Seimi Chemical Co., Ltd.

Agc Seimi Chemical Co., Ltd.

Sumitomo Chemical Company, Limited

Megumi Uchida

Naoshi Saito

Manabu Suhara

Takeshi Kawasato

Kazushige Horichi

Koji Tatsumi

Tokumitsu Kato

Remi Hiraki

Takuya Mihara

Yukimitsu Wakasugi

Toshiaki Abe

Satoshi Takamatsu

Kunihiko Terase

To provide a cathode active material for a lithium ion secondary battery, which has high packing properties and high volume capacity density, and a method for its production. A cathode active material for a lithium ion secondary battery is used, which comprises a mixture B of a collection of many large particles having different particle sizes and a collection of many small particles having different particle sizes, wherein the function F(x) of a particle size x of a particle contained in the mixture B and its frequency F has a relation of the formula 1, the function E(x) of a particle size x of a particle contained in a mixture B' after the mixture B is pressed and its frequency E has a relation of the formula 2, the rate of change of the median size &#x3bc;&#x2032;relative to &#x3bc;is at most 10%, and the rate of change of the median size &#x3bc;&#x2032;relative to &#x3bc;is at least 20%, 

Cathode active material for lithium ion secondary battery, and method for its production

A process for producing a lithium-containing composite oxide for a positive electrode active material for use in a lithium secondary battery, the oxide having the formula LiQNMOF(wherein Q is at least one element selected from the group consisting of titanium, zirconium, niobium and tantalum, N is at least one element selected from the group consisting of Co, Mn and Ni, M is at least one element selected from the group consisting of Al, alkaline earth metal elements and transition metal elements other than Q and N, 0.9&#x2266;p&#x2266;1.1, 0&#x2266;q&#x3c;0.03, 0.97&#x2266;x&#x2266;1.00, 0&#x2266;y&#x3c;0.03, 1.9&#x2266;z&#x2266;2.1, q+x+y=1 and 0&#x2266;a&#x2266;0.02), which comprises firing a mixture of a lithium, Q element source and N element sources, and an M element source and/or fluorine source when these elements are present, in an oxygen-containing atmosphere, wherein the Q element source is a Q element compound aqueous solution having a pH of from 0.5 to 11.

Process for producing lithium-containing composite oxide for positive electrode for lithium secondary battery

The present invention provides a lithium-containing composite oxide for a positive electrode for a lithium secondary battery, which has a large volume capacity density and high safety, and excellent durability for charge and discharge cycles and charge and discharge rate property, and its production method. The lithium-containing composite oxide is represented by the general formula LiNMOF(where N is at least one element selected from the group consisting of Co, Mn and Ni, M is at least one element selected from the group consisting of Al, Sn, alkaline earth metal elements and transition metal elements other than Co, Mn and Ni, 0.9&#x2266;p&#x2266;1.2, 0.965&#x2266;x&#x3c;2.00, 0&#x3c;y&#x2266;0.035, 1.9&#x2266;z&#x2266;4.2, and 0&#x2266;a&#x2266;0.05), wherein when a powder of the lithium-containing composite oxide is classified into small particles with an average particle size of 2 &#x3bc;m&#x2266;Ds&#x2266;8 &#x3bc;m and large particles with an average particle size of 10 &#x3bc;m&#x2266;Dl&#x2266;25 &#x3bc;m, a content of the small particles is from 15 to 40% by weight and a content of the large particles is from 60 to 85% by weight, and 0.01&#x2266;ys&#x2266;0.06, 0&#x2266;yl&#x2266;0.02 and 0&#x2266;yl/ys&#x3c;1, where (ys) is a ratio of the M element in the above general formula in the small particles and (yl) is a ratio of the M element in the general formula in the large particles.

Lithium-containing composite oxide and its production method

To provide a process for producing a surface modified lithium-containing composite oxide, which is excellent in discharge capacity, volume capacity density, safety, durability for charge and discharge cycles and an excellent rate property, at a low production cost. The present invention is characterized in that a process for producing a surface modified lithium-containing composite oxide, wherein a lithium titanium composite oxide is contained in the surface layer of particles of a lithium-containing composite oxide represented by the formula: LiNMOF, where N is at least one element selected from the group consisting of Co, Mn and Ni, M is at least one element selected from the group consisting of Al, Sn, alkaline earth metal elements and transition metal elements other than Co, Mn and Ni, 0.9&#x2266;p&#x2266;1.3, 0.9&#x2266;x&#x2266;2.0, 0&#x2266;y&#x2266;0.1, 1.9&#x2266;z&#x2266;4.2, and 0&#x2266;a&#x2266;0.05, which comprises impregnating a solution having a lithium source and a titanium source dissolved therein, followed by heat treatment at a determined temperature, to obtain the surface modified lithium-containing composite oxide, wherein the titanium contained in the surface layer is from 0.01 to 1.95 mol %.

Process for production of cathode active material for lithiun ion secondary battery

A process for producing a lithium-containing composite oxide for a positive electrode active material for use in a lithium secondary battery, the oxide having the formula LiNMOF(wherein N is at least one element selected from the group consisting of Co, Mn and Ni, M is at least one element selected from the group consisting of Al, alkaline earth metal elements and transition metal elements other than N, 0.9&#x2266;p&#x2266;1.2, 0.9&#x2266;x&#x3c;1.00, 0&#x3c;m&#x2266;0.03, 1.9&#x2266;z&#x2266;2.2, x+m=1 and 0&#x2266;a&#x2266;0.02), which comprises using as an M element source a solution comprising a complex containing the M element dissolved in an organic solvent.

