Disclosed are a transition metal precursor for preparation of a lithium transition metal oxide, in which a ratio of tap density of the precursor to average particle diameter D50 of the precursor satisfies the condition represented by Equation 1 below, and a lithium transition metal oxide prepared using the same. $\begin{array}{cc}0<\frac{\mathrm{Tap}\mathrm{density}}{\begin{array}{c}\mathrm{Average}\mathrm{particle}\mathrm{diameter}D50\\ \mathrm{of}\mathrm{transition}\mathrm{of}\mathrm{metal}\mathrm{precursor}\end{array}}<3500\left(g/\mathrm{cc}.Math.\mathrm{cm}\right)& \left(1\right)\end{array}$

Disclosed are a transition metal precursor for preparation of a lithium transition metal oxide, in which a ratio of tap density of the precursor to average particle diameter D50 of the precursor satisfies the condition represented by Equation 1 below, and a lithium transition metal oxide prepared using the same. $\begin{array}{cc}0<\frac{\mathrm{Tap}\mathrm{density}}{\begin{array}{c}\mathrm{Average}\mathrm{particle}\mathrm{diameter}D50\\ \mathrm{of}\mathrm{transition}\mathrm{of}\mathrm{metal}\mathrm{precursor}\end{array}}<3500\left(g/\mathrm{cc}.Math.\mathrm{cm}\right)& \left(1\right)\end{array}$

Provided are a positive electrode active material for a lithium secondary battery, a method of preparing the same, and a lithium secondary battery including the same.

According to an exemplary embodiment, a positive electrode active material for a lithium secondary battery which includes lithium metal oxide particles and a coating layer placed on at least a part of a surface of the lithium metal oxide particles may be provided, wherein the coating layer includes B, LiOH, Li.sub.2CO.sub.3, and Li.sub.2SO.sub.4.

Disclosed herein are a nickel oxide fine powder that is suitable as a material for electronic parts and has a controlled sulfur content, a low chlorine content, and a fine particle size and a method for industrially and stably producing such a nickel oxide fine powder.

Nickel hydroxide obtained by neutralizing an aqueous nickel sulfate solution with an alkali is heat-treated in a non-reducing atmosphere at a temperature higher than 650° C. but lower than 1050° C. to form nickel oxide particles, and a sintered compact of nickel oxide particles that may be formed during the heat treatment is pulverized by preferably allowing the nickel oxide particles to collide with one another. The thus obtained nickel oxide fine powder has a sulfur content of 400 mass ppm or less, a chlorine content of 50 mass ppm or less, a sodium content of 100 mass ppm or less, and a specific surface area of 3 m.sup.2/g or more but less than 6 m.sup.2/g.

Disclosed herein are a nickel oxide fine powder that is suitable as a material for electronic parts and has a controlled sulfur content, a low chlorine content, and a fine particle size and a method for industrially and stably producing such a nickel oxide fine powder.

Nickel hydroxide obtained by neutralizing an aqueous nickel sulfate solution with an alkali is heat-treated in a non-reducing atmosphere at a temperature higher than 650° C. but lower than 1050° C. to form nickel oxide particles, and a sintered compact of nickel oxide particles that may be formed during the heat treatment is pulverized by preferably allowing the nickel oxide particles to collide with one another. The thus obtained nickel oxide fine powder has a sulfur content of 400 mass ppm or less, a chlorine content of 50 mass ppm or less, a sodium content of 100 mass ppm or less, and a specific surface area of 3 m.sup.2/g or more but less than 6 m.sup.2/g.

The production method is a method for producing a positive electrode active material for a lithium ion secondary battery which contains at least nickel and lithium, the method including: a firing process in which a mixture of a nickel compound powder and a lithium compound powder is fired; and a water washing process in which a lithium-nickel composite oxide powder obtained in the firing process is washed with water, wherein the firing process is performed under conditions such that a value obtained by dividing a ratio of an amount-of-substance of lithium to a total amount-of-substance of transition metals other than lithium in the lithium-nickel composite oxide powder after the washing with water by a ratio of an amount-of-substance of lithium to a total amount-of-substance of transition metals other than lithium in the lithium-nickel composite oxide powder before the washing with water exceeds 0.95.

The production method is a method for producing a positive electrode active material for a lithium ion secondary battery which contains at least nickel and lithium, the method including: a firing process in which a mixture of a nickel compound powder and a lithium compound powder is fired; and a water washing process in which a lithium-nickel composite oxide powder obtained in the firing process is washed with water, wherein the firing process is performed under conditions such that a value obtained by dividing a ratio of an amount-of-substance of lithium to a total amount-of-substance of transition metals other than lithium in the lithium-nickel composite oxide powder after the washing with water by a ratio of an amount-of-substance of lithium to a total amount-of-substance of transition metals other than lithium in the lithium-nickel composite oxide powder before the washing with water exceeds 0.95.

A process for preparing a lithium nickel metal oxide is provided. The process comprises a step of high-energy milling a mixture of a nickel source, a lithium source and at least one additional metal source to form a high-energy milled intermediate, and subsequently calcining the high-energy milled intermediate to form the lithium nickel metal oxide.

An optical glass has a refractive index (n.sub.d) of 1.64 or more. A P value represented by the following formula (1) is in a range of 7.0<P value<10.0: P value=log(A.sub.450×P.sub.450+A.sub.550×P.sub.550+A.sub.650×P.sub.650+A.sub.750×P.sub.750) (1). A.sub.450, A.sub.550, A.sub.650 and A.sub.750 are absorbances of the optical glass with a plate thickness of 10 mm at a wavelength of 450 nm, 550 nm, 650 nm and 750 nm, respectively. P.sub.450, P.sub.550, P.sub.650 and P.sub.750 are radiances of light having a wavelength of 450 nm, 550 nm, 650 nm and 750 nm, respectively, at 1,300° C. according to Planck's radiation law. All of internal transmittances in terms of a 10-mm thickness at wavelengths of 450 nm, 550 nm, 650 nm and 750 nm are 91% or more.

An optical glass has a refractive index (n.sub.d) of 1.64 or more. A P value represented by the following formula (1) is in a range of 7.0<P value<10.0: P value=log(A.sub.450×P.sub.450+A.sub.550×P.sub.550+A.sub.650×P.sub.650+A.sub.750×P.sub.750) (1). A.sub.450, A.sub.550, A.sub.650 and A.sub.750 are absorbances of the optical glass with a plate thickness of 10 mm at a wavelength of 450 nm, 550 nm, 650 nm and 750 nm, respectively. P.sub.450, P.sub.550, P.sub.650 and P.sub.750 are radiances of light having a wavelength of 450 nm, 550 nm, 650 nm and 750 nm, respectively, at 1,300° C. according to Planck's radiation law. All of internal transmittances in terms of a 10-mm thickness at wavelengths of 450 nm, 550 nm, 650 nm and 750 nm are 91% or more.