Hitachi, Ltd.

Other

Hitachi Chemical Company, Ltd.

Shin-kobe Electric Machinery Co., Ltd.

Seiji Takeuchi

Yasushi Muranaka

Tatsuo Horiba

Hidetoshi Honbo

Yoshito Ishii

Hideto Momose

Kazunori Fujita

Yasuhisa Aono

Junya Kaneda

Noriyuki Watanabe

Tomoichi Kamo

Kazuo Iwamoto

Teruo Kumagai

Kouichi Takei

Kunko Kitami

Hisao Yamashita

Fumito Nakajima

Katsuya Ebara

Kohki Tamura

Yoshinori Takata

Shuko Yamauchi

Mamoru Taki

Kyoko Honbo

Masanori Yoshikawa

Takahiro Yamaki

Takeo Yamagata

Ikuo Shimokobe

Eiji Hoshi

Yoshimasa Hamano

Kouki Tamura

A lithium secondary battery, which comprises a positive electrode, a negative electrode containing a lithium ion-storable/dischargeable negative electrode-active material and a lithium ion conductive, non-aqueous electrolytic solution or polymer electrolyte can have distinguished charging/discharging characteristics and a higher safety, when the negative electrode material contains particles comprising carbonaceous materials and at least one of elements capable of forming a compound with Li; the elements have a melting point of at least 900&#xb0; C. and a thermal expansion coefficient of not more than 9 ppm/K at room temperature; the particles are embedded in a plurality of layers of the carbonaceous materials; the particles being subjected to a mechanical treatment to make particle sizes of the particles smaller than the initial particle size in advance.

Lithium secondary battery, and process for producing the same

Objects of the present invention is to provide a carbon material having a superior reversibility in lithium intercalation-deintercalation reaction, and a non-aqueous secondary battery using the carbon material as an active material for a negative electrode, which has a high energy density and an excellent rapid charging and discharging characteristics. Graphite powder having a maximum particle diameter of less than 100 &#x3bc;m and an existing fraction of rhombohedral structure in the crystalline structure of less than 20% is used as an active material for the negative electrode of the non-aqueous secondary battery. The graphite powder can be obtained by pulverizing raw graphite with a jet mill, and subsequently treating the powder at a temperature equal to or higher than 900&#xb0; C.

Non-aqueous secondary battery having negative electrode including graphite powder

A lead-acid battery superior in high-efficiency charging characteristic to conventional lead-acid batteries and a carbon material used in the lead-acid battery having excellent charge acceptability are disclosed. The lead-acid battery uses, as an additive to the anode active material, a simple substance and/or compound thereof, both having a catalysis for desulfurization or a catalyst for SOoxidation by adding to, or loading on, a carbon material such as active carbon, carbon black, or the like. When the lead-acid battery with an anode containing carbon material is applied to electric cars, various hybrid cars, power storage systems, elevators, electromotive tools and power source systems such as uninterruptible power source, distributed power source and the like, all having high input and output requirements, stable control can be obtained.

Lead-acid battery

Provided is a carbon material having a superior reversibility in lithium intercalation-deintercalation reaction, and a non-aqueous secondary battery using the carbon material as an active material for a negative electrode, which has a high energy density and an excellent rapid charging and discharging characteristics. Graphite powder having a maximum particle diameter of less than 100 &mgr;m and an existing reaction of rhombohedral structure in the crystalline structure of less than 20% is used as an active material for the negative electrode of the non-aqueous secondary battery. The graphite powder can be obtained by pulverizing raw graphite with a jet mill, and subsequently treating the powder at a temperature equal to or higher than 900&deg;C.

Non-aqueous secondary battery and a method of manufacturing graphite powder

A lithium secondary battery comprising a positive electrode, a negative electrode containing a lithium ion-storable/dischargeable negative electrode-active material and a lithium ion conductive, non-aqueous electrolytic solution or polymer electrolyte, characterized in that the negative electrode-active material comprises particles of carbonaceous material and particles of metal and metal oxide capable of enhancing lithium ion interstitial diffusibility/releasability as embedded in the particles of carbonaceous material, particles of carbonaceous materials and lithium ion interstitially diffusible/releasable particles being prepared by carbonization of a mixture thereof with MA or carbon precursor, has a high capacity and a long cycle life, and can be used in various electric appliances.

Lithium secondary battery having oxide particles embedded in particles of carbonaceous material as a negative electrode-active material

A lithium secondary battery, which comprises a positive electrode, a negative electrode containing a lithium ion-storable/dischargeable negative electrode-active material and a lithium ion conductive, non-aqueous electrolytic solution or polymer electrolyte can have distinguished charging/discharging characteristics and a higher safety, when the negative electrode material contains particles comprising carbonaceous materials and at least one of elements capable of forming a compound with Li; the elements have a melting point of at least 900&deg; C. and a thermal expansion coefficient of not more than 9 ppm/K at room temperature; the particles are embedded in a plurality of layers of the carbonaceous materials; the particles being subjected to a mechanical treatment to make particle sizes of the particles smaller than the initial particle size in advance.

