Ishihara Sangyo Kaisha, Ltd.

Masatoshi Honma

Yusuke Okuda

Kazuyoshi Takeshima

Nariaki Moriyama

Tsunehisa Takeuchi

Tokuo Suita

Tomoyuki Sotokawa

Hirofumi Taniguchi

Naoya Nagahashi

Masanori Tomonari

Masaki Yoshio

Toshihiko Kawamura

Yoshiyuki Kunifusa

Atsushi Ishizawa

The invention provides a low-cost, efficient method for producing lithium titanate that is useful for applications in electric storage devices. The desired lithium titanate can be obtained by heating at least (1) titanium oxide having a BET single point specific surface area of 50 to 450 m/g based on nitrogen adsorption and (2) a lithium compound. Preferably the titanium oxide and lithium compound are heated together with (3) a lithium titanate compound having the same crystal structure as the desired lithium titanate. Preferably these ingredients are dry-mixed before heating.

Titanium raw material for lithium titanate production and method for producing lithium titanate using same

Disclosed is lithium titanate having excellent rate properties and useful for electricity storage devices, which is produced by preparing lithium titanate secondary particles that are aggregates of lithium titanate primary particles and forming at least macro-pores on the surfaces of the secondary particles. The lithium titanate can be produced by a process which comprises drying and granulating a slurry comprising crystalline titan oxide, a titanic acid compound and a lithium compound and firing the granulated product to thereby produce lithium titanate secondary particles, wherein (1) the crystalline titan oxide to be used comprises at least two types of crystalline titan oxide particles having different average particle diameters from each other, and/or (2) the crystalline titan oxide is used in an amount at least four-fold larger than that of the titanic acid compound in terms of TiOcontent by weight. The lithium titanate can achieve a satisfactory level of charge-discharge capacity for practical uses when used in a electricity storage device without requiring the use of a carbon-containing substance, such as carbon black, acethylene black or Ketjen black, as an electrically conductive material in combination, in spite of a fact that lithium titanate has an electrically insulating properties by nature.

Lithium titanate, electrode active material and electricity storage device each comprising the same

Provided is a process for manufacturing, at a low cost and efficiently, lithium titanium oxides which are useful for electricity storage devices. A desired lithium titanium oxide can be obtained by heating at least both (1) a titanium compound and (2) a lithium compound that has a volume-mean particle diameter of 5 &#x3bc;m or less. The lithium compound is preferably obtained by adjusting the volume-mean particle diameter to 5 &#x3bc;m or less by pulverizing. It is preferable that the titanium compound and the lithium compound are heated together with (3) a lithium titanium oxide compound that has the same crystal structure as that of objective lithium titanium oxide. It is preferable that these materials are dry-blended prior to the heating.

Process for manufacturing lithium titanium oxides

A method for producing a lithium titanate precursor includes the step of grinding a lithium compound and a titanium compound in a state where these compounds coexist. More preferably, a method for producing a lithium titanate precursor includes the steps of; mixing a lithium compound and a titanium compound; and grinding the lithium compound and the titanium compound in a state where these compounds coexist by the mixing.

Method for producing lithium titanate precursor, method for producing lithium titanate, lithium titanate, electrode active material, and electricity storage device

This invention provides a titanic acid compound-type electrode active material having a high battery capacity and, at the same time, having excellent cycle characteristics. The titanic acid compound exhibits an X-ray diffraction pattern corresponding to a bronze-type titanium dioxide except for a peak for a (003) face and a (&#x2212;601) face and having a lattice spacing difference between the (003) face and the (&#x2212;601) face, i.e., d&#x2212;d, of not more than 0.0040 nm. The titanic acid compound may be produced by reacting a layered alkali metal titanate, represented by a compositional formula MM'TiOwherein M and M&#x2032;, which may be the same or different, represent an alkali metal; and x is in the range of 0.50 to 1.0, with an acidic compound and then heating the reaction product at a temperature in the range of 250 to 450&#xb0; C.

Titanic acid compound, process for producing the titanic acid compound, electrode active material containing the titanic acid compound, and storage device using the electrode active material

Disclosed is a storage device comprising a positive electrode material containing graphite; a negative electrode material containing an oxide of at least one metal element selected from Ti, Zr, V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Zn, Sn, Sb, Bi, W and Ta, which may preferably contains a metal oxide containing at least Ti as a metal element; and an electrolyte solution. This storage device has high capacitance and high discharge voltage, thereby having high energy. Consequently, this storage device can have high energy density, while being excellent in cycle performances and rate performances.

Storage device

This invention provides a titanic acid compound-type electrode active material having a high battery capacity and, at the same time, having excellent cycle characteristics. The titanic acid compound exhibits an X-ray diffraction pattern corresponding to a bronze-type titanium dioxide except for a peak for a (200) plane and having a peak intensity ratio between the (001) plane and the (200) plane, i.e., I/I, of not more than 0.2. The titanic acid compound may be produced by heat dehydrating HTiOat a temperature in the range of 200 to 330&#xb0; C., by heat dehydrating HTiOat a temperature in the range of 250 to 650&#xb0; C., or by heat dehydrating HTiOat a temperature in the range of 200 to 600&#xb0; C.

There is provided a process comprising mixing a divalent copper oxide with a reducing agent in the presence of a complexing agent and a protective colloid in a liquid medium to thereby produce copper microparticles without formation of a univalent copper oxide from the divalent copper oxide. Further, there is provided a process comprising reducing a divalent copper oxide in the presence of a complexing agent and a protective colloid, such as a protein, to thereby form metallic copper microparticles, adding a protective colloid scavenger, such as a protease, to thereby remove the protective colloid and effect agglomeration of metallic copper microparticles, and filtering the mixture by means of a pressure filter, a vacuum filter, a suction filter, etc.

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Yokkaichi, Japan

Masatoshi Honma