Sanyo Electric Co., Ltd.

Nobumichi Nishida

Shinya Miyazaki

Shin Fujitani

Masatoshi Takahashi

Hiroshi Watanabe

Masato Iwanaga

Satoshi Yamamoto

Hiroshi Nakajima

Ryuji Ohshita

Hiroyuki Fujimoto

Kentaro Takahashi

Akira Kinoshita

Yukihiro Oki

Takuya Morimoto

Hidetoshi Inoue

Yoshihiko Ikeda

Shuji Tsutsumi

A non-aqueous electrolyte secondary battery with excellent discharge cycle characteristics and a charging termination potential ranging from 4.4 to 4.6 V based on lithium, consisting of a positive electrode comprising a positive electrode active material, a negative electrode, and a non-aqueous electrolyte containing a non-aqueous solvent and an electrolyte salt, in which the positive electrode active material comprises a mixture of a lithium-cobalt composite oxide containing at least both zirconium and magnesium in LiCoO, and a lithium-manganese-nickel composite oxide having a layered structure and containing at least both manganese and nickel, and the potential of the positive electrode active material ranges from 4.4 to 4.6 V based on lithium, and the non-aqueous electrolyte contains at least one of aromatic compounds selected from the group consisting at least of toluene derivatives, anisole derivatives, biphenyl, cyclohexyl benzene, tert-butyl benzene, tert-amyl benzene, and diphenyl ether.

Non-aqueous electrolyte secondary battery

The preservation performance of a nonaqueous electrolyte secondary cell charged to high potential is improved while the initial capacity and the cycle property of the cell are also improved. The nonaqueous electrolyte secondary cell includes: a positive electrode having lithium phosphate and a positive electrode active material containing lithium cobalt compound oxide and lithium manganese nickel compound oxide having a layer structure, the lithium cobalt compound oxide having at least zirconium and magnesium added in LiCoO; a negative electrode having a negative electrode active material; and a nonaqueous electrolyte having a nonaqueous solvent and an electrolytic salt. The potential of the positive electrode is more than 4.3 V and 5.1 V or less based on lithium. The nonaqueous electrolyte contains vinylene carbonate as the nonaqueous solvent and, as the electrolytic salt, at least one of lithium bis(pentafluoroethane sulfonyl)imide and lithium bis(trifluoromethane sulfonyl)imide at 0.1 M or more and 0.5 M or less. The nonaqueous electrolyte contains 1,3-dioxane.

High-voltage charge type nonaqueous electrolyte secondary cell

The present invention aims to provide a non-aqueous electrolyte secondary cell having high capacity and capable of preventing elution of cobalt and decomposition of the electrolyte. This aim can be accomplished by providing a non-aqueous electrolyte secondary cell comprising a positive electrode having a positive electrode active material, an negative electrode having an negative electrode active material, and non-aqueous electrolyte, wherein the positive electrode active material comprises lithium cobalt oxide to which at least one material selected from the group consisting of Mg, Al, Ti, and Zr was added, and the positive electrode comprises lithium phosphate.

Non-aqueous electrolyte secondary cell

The present invention improves the cycle characteristics of a non-aqueous electrolyte secondary cell that uses lithium cobalt oxide as a positive electrode active material. To this end, an element different from cobalt such as zirconium and titanium is added to the lithium cobalt oxide, acting as the positive electrode active material. The non-aqueous electrolyte contains a non-aqueous solvent containing diethyl carbonate at 10 to 30 volume percent on a base of 25 degree Celsius and contains an electrolyte salt.

Non-aqueous electrolyte lithium ion secondary cell with improved cycle characteristics and method for fabricating the same

In a nonaqueous electrolytic secondary battery according to the invention, hexagonal system lithium containing cobalt composite oxide having a crystallite size in a (110) vector direction of 1000 &#x212b; or more and having a halogen compound added thereto by burning at time of synthesis is used as a positive electrode active material. By measuring a pH value of a filtrate obtained by dispersing, in water, the lithium containing cobalt composite oxide having the halogen compound added thereto by the burning at time of the synthesis and a crystallite size in the (110) vector direction of 1000 &#x212b; or more, a value of 9.6 to 10.1 is obtained. By using the lithium containing cobalt composite oxide as a positive electrode active material, a high temperature cycle property can be enhanced.