A carbon material is provided having a superior reversibility in lithium intercalation-deintercalation reaction, and a non-aqueous secondary battery is provided which uses the carbon material as an active material for a negative electrode, which has a high energy density and an excellent rapid charging and discharging characteristics. Graphite powder having a maximum particle diameter of less than 100 &mgr;m and an existing fraction of rhombohedral structure in the crystalline structure of less than 20% is used as an active material for the negative electrode of the non-aqueous secondary battery. The graphite powder can be obtained by pulverizing raw graphite with a jet mill, and subsequently treating the powder at a temperature equal to or higher than 900&deg; C.

A lithium secondary battery suitable for use as a power source for a secondary battery using system such as an electric automobile, motor bicycle or portable equipment includes a negative electrode (17) composed of a carbon material including carbon particles carrying fine particles of a metal which forms an alloy with lithium. The carbon particles have a face-to-face dimension which is 3.354 to 3.369 .ANG. and a crystal grain size in a C-axis direction which is equal to or greater than 300 .ANG.. The metal forming an alloy with lithium has a particle size which is equal to or smaller than 1000 .ANG.. With the use of the charge/discharge capacity of an alloy of the metal and lithium, a value exceeding the theoretical capacity 372 mAh/g of graphite can be obtained. The lithium secondary battery is capable of discharge with an output energy density equal to or higher than 350 W/kg.

Secondary battery using system and material for negative electrode of

A lithium secondary battery having a high energy density, a long life, a low cost, an improved safety and a high output density uses a high crystalline carbon or an amorphous carbon bearing fine particles of a metal which forms an alloy with lithium, and a metal which does not form any alloy with lithium, in the range of 5-10% by weight, as a material for the negative electrode thereof.

Lithium secondary battery having negative electrode of carbon material

A fuel cell electrode having a catalyst layer comprising electroconductive particles carrying a catalytically active component and a binder on a water-repellent baked plate comprising a carbon paper comprising carbon fiber and an organic binder and polytetrafluoroethylene infiltrated into voids of said carbon paper, characterized in that the carbon fiber of said baked plate has at least 20 cutting edges per square millimeter, and said polytetrafluoroethylene is infiltrated into at least one of said cutting edges to render the plate flexible.

Flexible, water-repellent baked carbon plate, its production, fuel cell

In a fuel cell having a fuel electrode, an oxidant electrode, and an electrolyte which is located between both the electrodes, a methanol concentration control device is disposed, at a pipe which supplies the fuel to the fuel cell for controlling the amount of the methanol in the pipe by detecting the open-circuit voltage of the unit cell or the open-circuit potential of the oxidant cell at the methanol concentration control device.

Fuel cell comprising a device for detecting the concentration of methanol

An inorganic ion-exchanger supported on a carrier suitable for recovery of useful resources in sea water, removal of impurities from high temperature boiler water in nuclear reactors or industrial boilers, removal of impurities in industrial waste water, etc. is prepared by supporting an active component of inorganic ion exchanger, such as hydrous oxide of metal, for example, titanium, zirconium, etc. on a porous carrier such as alumina, silica, or activated carbon, where a pH of a solution in contact with the active component and the carrier is adjusted so that the active component and the carrier can have zeta potentials of opposite polarities to each other, and an inorganic ion-exchanger having a larger amount of the supported active component and firmly supporting less bleedable active component can be obtained by setting out a supporting condition on the basis of the polarity of zeta potential.

Method for supporting hydrous metal oxide on carrier

The separation of constituents is carried out in such a way that a mixed amino acid sample is supplied to a separation column packed with a cation exchange resin and that, during the analysis of the single sample, five sorts of elutes of different compositions are supplied to the separation column in succession and by stages. The pH of the elute at the second stage is held higher than that of the elute at the first stage, and the pH's of the elutes at the third to fifth stages are held successively higher. However, the pH of the elute at the third stage is held lower than that of the elute at the second stage. On the other hand, the concentrations of counter ions contained in the elutes at the first to fifth stages are held successively higher inversely to the order in which the elutes are supplied. Notwithstanding that the pH of the elute at the third stage is lowered, the broadening of a component peak can be prevented by the increase of the counter ion concentration. Moreover, the analytical time is shortened as a whole.

Method of ion exchange chromatography

A sample containing a plurality of components to be analyzed is introduced to a separation column at its top through a sample feeding device. The sample thus introduced is separated to the individual components in the separation column. Ion exchange resins capable of undergoing deformation depending upon an applied pressure are filled in the separation column. An eluting solution containing sodium ions is fed to the separation column at its top under a pressure of 40 kg/cm.sup.2 or higher through a feed pump. Components leaving the separation column at its bottom are detected by a detector. After the components have left the separation column, a regenerating solution containing lithium ions is introduced to the separation column at its bottom, and is made to leave the separation column at its top. The ion exchange resins are regenerated by passing the regenerating solution through the separation column, and a separation for another sample is made ready thereby. Another sample is then introduced into the separation column at its bottom and the separated components of the sample are made to leave the separation column at its top.

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Hitachiota, Japan

Seiji Takeuchi