Ricoh Company, Ltd.

Unitika Ltd.

Katsuo Inoue

Toshiyuki Kabata

Yoshiaki Echigo

Toshiyuki Ohsawa

Keiichi Asami

Hideki Takahashi

Okitoshi Kimura

The present invention provides a composite sheet electrode which has high strength, excellent current collecting properties and which is used efficiently as an active material for an electrode. The electrode has excellent discharge capacities and can be easily formed into an electrode terminal. A cell employing this electrode is also disclosed. The invention also provides a composite sheet electrode having a porosity of 20 to 80% containing 5 to 95% by weight of an active material of an electrode, 1 to 50% by weight of a current collecting material and heat fusible short fibers. The present invention also provides a composite sheet electrode having a porosity of 20 to 80%, which is made up of a composite sheet containing 5 to 95% by weight of an active material as an electrode and 5 to 95% by weight of heat fusible short fibers, as well as a current collecting material layer formed on said composite sheet. The present invention further provides a cell employing the latter-mentioned composite sheet electrode.

Composite sheet electrode

The present invention provides a carbonaceous material suitable for an electrode of a secondary cell. The carbonaceous material has a specific surface area by BET method of at least 10 m.sup.2 /g and a nitrogen/carbon atom weight ratio of 0.15 to 0.01, and is obtained by heat-treating a polyimide polymer having repeating units represented by: ##STR1## wherein R represents a 4 valent aromatic residue having at least one aromatic ring, of which each 2 valences are bonded with an adjacent carbon atom in the aromatic ring, R' represents a divalent aromatic residue having 1 to 4 aromatic rings and n is an integer of at least 2. The present invention also provides a secondary cell using the above mentioned carbonaceous material as electrode.

Carbonaceous material and a cell using the same

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Uji, Japan

Katsuo Inoue