The present invention relates to a positive electrode active material and a lithium secondary battery including the same, and more particularly, to a positive electrode active material, which includes an overlithiated lithium manganese-based oxide, which is a solid solution with a phase belonging to a C2/m space group and a phase belonging to an R3-m space group and in which stability degradation caused by excessive amounts of lithium and manganese in the lithium manganese-based oxide is mitigated and/or prevented because there are regions with different proportions of the phase belonging to the C2/m space group and the phase belonging to the R3-m space group in the lithium manganese-based oxide, and a lithium secondary battery including the same.

A method for producing a nanocomposite sorbent comprising carbon nanotube-grafted acrylic acid/acrylamide copolymer which involves copolymerization of acrylic acid and acrylamide in the presence of an aqueous dispersion of carbon nanotubes. The method yields a nanocomposite sorbent material having a reversible adsorption capacity phenol of 5 to 2500 μg of phenol per mg of nanocomposite sorbent. Also disclosed is a method for removing organic pollutants from water using the nanocomposite sorbent.

A method for producing aluminum oxide is provided. The method uses an aluminum-oxide-forming agent containing a partially hydrolyzed aluminum alkyl compound containing an aluminum trialkyl or a mixture thereof, and a solvent. It is thus possible to produce an aluminum oxide thin film or aluminum oxide particles on or in a substrate that is not resistant to polar solvents. A method of producing a polyolefin-based polymer nanocomposite containing zinc oxide particles or aluminum oxide particles using a solution containing a partially hydrolyzed zinc alkyl or a solution containing a partially hydrolyzed aluminum alkyl is also provided. The polyolefin-based polymer nanocomposite contains a polyolefin substrate and zinc oxide particles or aluminum oxide particles, and does not contain a dispersant. The zinc oxide particles or aluminum oxide particles have an average particle size of less than 100 nm.

A method of preparing metal nanoparticles using a fungal extract includes providing an aqueous solution including a metal salt; and combining the fungal extract with the aqueous metal salt solution to produce the metal nanoparticles. The fungal extract can be an aqueous extract of the manglicolous fungi The metal salt can be copper sulfate (CuSO.sub.4) and the metal nanoparticles can be copper nanoparticles. The metal nanoparticles can have a mean diameter in the range of from about 5 nm to about 100 nm. The copper nanoparticles can be used as an antimicrobial agent.

A method for producing a nanocomposite sorbent comprising carbon nanotube-grafted acrylic acid/acrylamide copolymer which involves copolymerization of acrylic acid and acrylamide in the presence of an aqueous dispersion of carbon nanotubes. The method yields a nanocomposite sorbent material having a reversible adsorption capacity phenol of 5 to 2500 μg of phenol per mg of nanocomposite sorbent. Also disclosed is a method for removing organic pollutants from water using the nanocomposite sorbent.

We provide ZnO nanoporcupines and a coating comprising ZnO nanoporcupines. Each nanoporcupine comprises a ZnO stem attached by one end to said surface, and a plurality of ZnO nanospikes attached to and extending away from the surface of the stem, the nanospikes being spread across the surface of the stem. The nanoporcupines and coating have antibacterial properties. We also provide a method of producing the nanoporcupine/coating comprising the steps of immersing a surface with ZnO stem precursors in a reaction mixture comprising hexamethylenetetramine, up to about 1 mM of L-ascorbic acid, and up to about 1 mM of a zinc salt in deionized water, and heating the reaction mixture at a temperature between about 90° C. and about 95° C. to produce the ZnO nanoporcupines on the surface.

Silver nanoparticles made by a green synthesis method using silver nitrate and a chlorophyll derivative, such as a chlorophyllin are provided. The thus produced silver nanoparticles can have a crystalline structure and an average particle size ranging from about 10 nm to about 40 nm. The disclosed silver nanoparticles may be useful in treating, preventing, and/or reducing insect infestation of a variety of plants, particularly date palms.

A method for producing aluminum oxide is provided. The method uses an aluminum-oxide-forming agent containing a partially hydrolyzed aluminum alkyl compound containing an aluminum trialkyl or a mixture thereof, and a solvent. It is thus possible to produce an aluminum oxide thin film or aluminum oxide particles on or in a substrate that is not resistant to polar solvents. A method of producing a polyolefin-based polymer nanocomposite containing zinc oxide particles or aluminum oxide particles using a solution containing a partially hydrolyzed zinc alkyl or a solution containing a partially hydrolyzed aluminum alkyl is also provided. The polyolefin-based polymer nanocomposite contains a polyolefin substrate and zinc oxide particles or aluminum oxide particles, and does not contain a dispersant. The zinc oxide particles or aluminum oxide particles have an average particle size of less than 100 nm.

A positive electrode active material for a secondary battery according to an embodiment of the present invention comprises a lithium composite oxide represented by chemical formula 1 below and containing a layer-structured lithium excess oxide, wherein the lithium composite oxide comprises a secondary particle; the secondary particle comprises at least one primary particle; the primary particle comprises at least one crystallite; at least any one selected from the secondary particle, the primary particle, and the crystallite comprises a core and a shell occupying at least a portion of the surface of the core; and when the crystal structure belonging to space group C2/m is designated as [C2/m], the crystal structure belonging to space group R-3m is designated as [R-3m], and the ratio of the crystal structure belonging to space group C2/m versus the crystal structure belonging to space group R-3m is designated as [C2/m]/[R-3m], the [C2/m]/[R-3m] of the core differs from that of the shell in the secondary particle: [chemical formula 1] rLi.sub.2M1O.sub.3.Math.(1-r)Li.sub.aM2O.sub.2

The present invention provides the use of a lead (IV) containing compound to prepare a lead chalcogenide nanocrystal and a method for producing broadband lead chalcogenide nanocrystals in a low cost, size-controllable and scalable method, the method comprising contacting a lead (IV) containing compound with an organic acid and a chalcogen-containing reagent.