0;&#xb1;0.5&#xb0;, and 65.1&#xb0;&#xb1;0.5&#xb0;, or further at 2&#x3b8;=22.0&#xb0;&#xb1;1.0&#xb0;, the X-ray diffraction pattern being obtained using a powder X-ray diffraction device (XRD) that uses CuK&#x3b1;1 rays.

Positive electrode active substance for lithium cell

A process for producing a lithium manganate for lithium secondary batteries comprising mixing a manganese compound and a lithium compound, firing the mixture at 1000 to 1500.degree. C., mixing the resulting complex oxide with a lithium compound, and firing the mixture at 600 to 800.degree. C.

Process for preparing lithium manganate for lithium secondary battery

A method of manufacturing manganese dioxide containing 0.05 to 2.0 parts by weight of phosphorus which consists of introducing a manganese sulfate solution and sulfuric acid as an electrolyte into an electrolytic cell, adding to said electrolyte at least one member selected from the group consisting of phosphoric acid, phosphorous acid, hypophosphorous acid and compounds thereof and carrying out the electrolysis at a bath temperature of 92.degree. to 100.degree. C. whereby manganese dioxide containing phosphorus is electrodeposited on the cathode.

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Takehara, Japan

Munetoshi Yamaguchi