A positive electrode active material for a lithium secondary battery containing a lithium-cobalt composite oxide is produced by firing, as a cobalt source, a mixture of substantially spherical cobalt hydroxide or tricobalt tetraoxide having such a sharp particle size distribution that the average particle size D50 is from 7 to 20 &#x3bc;m, and cobalt oxyhydroxide having an average particle size of secondary particles formed by agglomeration of primary particles of from 7 to 20 &#x3bc;m, in a proportion of from 5:1 to 1:5 as the cobalt atomic ratio, at a temperature of from 700&#xb0; C. to 1050&#xb0; C. in an oxygen-comprising atmosphere.

Process for positive electrode active substance for lithium secondary battery

To provide a cathode active material for a lithium secondary battery, which is low in gas generation and has high safety and excellent durability for charge and discharge cycles even at a high charge voltage. A process for producing a lithium-containing composite oxide represented by the formula LiLNMOF(wherein L is at least one element selected from the group of B and P, N is at least one element selected from the group consisting of Co, Mn and Ni, M is at least one element selected from the group consisting of Al, alkaline earth metal elements and transition metal elements other than N, 0.9&#x2266;p&#x2266;1.1, 1.0&#x2266;q&#x3c;0.03, 0.97&#x2266;x&#x3c;1.00, 0&#x2266;y&#x2266;0.03, 1.9&#x2266;z&#x2266;2.1, q+x+y=1 and 0&#x2266;a&#x2266;0.02), wherein a lithium-containing composite oxide powder containing an N element and, if necessary, an M element and fluorine, is preliminarily prepared; the lithium-containing composite oxide powder is mixed with an aqueous solution containing the L element source; from the obtained mixture, an aqueous medium is removed, followed by the firing in an oxygen-containing atmosphere at from 300 to 1,050&#xb0; C.

A positive electrode active material is produced by firing, as a cobalt source, a mixture of a) substantially spherical large particle size cobalt hydroxide or tricobalt tetraoxide having a sharp particle size distribution, and b) small particle size cobalt hydroxide or tricobalt tetraoxide, in a proportion of from 9:1 to 1:2 as the cobalt atomic ratio, at a temperature of from 700&#xb0; C. to 1050&#xb0; C. in an oxygen-comprising atmosphere.

Positive electrode active substance for lithium secondary battery and process for producing the same

To provide a process for producing a lithium-containing composite oxide for a positive electrode of a lithium secondary battery, which has a large volume capacity density, high safety, excellent durability for charge and discharge cycles and excellent low temperature characteristics.

Lithium-containing composite oxide and its production process

The present invention provides a positive electrode, which has a large volume capacity density, high safety, and is excellent in the coating uniformity, the charge and discharge cyclic durability and the low-temperature properties. Further, the present invention provides a process for producing a lithium-cobalt composite oxide for a positive electrode for a lithium secondary cell, the lithium-cobalt composite oxide being represented by the formula LiCoMOF(wherein M is a transition metal element other than Co, aluminum or an alkaline earth metal element, 0.9&#x2266;p&#x2266;1.1, 0.980&#x2266;x&#x2266;1.000, 0&#x2266;y&#x2266;0.02, 1.9&#x2266;z&#x2266;2.1, x+y=1 and 0&#x2266;a&#x2266;0.02).

Process for producing a lithium-cobalt composite oxide for a positive electrode for a lithium secondary cell

A process to produce a positive electrode active material for a lithium secondary battery, having a large volume capacity density and high safety, uniform coating properties, charge and discharge cyclic durability and low temperature characteristics even at a high charge voltage is disclosed. The positive electrode active material is a lithium-containing composite oxide represented by the formula LiNMOF, wherein N is at least one element selected from the group consisting of Co, Mn and Ni, M is at least one element selected from the group consisting of Sn, Zn, Al, alkaline earth metal elements, and transition metal elements other than the N element, O.9&#x2266;p&#x2266;l.1, 0.97&#x2266;x&#x2266;l.00, 0&#x2266;y&#x2266;0.03, 1.9&#x2266;z&#x2266;2.1, x+y=1 and 0&#x2266;a&#x2266;0.02. The N element source powder having an average particle size of from 2 to 20 &#x3bc;m, is impregnated with the M element salt aqueous solution, and the prepared dry powder comprising the N element, M element, a lithium source and optionally a fluorine source is fired at from 700 to 1 ,050&#xb0; C. in an oxygen-containing atmosphere.

To provide a process for producing a lithium-cobalt composite oxide for a positive electrode of a lithium secondary battery, which has a large volume capacity density, high safety, high charge and discharge cycle durability, high press density and high productivity. A process for producing a lithium-cobalt composite oxide represented by the formula LiCoMOF(wherein M is a transition metal element other than Co, or an alkaline earth metal element, 0.9&#x2266;p&#x2266;1.1, 0.980&#x2266;x&#x2266;1.000, 0&#x2266;y&#x2266;0.02, 1.9&#x2266;z&#x2266;2.1, x+y=1, and 0&#x2266;a&#x2266;0.02), characterized in that as a cobalt source, a mixture is used which comprises cobalt hydroxide in the form of substantially spherical secondary particles with an average particle size of from 8 to 20 &#x3bc;m formed by agglomeration of primary particles and tricobalt tetroxide in the form of secondary particles with an average particle size of from 2 to 10 &#x3bc;m formed by agglomeration of primary particles, in a cobalt atomic ratio of from 5:1 to 1:5, and firing is carried out at from 700 to 1,050&#xb0; C.

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Chigasaki, Japan

Megumi Uchida