Osaka Titanium Technologies Co.

Japan

Osaka Titanium Technologies Co.

Japan

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A negative electrode material powder for a lithium ion secondary battery having a conductive carbon film on the surface of a lower-silicon-oxide powder; wherein a specific surface area in BET measurement ranges from more than 0.3 m^(2)/g to 40 m^(2)/g, and no SiC peak appears at 2= 35.60.01 or the half-value width of the appeared peak is 2 or more in XRD measurement using CuK_() rays. The proportion of said carbon film preferably ranges from 0.2% to 2.5% by mass. Said powder preferably has 100000 cm or less of specific resistance. In XRD, P2/P1 < 0.01 is preferably satisfied between the highest value P1 of halo of SiO_(x) and a value P2 of the strongest linear peak of Si (111) above the halo. Accordingly, said powder can be used in the secondary battery with a large discharge capacity and a preferable cycle characteristics for practical use.


Provided is a negative-electrode material powder used for a lithium-ion secondary battery having a large discharge capacity and sufficient cycle characteristics as being durable in use. The powder for the battery includes a conductive carbon film on a lower silicon oxide powder, surface and satisfies requirements that: Si in SiC is 15.1 wt% or less in content, or A3 (=A2-A1) is 15.1 or less, given A1 (wt%): Si content measured by acid solution process, and A2 (wt%): Si content measured by alkali solution process; and a specific resistance is 30,000 cm or less. In the lower silicon oxide powder, a maximum value P1 of SiO_(x)-derived halos appearing at 2=10 to 30 and a value P2 of the strongest line peak of Si (111) appearing at 2=28.40.3, in XRD using CuK beam, preferably satisfy P2/P1<0.01. The content of tar component is preferably 1 ppm or more and 4,000 ppm or less.


Provided is a negative-electrode material powder for a lithium-ion secondary battery including a conductive carbon film on the surface of a silicon oxide powder, in which the total content of tar components is not less than 1 ppm and not more than 4000 ppm, and in the Raman spectrum, peaks exist at 1350 cm^(1 )and 1580 cm^(1), while the peak at 1580 cm^(1 )has a half-value width of not less than 50 cm^(1 )and not more than 100 cm^(1). In the negative-electrode material powder, a specific surface area is preferably not less than 0.3 m^(2)/g and not more than 40 m^(2)/g, and the proportion of the conductive carbon film is preferably not less than 0.2 mass % and not more than 10 mass %. This makes it possible to provide a negative-electrode material powder which can be used to obtain a lithium-ion secondary battery with large discharge capacity and satisfactory cycle characteristics.


Patent
OSAKA Titanium Technologies Co. | Date: 2012-04-25

Provided is a silicon oxide to be used for a negative electrode active material of a lithium-ion secondary battery, characterized in that: a g-value measured by an ESR spectrometer is in the range of not less than 2.0020 to not more than 2.0050; and given that A, B, and C are the area intensities of peaks near 420 cm^(-1), 490 cm^(-1) and 520 cm^(-1) respectively in a Raman spectrum measured by a Raman spectroscopy, A/B is not less than 0.5 and C/B is not more than 2. The silicon oxide is used as a negative electrode active material, whereby a lithium-ion secondary battery having excellent cycle characteristic and initial efficiency in addition to high capacity can be obtained. The silicon oxide preferably has a spin density in the range of not less than 110^(17) spins/g to not more than 510^(19) spins/g. A negative electrode material for lithium-ion secondary battery contains not less than 20% by mass of this silicon oxide as a negative electrode active material.


Provided is a negative-electrode material powder for a lithium-ion secondary battery including a conductive carbon film on the surface of a lower silicon oxide powder, in which the total content of tar components measured by TPD-MS is not less than 1 ppm by mass and not more than 4000 ppm by mass, and in the Raman spectrum, peaks exist at 1350 cm^(-1) and 1580 cm^(-1), while the peak at 1580 cm^(-1) has a half-value width of not less than 50 cm^(-1) and not more than 100 cm^(-1). In the negative-electrode material powder, a specific surface area measured by the BET method is preferably not less than 0.3 m^(2)/g and not more than 40 m^(2)/g, and the proportion of the conductive carbon film is preferably not less than 0.2 mass% and not more than 10 mass%. A specific resistance of the lower silicon oxide powder is preferably not more than 40000 cm, and a maximum value P1 of SiO_(x)-incurred halos and a value P2 of the strongest line peak of Si (111) preferably satisfy a relationship of P2/P1<0.01 in XRD measurement. This makes it possible to provide a negative-electrode material powder which can be used to obtain a lithium-ion secondary battery as being durable at practical level with large discharge capacity and satisfactory cycle characteristics.