Nonaqueous electrolytic secondary battery and method of manufacturing the same

The invention provides a non-aqueous electrolyte secondary cell that has high capacity and excels in cycle characteristics. The non-aqueous electrolyte secondary cell functions stably at a high potential of from 4.4 to 4.6 V with respect to lithium and inhibits the decomposition of the electrolytic solution at high potential. This is accomplished as follows. The non-aqueous electrolyte secondary cell has a positive electrode having a positive electrode active material; a negative electrode having a negative electrode active material; and a non-aqueous electrolyte having a non-aqueous solvent and electrolytic salt. The positive electrode active material has: lithium cobalt compound oxide having added therein at least zirconium and magnesium; and lithium-nickel-manganese compound oxide having a layered structure. The positive electrode active material has a potential of from 4.4 to 4.6 V with respect to lithium. The non-aqueous solvent contains diethyl carbonate of 10 vol. % or higher at 25&#xb0; C.

Nonaqueous electrolyte secondary cell and method for charging same

A positive electrode used in the non-aqueous electrolyte secondary battery of the present invention includes a hexagonal system lithium-containing cobalt composite oxide represented by the general expression &#x250c;LiCoMO(M=Zr, Mg, Al)&#x2518; obtained by synthesizing a lithium compound as a lithium source with a cobalt compound as a cobalt source to which 0.01 mol % or more and 1.0 mol % or less of zirconium is added and magnesium and/or aluminum is added through coprecipitation, as the positive electrode active material, whereby the thermal stability, load performance and charging/discharging cycle performance characteristics of the non-aqueous electrolyte secondary battery are improved without lowering its capacity and charging/discharging efficiency.

Non-aqueous electrolyte secondary battery and method of manufacturing the same

The present invention provides a nonaqueous electrolyte secondary cell having a positive electrode comprising mainly of a positive electrode active material, a negative electrode, and a nonaqueous electrolyte. The positive electrode active material is a lithium-containing transition metal composite oxide of a hexagonal crystal system that includes a compound represented by the general formula LiCoMO, where M is at least one species selected from the group consisting of V, Cr, Fe, Mn, Ni, Al, and Ti, and x is a decimal number in a range 0&#x3c;x&#x3c;1, magnesium, and halogen. In a nonaqueous electrolyte secondary cell having such a construction, the high-temperature characteristics are improved without reducing the cell capacity.

Nonaqueous electrolyte secondary cell and method of manufacturing the same

In a non-aqueous electrolyte secondary cell having a positive electrode mainly composed of a positive electrode active material, a negative electrode, and a non-aqueous electrolyte, the positive electrode active material includes a lithium-containing transition metal complex oxide represented with hexagonal structure by the general formula LiCo M O , wherein M is at least one element selected from the group consisting of V, Cr, Fe, Mn, Ni, Al, and Ti, and a crystallite size (110) of the lithium-containing transition metal complex oxide is greater than 1000 &angst;. Thereby, the thermal stability of the positive electrode active material is increased, and the discharge characteristic and the charge-discharge characteristic of the cell are improved.

Non-aqueous electrolyte secondary cell with a lithium cobalt oxide positive electrode

A rechargeable lithium battery has a positive electrode, a negative electrode and a non-aqueous electrolyte. The positive or negative electrode contains, as its active material, a complex oxide comprising a material represented by the compositional formula M Ti O and including an anatase-form crystal structure phase, wherein M is at least one metallic element selected from V, Mn, Fe, Co, Ni, Mo and Ir and x satisfies the relationship 0<x&lE;0.11. Lithium may further be added to the complex oxide.

Rechargeable lithium battery

A rechargeable lithium battery is disclosed having a positive electrode, a negative electrode and a non-aqueous electrolyte. The positive or negative electrode contains, as its active material, an Li&mdash;Ti complex oxide having a spinel crystal structure and represented by the compositional formula Li M Ti O , wherein M is at least one element selected from V, Nb, Mo and P and x satisfies the relationship 0<x&lE;0.45.

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Tokushima, Japan

Nobumichi Nishida