There is provided a method of manufacturing silica microspheres includes the steps of mixing acid and water to form a mixture; adding a silicon alkoxide to the mixture so as to precipitate microspheres; allowing the microspheres to settle into a sediment and removing a supernatant liquid; and immersing the microspheres in acid.

A negative electrode active material includes a carbon material, where the carbon material has a specific degree of graphitization and aspect ratio distribution. A degree of graphitization Gr of the carbon material measured by an X-ray diffraction analysis method is 0.82 to 0.92, and based on a total quantity of particles of the carbon material, a proportion of particles with an aspect ratio greater than 3.3 in the carbon material is less than 10%. The negative electrode active material helps to improve cycle performance of the electrochemical apparatus. FIG. 1.

The present invention provides a silicon-silicon composite oxide-carbon composite, a method for preparing same, and a negative electrode active material for a lithium secondary battery, comprising same. More particularly, the silicon-silicon composite oxide-carbon composite of the present invention has a core-shell structure wherein the core comprises silicon, a silicon oxide compound, and magnesium silicate, and the shell comprises a carbon layer. In addition, by having a specific range of span values through the adjustment of particle size distribution of the composite, when used as a negative electrode active material of a secondary battery, the composite can improve not only the capacity of the secondary battery but also the cycle characteristics and initial efficiency thereof.

Provided is alumina material comprising alumina and zirconium, wherein in a radial distribution function obtained by Fourier-transforming an extended X-ray absorption fine structure (EXAFS) spectrum of a K absorption edge of the zirconium in the alumina material, the value of I.sub.B/I.sub.A is 0.5 or less where I.sub.A is a maximum intensity among the intensities of peaks present at 0.1 nm to 0.2 nm, and I.sub.B is a maximum intensity among the intensities of peaks present at 0.28 nm to 0.35 nm.

Provided is a method of preparing a sparsely pillared organic-inorganic hybrid compound. The method of preparing an organic-inorganic hybrid compound includes: preparing a compound having a gibbsite structure by a method other than a hydrothermal synthesis method, using a trivalent metal cation source, an alkali imparting agent, and a first solvent (S10); and preparing an organic-inorganic hybrid compound by a method other than a hydrothermal synthesis method, using the compound of the gibbsite structure, a divalent metal cation source, dicarboxylic acid, and a second solvent (S20).

In one embodiment, a positive electrode active material for a secondary battery, the positive electrode active material being a primary particle having a monolithic structure that includes a lithium composite metal oxide of Formula 1 below, wherein the primary particle has an average particle size (D.sub.50) of 2 μm to 20 μm and a Brunauer-Emmett-Teller (BET) specific surface area of 0.15 m.sup.2/g to 0.5 m.sup.2/g, and wherein the positive electrode active material has a rolling density of 3.0 g/cc or higher under a pressure of 2 ton.Math.f:
Li.sub.aNi.sub.1-x-yCo.sub.xM1.sub.yM3.sub.zM2.sub.wO.sub.2  [Formula 1] in Formula 1, M1 is at least one selected from the group consisting of Al and Mn, M2 is any one or two or more elements selected from the group consisting of Zr, Ti, Mg, Ta, and Nb, M3 is any one or two or more elements selected from the group consisting of W, Mo, and Cr, and 1.0≤a≤1.5, 0≤x≤0.5, 0≤y≤0.5, 0.005≤z≤0.01, 0≤w≤0.04, 0<x+y≤0.7.

A preparation method of a composite anode material of micrometer-sized carbon-coated silicon and carbon includes: subjecting micrometer-sized silicon particles to a chemical vapor deposition reaction under a gas atmosphere containing carbon to obtain carbon-coated first micrometer-sized silicon particles; dispersing the carbon-coated first micrometer-sized silicon particles in a first mixed solvent to obtain a dispersed solution; adding alkali into the dispersed solution and heating the dispersed solution to obtain carbon-coated second micrometer-sized silicon particles; dispersing the carbon-coated second micrometer-sized silicon particles and graphene oxide in a second mixed solvent that are subjected to a hydrothermal reaction to obtain a composite hydrogel of reduced graphene oxide, silicon, and carbon; and heating the hydrogel to obtain the composite anode material.

Disclosed are a process and continuous system for producing LiPF.sub.6, and a prepared mixture crystal, composition, electrolyte solution and lithium ion battery containing LiPF.sub.6. During preparation, a first feed stream containing PF5 and a second feed stream containing LiF and HF are introduced into a first microchannel reactor, a gas part of a product in the first microchannel reactor is introduced into a second microchannel reactor to react with a third feed stream containing LiPF.sub.6, LiF and HF, and a liquid part of the product in the first microchannel reactor is subjected to crystallization and drying to obtain LiPF.sub.6. The LiPF.sub.6 has the advantages of a high purity, a uniform particle size, a high product quality stability, etc., and is suitable for use as a component of an electrolyte solution of a lithium ion battery.

A method includes positioning a porous structure in a pressure cell; injecting an inert pressure medium within the pressure cell; and pressurizing the pressure cell to a pressure that thermodynamically favors a crystalline phase of the porous structure over an amorphous phase of the porous structure to transition the amorphous phase of the porous structure into the crystalline phase of the porous structure.

A cathode active material for a lithium secondary battery includes lithium transition metal oxide particles, wherein the lithium transition metal oxide particles may include first lithium transition metal oxide particles (first particles) including an interparticular pore and second lithium transition metal oxide particles (second particles) having an average particle diameter within a range of a diameter of the interparticular pore, measured by mercury intrusion porosimetry. By including first particles including an interparticular pore and second particles having an average particle diameter within a range of a diameter of the interparticular pore measured by mercury intrusion porosimetry, the cathode active material may have a reduced interparticular pore present therein. Accordingly, the cathode active material may have an improved pellet density. Consequently, when a lithium secondary battery is manufactured using the cathode active material, the energy density thereof may improve.