The present invention relates to a positive electrode active material and a lithium secondary battery comprising the same.

The present invention provides a nanostructured titanic acid salt and a preparation process and use thereof. The process comprises preparing a dispersion containing titanium peroxy complex; slowly adding a metal compound to the dispersion containing the titanium peroxy complex to form a solution; adding an alcohol to the solution under normal temperature and normal pressure to produce the nanostructured titanic acid salt precursor precipitate in the solution, and separating the precipitate to obtain the titanic acid salt precursor; drying the precursor, and then heat treating it to obtain the nanostructured titanic acid salt product. The present invention provides a process for preparing a titanic acid salt with simple preparation process, easy control for process parameters and easy large-scale industrial production.

A process for preparing a titanic acid salt, titanic acid, and titanium oxide having a controllable particle size and a hierarchical structure, wherein the process includes the steps of: preparing a titanium-containing peroxo-complex solution; adding a basic metal compound to the titanium-containing peroxo-complex solution to form a mixture solution; adding one of polyvinyl alcohol, hydroxypropyl methyl cellulose, and polyethylene glycol to the mixture solution to form a precursor dispersion; and subjecting the precursor dispersion to a solvothermal reaction to obtain the titanic acid salt having a hierarchical structure. The process for preparing a titanic acid salt, titanic acid, and titanium oxide having a controllable particle size and a hierarchical structure, can not only realize the regulation of morphology and particle diameter of constituent units in the hierarchical structure, but also can achieve the regulation of particle size in the hierarchical structure.

Provided is an alkali metal titanate which, when used as a constituent material of a friction material, is excellent in heat resistance and friction force and capable of effectively suppressing wear of a mating material disposed to face the friction material. The alkali metal titanate includes a sodium atom and a silicon atom. The content of the sodium atom is 2.0 to 8.5 mass %. The content of the silicon atom is 0.2 to 2.5 mass %. The ratio of the content of an alkali metal atom other than the sodium atom to the content of the sodium atom is 0 to 6.

The solid electrolyte material consists essentially of Li, Ti, M, and F. Here, M is at least one selected from the group consisting of Mg and Ca.

An object of the present invention is to provide composite particles capable of suppressing oxidation over time of a Si—C composite material. Composite particles (B) of the present invention contains composite particles (A) containing carbon and silicon; and amorphous layers coating surfaces thereof, where the composite particles (B) have I.sub.Si/I.sub.G of 0.10 or more and 0.65 or less, and have R value (I.sub.D/I.sub.G) of 1.00 or more and 1.30 or less, when a peak due to silicon is present at 450 to 495 cm.sup.−1, an intensity of the peak is defined as I.sub.Si, an intensity of a G band (peak intensity in the vicinity of 1600 cm.sup.−1) is defined as I.sub.G, and an intensity of a D band (peak intensity in the vicinity of 1360 cm.sup.−1) is defined as I.sub.D in a Raman spectrum, and where the composite particles (B) have a full width at half maximum of a peak of a 111 plane of Si of 3.0 deg. or more using a Cu-Kα ray in an XRD pattern.

A positive electrode active material for obtaining a lithium ion secondary battery, wherein capacity, electron conductivity, durability, and heat stability at the time of overcharge are improved, durability and heat stability being achieved at a high level, and including: a lithium nickel manganese composite oxide composed of secondary particles, in which a plurality of primary particles are flocculated, wherein the composite oxide is represented by a general formula (1): Li.sub.dNi.sub.1-a-b-cMn.sub.aM.sub.bTi.sub.cO.sub.2 (wherein, M is at least one kind of element selected from Co, W, Mo, V, Mg, Ca, Al, Cr, Zr and Ta, 0.05≤a≤0.60, 0≤b≤0.60, 0.02≤c≤0.08, 0.95≤d≤1.20), at least a part of titanium in the composite oxide is solid-solved in the primary particles, and, a lithium titanium compound exists on a surface of the positive electrode active material for the lithium ion secondary battery.

A lithium titanate/titanium niobate core-shell composite material includes a core which comprises lithium titanate; and a shell which is cladded over the core and comprises titanium niobate. A preparation method of lithium titanate/titanium niobate core-shell composite material includes (A) mixing lithium titanate powder and titanium niobate powder; and (B) granulating the mixture produced by step (A) through a spray granulation process to obtain a lithium titanate/titanium niobate composite material with titanium niobate cladding over lithium titanate. The lithium titanate/titanium niobate core-shell composite material and the preparation method thereof can be applied to a battery.

This document describes processes for preparing ceramics, especially lithium-based ceramics. The ceramics produced by this process and their use in electrochemical applications are also described as well as electrode materials, electrodes, electrolyte compositions, and electrochemical cells comprising them.

A method for manufacturing a dense layer that includes: supplying a substrate and a suspension of non-agglomerated nanoparticles of a material P; depositing a layer on the substrate using the suspension; drying the layer thus obtained; and densifying the dried layer by mechanical compression and/or heat treatment. The method is characterised in that the suspension of non-agglomerated nanoparticles of material P includes nanoparticles of material P having a size distribution having a value of D50. The distribution includes nanoparticles of material P of a first size D1 between 20 nm and 50 nm, and nanoparticles of material P of a second size D2 characterised by the value D50 being at least five times less than that of D1, or the distribution has a mean size of nanoparticles of material P less than 50 nm, and a standard deviation to mean size ratio greater than 0.6.