Mitsui Minings & Melting Co., Ltd.

Daisuke Inoue

Shinya Kagei

Hitohiko Ide

Yanko Marinov Todorov

Yoshimi Hata

Tetsuya Mitsumoto

Hideaki Matsushima

Yasunori Tabira

Natsumi Shibamura

Daisuke Washida

Toshikazu Matsuyama

Takuya Yamamoto

Jaime W Dumont

Arrelaine A Dameron

Barbara K Hughes

An active material includes a core portion, and a coating portion arranged on a surface of the core portion. The core portion contains elemental lithium (Li), elemental manganese (Mn), and elemental oxygen (O). The coating portion contains an element A (A is at least one selected from the group consisting of Ti, Zr, Ta, Nb, and Al) and elemental oxygen (O). W/(T×S) is more than 0 and 15% by mass/(cm/g) or less, wherein T (nm) represents an average thickness of the coating portion, S (m/g) represents a specific surface area of the active material, and W (% by mass) represents an amount of element A contained in the coating portion.

Active material and process for producing the same

Provided is a novel negative electrode for nonaqueous electrolyte secondary batteries, which is capable of improving cycle characteristics and is also capable of suppressing aggregation of active material particles in a slurry. The negative electrode active material for nonaqueous electrolyte secondary batteries contains silicon and has a D50 of 0.1 &#x3bc;m to 5 &#x3bc;m, and an amount of water measured at 120&#xb0; C. to 300&#xb0; C. by the Karl-Fischer method (referred to as 'amount of water') per specific surface area (referred to as 'CS'), that is, the amount of water/CS, of 0.1 to 80 ppm/(m/cc).

Negative electrode active material for nonaqueous electrolyte secondary batteries

Proposed is a novel negative electrode for nonaqueous electrolyte secondary batteries in which the battery capacity does not decrease even when charging and discharging are repeated. Proposed is a silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries, comprising negative electrode active material particles which are provided with a surface layer containing carbon and titanium or aluminum on the entirety or a portion of the surface of the active material.

A positive electrode active material comprising a lithium metal composite oxide having a layered crystal structure provides a novel lithium metal composite oxide powder which can suppress the reaction with an electrolytic solution and raise the charge-discharge cycle ability of a battery, and can improve the output characteristics of a battery. A lithium metal composite oxide powder comprises a particle having a surface portion where one or a combination of two or more ('surface element A') of the group consisting of Al, Ti and Zr is present, on the surface of a particle comprising a lithium metal composite oxide having a layered crystal structure, wherein the amount of surface LiOH is smaller than 0.10% by weight, and the amount of surface LiCOis smaller than 0.25% by weight; in an X-ray diffraction pattern, the ratio of an integral intensity of the (003) plane of the lithium metal composite oxide to that of the (104) plane thereof is higher than 1.15; and the amount of S obtained by a measurement using ICP is smaller than 0.10% by weight of the lithium metal composite oxide powder (100% by weight).

Lithium metal composite oxide powder

The present invention relates to a positive electrode active material including a lithium metal composite oxide having a layer crystal structure, and provides a novel positive electrode active material for a lithium secondary cell, which can suppress the reaction with an electrolyte solution and can raise the charge-discharge cycle ability of the cell, and can make good the output characteristics of the cell. There is proposed a positive electrode active material for a lithium secondary cell, including an active particle having a surface portion where one or a combination of two or more (these are referred to as 'surface element A') of the group consisting of Al, Ti and Zr is present, on a surface of a particle including a lithium metal composite oxide having a layer crystal structure and represented by the general formula: Li1+xM1&#x2212;xO2 (wherein M is one or a combination of two or more (these are referred to as 'constituent element M') of the group consisting of Mn, Co, Ni, transition elements of from the third group elements to the 11th group elements of the periodic table, and typical elements up to the third period of the periodic table), wherein the ratio (CA/CM) of a concentration CA of the surface element A to a concentration CM of the constituent element M is higher than 0 and lower than 0.8, as measured by XPS; the amount of surface lithium impurity is smaller than 0.40% by weight; and in an X-ray diffraction pattern measured by XRD, the ratio (003)/(104) of an integral intensity of the peak originated from the (003) plane to an integral intensity of the peak originated from the (104) plane is higher than 1.15.

Positive electrode active material for lithium secondary cell

A negative electrode active material for nonaqueous secondary batteries is disclosed. The active material contains a silicon solid solution having one or more than one of a group 3 semimetal or metal element, a group 4 semimetal or metal element except silicon, and a group 5 nonmetal or semimetal element incorporated in silicon as a solute element. The solute element is present more on the crystal grain boundaries of the silicon solid solution than inside the grains.

In order to propose a new negative electrode for nonaqueous electrolyte secondary batteries having excellent dispersibility even with a negative electrode active material having a relatively small particle size, there is proposed a negative electrode active material for nonaqueous electrolyte secondary batteries, the negative electrode active material containing silicon and having negative electrode active material particles that have a D50 based on a volume-based particle size distribution obtainable by measurement by a laser diffraction scattering type particle size distribution analysis method, of 0.1 &#x3bc;m to 5.0 &#x3bc;m, and include a surface layer containing oxygen, silicon and carbon on the entire surface or a portion of the active material surface.

A negative electrode active material for nonaqueous secondary batteries containing a silicon solid solution. The silicon solid solution has one or more than one of a group 3 semimetal or metal element, a group 4 semimetal or metal element except silicon, and a group 5 nonmetal or semimetal element incorporated in silicon. The solid solution shows an XRD pattern in which the position of the XRD peak of the solid solution corresponding to the XRD peak position assigned to the (422) plane of silicon shifts to the smaller or greater angle side relative to the position of the XRD peak assigned to the (422) plane of silicon peak by 0.1&#xb0; to 1&#xb0;. The solid solution has a lattice strain of 0.01% to 1% as determined by XRD.

Growing community of inventors

Ageo, Japan

Daisuke Inoue