Sumitomo Metal Mining Company, Ltd.

Toyota Jidosha Kabushiki Kaisha

Willy Shun Kai Bong

Tetsutaro Hayashi

Yuji Yamamoto

Yoshinari Makimura

Momoko Procter

Toshihiro Kato

Shinsuke Suganuma

To provide a positive electrode active material capable of further reducing positive electrode resistance and exhibiting better output characteristics. A positive electrode active material includes a coating layer formed of a metal composite oxide of Li and one or more metal elements selected from Al, Ti, Zr, Nb, Mo, and W on at least a part of a surface of lithium transition metal-containing composite oxide particles, and has d50 of 3.0 to 7.0 μm, a BET specific surface area of 2.0 to 5.0 m/g, a tap density of 1.0 to 2.0 g/cm, and an oil absorption amount of 30 to 60 ml/100 g, in which the amount of metal elements other than Li contained in the coating layer is 0.1 to 1.5 atom % with respect to the total number of atoms of Ni, Mn, and Co contained in the composite oxide particles.

Positive electrode active material for lithium ion secondary battery and lithium ion secondary battery

A positive electrode active material includes lithium transition metal-containing composite oxide particles containing an additive element M1 and includes a coating layer formed of a metal composite oxide of Li and a metal element M2 on a part of a surface of the particles. The particles have a d50 of 3.0 to 7.0 μm, a BET specific surface area of 2.0 to 5.0 m/g, a tap density of 1.0 to 2.0 g/cm, and an oil absorption amount of 30 to 60 ml/100 g. For each of a plurality of primary particles having a primary particle size within a range of 0.1 to 1.0 μm among the primary particles, a coefficient of variation of the concentration of M1 is 1.5 or less, and the amount of M2 is 0.1 to 1.5 atom % with respect to the total number of atoms of Ni, Mn, and Co contained in the composite oxide particles.

A positive electrode active material is constituted by lithium transition metal-containing composite oxide particles having a layered rock salt type crystal structure and are composed of secondary particles each formed of an aggregation of primary particles. The secondary particles have a d50 of 3.0 to 7.0 μm, a BET specific surface area of 1.8 to 5.5 m/g, a pore peak diameter of 0.01 to 0.30 μm, and a log differential pore volume [dV/d(log D)] of 0.2 to 0.6 ml/g within a range of the pore peak diameter. In each of a plurality of primary particles having a primary particle size of 0.1 to 1.0 μm, a coefficient of variation of the concentration of an additive element M is 1.5 or less.

The present disclosure can bring excellent output characteristics to a nonaqueous electrolyte secondary battery that uses a cathode active material containing tungsten while desired durability is secured. The battery of the present disclosure includes a cathode, an anode, and a nonaqueous electrolyte. The cathode includes a cathode active material layer that contains a granular cathode active material. The cathode active material includes a core part that contains a lithium-transition metal composite oxide of a layered structure; a tungsten-concentrated layer that is formed over a surface of the core part and has a higher tungsten concentration than in the core part; and a lithium-tungsten compound particle that adheres to at least part of a surface of the tungsten-concentrated layer and contains tungsten and lithium. In the battery of the present disclosure, the tungsten-concentrated layer has an amorphous structure. This can bring excellent output characteristics while desired durability is secured.

Nonaqueous electrolyte secondary battery

A non-aqueous electrolyte secondary battery that has a low initial resistance and an increase in resistance after charging and discharging is suppressed. The secondary battery includes a positive electrode, a negative electrode, and a non-aqueous electrolyte. The positive electrode includes a positive electrode active substance layer, which contains a lithium composite oxide having a layered structure. The lithium composite oxide is a porous particle. A surface of the porous particle includes a layer having a rock salt type structure. A thickness of the layer is not less than 5 nm and not more than 80 nm. A void ratio of the porous particle is not less than 15% and not more than 48%. The porous particle contains two or more voids having diameters that are at least 10% of the particle diameter of the porous particle. The surface of the porous particle includes a coating of lithium tungstate.

Non-aqueous electrolyte secondary battery including a positive electrode active substance containing a lithium composite oxide porous particle and a rock salt layer

A non-aqueous electrolyte secondary battery is obtained using a lithium composite oxide having a layered structure in a positive electrode active substance. An increase in resistance following repeated charging and discharging is suppressed. The battery includes a positive electrode provided with a positive electrode active substance layer, a negative electrode and a non-aqueous electrolyte. The positive electrode active substance layer contains a porous particle lithium composite oxide having a layered structure. The average void ratio of the porous particle is not less than 12% but not more than 50%, and it contains two or more voids having diameters that are at least 8% of its particle diameter. The surface of the porous particle is provided with a coating of lithium tungstate. The coverage ratio of the surface of the porous particle by the lithium tungstate is not less than 10% but not more than 65%.

Non-aqueous electrolyte secondary battery including a positive electrode active substance containing a lithium composite oxide porous particle having voids

A non-aqueous electrolyte secondary battery which is obtained using a lithium composite oxide having a layered structure and coated with a tungsten-containing compound in a positive electrode active substance, and which has a low initial resistance, and in which an increase in resistance following repeated charging and discharging is suppressed. The non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode and a non-aqueous electrolyte. The positive electrode includes a positive electrode active substance layer containing a lithium composite oxide having a layered structure. The lithium composite oxide includes a porous particle having a void ratio of not less than 20% but not more than 50%. The porous particle contains two or more voids having diameters that are at least 10% of the particle diameter of the porous particle. The surface of the porous particle is provided with a coating containing tungsten oxide and lithium tungstate.

Nonaqueous electrolyte secondary battery including a positive electrode active substance containing a lithium composite oxide porous particle having voids

Provided is a nonaqueous electrolyte secondary battery with a positive electrode active material that contains an excess of Li and has a layered structure, the nonaqueous electrolyte secondary battery having a high output and enabling prevention of gelation of the positive electrode active material layer-forming paste during production. The herein disclosed nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes a positive electrode active material layer. The positive electrode active material layer contains a lithium composite oxide having a layered structure as a positive electrode active material. The compositional ratio of the lithium atom to the metal atom other than a lithium atom contained in the lithium composite oxide is greater than 1. The lithium composite oxide is in the form of porous particles. Each of the porous particles has at least two voids each of which has the percentage of a void area with respect to the area occupied by each of the particles in a cross-sectional view thereof of at least 1%. Each of the porous particles is provided with a coating of lithium tungstate on a surface thereof.

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Niihama, Japan

Willy Shun Kai Bong