Sanyo Electric Co., Ltd.

Hitachi Chemical Company, Ltd.

Yoshihiro Shoji

Koji Nishio

Toshihiko Saito

Mikiya Yamasaki

Toshiyuki Nohma

Yasuyuki Kusumoto

Mayumi Uehara

Yuji Yamamoto

Seiji Yoshimura

Tatsuya Nishida

Masayuki Terasaka

Nobuhiro Nishiguchi

Hideyuki Inomata

Kouichi Takei

Hiroshi Nakagawa

Kiyoshi Suzuki

Keiichi Tsujioku

Katsuya Imai

Minoru Fujimoto

In order to provide a nonaqueous electrolyte secondary battery negative electrode material that has an excellent discharging capacity, the charge/discharge efficiency and the charge load characteristics, a manufacturing method thereof, a nonaqueous electrolyte secondary battery negative electrode with the negative electrode material and a nonaqueous electrolyte secondary battery, the invention provides a nonaqueous electrolyte secondary battery negative electrode material including graphite particles that have a block-like structure where a plurality of flat graphite fine particles assembles or bonds non-parallel with each other, the aspect ratio of 5 or less and a volume of fine pores in the range of 10 to 10nm in a volume of 400 to 2000 cm/kg; and a layer of carbon formed on a surface of the graphite particle, wherein a ratio (by weight ratio) of the layer of carbon to the graphite particle is in the range of 0.001 to 0.01, a manufacturing method thereof, a nonaqueous electrolyte secondary battery negative electrode with the negative electrode material and a nonaqueous electrolyte secondary battery.

Non-aqueous electrolyte secondary battery-use cathode material, production method therefor, non-aqueous electrolyte secondary battery-use cathode and non-aqueous electrolyte secondary battery using the cathode material

The present invention is directed to a non-aqueous electrolyte battery comprising an anode, a cathode using a carbon material, and a non-aqueous electrolytic solution, wherein the carbon material obtained by coating a core composed of graphitized carbon in which spacing (d.sub.002) of lattice planes (002) is in the range of 3.35 to 3.39 .ANG. and the length (Lc) of a crystallite in the direction of the c axis is not less than 1000 .ANG. with coating graphitized carbon in which spacing (d.sub.002) of lattice planes (002) is more than that in the graphitizing carbon and is in the range of 3.36 to 3.48 .ANG., the carbon material obtained by coating a core composed of graphitized carbon in which spacing (d.sub.002) of lattice planes (002) is in the range of 3.35 to 3.39 .ANG. with a calcined product of an organic substance composed of carbon containing sulfur atoms, or the carbon material composed multi-phase graphitized carbon having two or more crystals respectively different crystallinities in one particle, the length (Lc) of a crystallite in the direction of the c axis in each of the crystals being not less than 10 .ANG., are used for the cathode.

Non-aqueous electrolyte battery

Disclosed is a nonaqueous electrolyte secondary battery including a negative electrode prepared by coating a substrate with a slurry comprising a carbon material, an alkali metal salt of carboxymethylcellulose, and a styrene-butadiene rubber and drying it, the alkali metal salt accounting for 0.5.about.2 weight % of the total weight of the carbon material, styrene-butadiene rubber, and CMC alkali metal salt. Because of the higher electrical conductivity of the CMC alkali metal salt used as the thickening agent than the conventional carboxymethylcellulose or its ammonium salt, the secondary battery of the invention including the above negative electrode has an excellent load characteristic.

Nonaqueous electrolyte secondary battery

A nonaqueous electrolyte battery comprises a positive electrode, a negative electrode with lithium as active material, a nonaqueous electrolyte comprising a solute and a solvent, and a separator, the nonaqueous electrolyte further comprising 3.times.10.sup.-4 to 3.times.10.sup.-2 mole/liter, preferably 1.5.times.10.sup.-3 to 6.times.10.sup.-3 mole/liter of a specific calcium salt. This battery, with the nonaqueous electrolyte incorporating the specific calcium in the specific amount, causes little self-discharge during storage, thus having excellent storage stability.

Nonaqueous electrolyte battery comprising a non-aqueous electrolyte with

A nonaqueous electrolyte battery comprising a positive electrode, a negative electrode having lithium as an active material, a nonaqueous electrolyte comprising a solute and a solvent, and a separator. The solvent is a mixed solvent consisting essentially of 5 to 50% by volume of cyclic carbonate, 5 to 50% by volume of chain carbonate and 40 to 80% by volume of ether. The mixed solvent of a specific composition is less likely to cause undesirable surface layer formation on the negative electrode so that the electric resistance of the interface between the negative electrode and nonaqueous electrolyte is kept small. The nonaqueous electrolyte battery of the invention can therefore deliver a large amount of current and provide a high discharge capacity at low temperatures.

Nonaqueous electrolyte battery

A lithium secondary battery comprises a negative electrode having lithium as an active material, a positive electrode comprising a boron-containing lithium-manganese composite oxide as an active material and a nonaqueous electrolyte comprising a solute and a solvent, the boron-containing lithium-manganese composite oxide having an atomic ratio between B and Mn (B/Mn) of 0.01 to 0.20 and an average valence of manganese before charge-discharge of at least 3.80, and the solvent being a mixed solvent containing 5 to 50% by volume of a butylene carbonate. This battery is highly reliable, since the positive electrode active material minimally decomposes and hence the internal resistance minimally increases, even when the battery is continuously charged at a high voltage by mistake.

Lithium secondary battery

A nonaqueous electrolyte battery comprises a positive electrode comprising a mixture of manganese dioxide and a fluorinated graphite as a positive electrode active material, a negative electrode comprising lithium metal or a substance capable of occluding and discharging lithium ion as a negative electrode material, and a nonaqueous electrolyte, said fluorinated graphite being represented by the formula (CFx)n wherein 1.2.ltoreq..times..ltoreq.1.4 and contained in said mixture in a ratio by weight of 0.1 to 4%. This battery undergoes minimal self discharge and has excellent storage capability, since reaction products formed by reaction of manganese dioxide and the nonaqueous electrolyte used minimally react with lithium on the negative electrode side.

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Hirakata, Japan

Yoshihiro Shoji