This positive electrode active material for nonaqueous electrolyte secondary batteries contains: a lithium transition metal composite oxide having secondary particles, each of which is formed of aggregated primary particles; and a surface modification layer which is formed on the surface of each primary particle of the lithium transition metal composite oxide. The lithium transition metal composite oxide contains at least Al and 80% by mole or more of Ni relative to the total number of moles of the metal elements excluding Li; and the surface modification layer contains at least Ba, and at least one of Sr and Ca.

A positive electrode active material, a method for producing the same, and a positive electrode and a lithium secondary battery in including the same are disclosed herein. In some embodiments, a method of producing a positive electrode active material includes mixing a lithium transition metal oxide and a carbon-based material having a hollow structure to form a mixture, and mechanically treating the mixture to form a carbon coating layer on the surface of the lithium transition metal oxide, wherein the carbon-based material has a chain shape, and has a specific surface area of 500 m.sup.2/g or greater, a graphitization degree (I.sub.D/I.sub.G) of 1.0 or higher, and a dibutylphthalate (DBP) absorption of 300 mL/100 g or greater.

The present invention provides coated metal sulfide particles comprising a metal sulfide that is partially or totally coated with a coating layer containing a metal oxide, the metal sulfide having a composition ratio of sulfur to a metal (S/M.sup.1) of 2.1 to 10 in terms of the molar ratio. The coated metal sulfide particles are a material that improves charge-and-discharge cycle characteristics without reducing the initial capacity.

A titanium-niobium oxide achieves suppressed adulteration with TiO.sub.2 and Ti.sub.2Nb.sub.10O.sub.29 and suppressed growth of crystal grains, and an electrode and a lithium-ion secondary cell include such a titanium-niobium oxide. The titanium-niobium oxide contains less than 0.30 at % of an alkali metal element and at least one element selected from the group consisting of Al, Y, La, Ce, Pr, and Sm. A ratio of thea total atomic weight of Al, Y, La, Ce, Pr, and Sm to thea total atomic weight of Ti and Nb is equal to or more than 0.001.

A method of producing a positive electrode active material, the method includes: contacting first particles that contain a lithium transition metal composite oxide with a solution containing sodium ions to obtain second particles containing the lithium transition metal composite oxide and sodium element, wherein the lithium transition metal composite oxide has a layered structure and a composition ratio of a number of moles of nickel to a total number of moles of metals other than lithium in a range of from 0.7 to less than 1; mixing the second particles and a boron compound to obtain a mixture; and heat-treating the mixture at a temperature in a range of from 100° C. to 450° C.

The present invention relates to a positive electrode active material which is formed such that a lithium ion diffusion path in a lithium composite oxide constituting a positive electrode active material is directed to a specific crystal plane, and has improved electrochemical properties and stability by improving the growth of the crystal plane to which the lithium ion diffusion path is directed, and a lithium secondary battery using the same.

A cathode active material for a lithium secondary battery includes a lithium-transition metal composite oxide particle having a single particle shape, and a first coating layer formed on a surface of the lithium-transition metal composite oxide particle. The first coating layer includes a La—Zr—O compound. Life-span and capacity properties are improved by a combination of the lithium-transition metal composite oxide particle having the single particle shape and the first coating layer formed thereon.

The present invention relates, in general terms, to methods of forming activated carbon. The method of forming activated carbon comprises mixing carbon black with an activation catalyst and heating the carbon black in order to form the activated carbon. The present invention also relates to applications of activated carbon as disclosed herein. In a preferred embodiment, the activation catalyst is selected from ammonium persulfate, sodium persulfate, potassium persulfate or a combination thereof.

Semiconductor nanoparticles including Ag, In, Ga, and S are provided. In the semiconductor nanoparticles, a ratio of a number of Ga atoms to a total number of In and Ga atoms is 0.95 or less. The semiconductor nanoparticles emit light having an emission peak with a wavelength in a range of from 500 nm to less than 590 nm, and a half bandwidth of 70 nm or less, and have an average particle diameter of 10 nm or less.

The invention relates to an encapsulated metal particle comprising a core encapsulated in a shell, wherein the core comprises a metallic substance, and wherein the shell comprises a insulating substance. The invention also relates to a polymer composition comprising a plurality of the encapsulated metal particles, a mixture comprising a plurality of encapsulated metal particles and plurality of polymer particles, and the use of the encapsulated metal particle as an additive for increasing the thermal conductivity and/or radio frequency (RF) conductivity of a matrix substance such as an adhesive.