Patent
OSAKA Titanium Technologies Co. | Date: 2012-07-18

Provided is a silicon oxide in the form of powder, which is used for a negative electrode active material of a lithium-ion secondary battery and is represented by SiO_(x), wherein, when the silicon oxide is measured by use of an X-ray diffractometer comprising a sealed tube light source as a light source and a high speed detector as a detector, a halo is detected at 20240, and a peak is detected at the highest quartz line position therein, and the height P1 of the halo and the height P2 of the peak at the highest quartz line position satisfy P2/P10.05. This silicon oxide is used as the negative electrode active material, whereby a lithium-ion secondary battery having stable initial efficiency and cycle characteristic can be obtained. The x of the SiO_(x) is preferably 0.7


Patent
OSAKA Titanium Technologies Co. | Date: 2012-08-29

Provided is a negative electrode active material for a lithium-ion secondary battery, comprising SiO_(x) that has an intensity ratio A_(1)/A_(2) of 0.1 or less in spectra measured by a Fourier transform infrared spectrometer after subjecting the SiO_(x) to evacuation treatment at 200C, given that A_(1) designates an intensity of a silanol group-derived peak which appears around 3400 to 3800 cm^(-1), and A_(2) designates an intensity of a siloxane bond-derived peak which appears around 1000 to 1200 cm^(-1). It is preferred that x in the SiO_(x) satisfies x<1; there is no sign of an Si-H bond-derived peak A_(3) that may normally exhibit around 2100 cm^(-1) in spectra of the SiO_(x) measured by a laser Raman spectrometer; and a ratio Y/X is 0.98 or less, given that X is a mole ratio of O to Si in the whole body of the SiO_(x), and Y is a mole ratio of O to Si in a surface vicinity of the SiO_(x). A lithium-ion secondary battery having high initial efficiency and charge/discharge capacity can be obtained by using this active material.


In a lithium ion secondary battery using a negative electrode material powder including a lower silicon oxide powder as a negative electrode material, a charge electric potential at 0.45-1.0 V relative to a Li reference upon initial charging results in a lithium ion secondary battery having a large discharge capacity with excellent cycle characteristics, which can be durable in practical use. On this occasion, the charge electric potential being 0.45-1.0 V relative to the Li reference upon initial charging means that an electric potential plateau caused by the generation of Li-silicate is observed, and the Li-silicate is uniformly generated in the negative electrode material. The negative electrode material powder according to the present invention having the charge electric potential of 0.45-1.0 V relative to the Li reference upon initial charging prevents the negative electrode material from being finely torn apart upon charging/discharging which results in cycle characteristic degradation, and excellent cycle characteristics are obtained. It is preferable for the negative electrode material powder according to the present invention to have an electrically conductive carbon film on the surface, and for the ratio of the electrically conductive carbon film to the surface of the powder to be 0.2-10 mass %.


Provided is a negative-electrode material powder for lithium-ion secondary battery including a silicon-rich layer on the surface of a lower silicon oxide powder, and a negative-electrode material powder for said battery comprising a silicon oxide powder, characterized by satisfying c/d<1, where c is the molar ratio of oxygen to silicon on the surface of the silicon oxide powder and d is that for the entire part thereof. It preferably satisfies one of c<1 and 0.8


Provided is SiO_(x), wherein the amount of generated H_(2)O gas detected in a temperature range of 200 to 800C in a temperature-programmed desorption gas analysis is 680 ppm or less. The amount of the generated H_(2)O is desirably 420 ppm or less. In addition, in a graph obtained by X-ray diffraction, the peak intensity P1 at a Si peak point exhibited near 2 = 28 and the base intensity P2 at a peak point interpolated from the gradient of average intensities in the fore and aft positions near the peak point desirably satisfy (P1-P2)/P20.2. This SiO_(x) is used as a vapor deposition material, whereby the generation of splashing is suppressed in forming a film, and a vapor-deposited film having excellent gas barrier properties can be formed. In addition, this SiO_(x) is used as a negative electrode active material, whereby high initial efficiency of a lithium-ion secondary battery can be maintained.

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