The disclosure relates to core-shell nanoparticle, the nanoparticle comprising a core being one or more selected from vaterite, proto-vaterite, and amorphous calcium carbonate as determined by X-Ray diffraction, remarkable in that the nanoparticle further comprises a shell of polyphenol, wherein said polyphenol is selected to be insoluble in water, to show a pH ranging from 5 to 9 when measured in a solution of one or more polar solvents and water at a concentration of 10 wt. % based on the total weight of said solution and wherein said polyphenol is at least partially soluble in said one or more polar solvents. A method for forming such nanoparticle as well as their use and the use of polyphenol as shell of shell-core nanoparticle is also described.

The present invention relates to silicon-compound-coated fine metal particles, with which surfaces of fine metal particles, composed of at least one type of metal element or metalloid element, are at least partially coated with a silicon compound and a ratio of SiOH bonds contained in the silicon-compound-coated fine metal particles is controlled to be 0.1% or more and 70% or less. By the present invention, silicon-compound-coated fine metal particles that are controlled in dispersibility and other properties can be provided by controlling the ratio of SiOH bonds or the ratio of SiOH bonds/SiO bonds contained in the silicon-compound-coated fine metal particles. By controlling the ratio of SiOH bonds or the ratio of SiOH bonds/SiO bonds, a composition that is more appropriate for diversifying applications and targeted properties of silicon-compound-coated fine metal particles than was conventionally possible can be designed easily.

A negative electrode active material for a lithium secondary battery, which includes a silicon-based particle represented by M-SiO.sub.x, wherein M is Li, Mg, Ca, Al, or Ti, and 0x<2, wherein the M-SiO.sub.x includes an amorphous phase at 20 wt % to 70 wt % based upon a total weight of the M-SiO.sub.x, thereby exhibiting excellent initial efficiency and lifespan characteristics, and a preparation method thereof.

A method for producing a silica sol containing a small amount of metal impurities and wherein colloidal silica having an elongated particle shape is dispersed in a solvent, by addition of a compound as an anion source and ammonia as an alkali source and heating of the resultant mixture at a predetermined temperature, includes the following steps: (a) preparing a raw material liquid by adding at least one compound as an anion source selected from the group of inorganic acids, organic acids, and ammonium salts of these acids, and ammonia to a silica sol as a raw material having SiO.sub.2 of 1% by mass to 30% by mass and a pH of 2 to 5 so the mass ratio of the compound to SiO.sub.2 is 0.5% to 1.9%; and (b) heating the raw material liquid prepared in step (a) at 80 C. to 200 C. for 0.5 hours to 20 hours.

The disclosure relates to porous Co.sub.3O.sub.4 nanoparticles which include flocculated amorphous primary nanoparticles, with air pores formed between the amorphous primary nanoparticles. The porous Co.sub.3O.sub.4 nanoparticles, according to an embodiment of the disclosure, may be in the form of flocculated amorphous primary nanoparticles of 1 nm or less, have a 400 times larger specific surface area than the conventional Co.sub.3O.sub.4 particles, and address the issue with the expansion of Co.sub.3O.sub.4 lattices which may arise when the battery is charged or discharged, thereby providing more reliability when applied to batteries.

A method of making a liquid dispersion for the manufacture of a photonic crystal. The method comprises dispersing monodispersed spheres in a liquid to form a liquid dispersion, and subjecting the liquid dispersion to an ultrasonic treatment. Ammonia solution may also be added to the liquid dispersion. The ultrasound treatment breaks up agglomerations of monodispersed spheres, and the resulting photonic crystal made using the dispersion is more highly ordered and hence of higher quality.

Disclosed herein are embodiments of doped and undoped spherical or spheroidal lithium lanthanum zirconium oxide (LLZO) powder products, and methods of production using microwave plasma processing, which can be incorporated into solid state lithium ion batteries. Advantageously, embodiments of the disclosed LLZO powder display a high quality, high purity stoichiometry, small particle size, narrow size distribution, spherical morphology, and customizable crystalline structure.

A porous and easy water soluble amorphous silica which does not contain tar, crystal, residual agrichemicals, and carcinogens, and method and apparatus to produce same, by using only one burning treatment from a plant including abundant silica, including a method of manufacturing the amorphous silica wherein rice family plants are burned while stirring and introducing into the furnace an atmospheric gas having a mass of 6.7 or more and 20 or less of the weight of the rice family plants, or oxygen gas having a weight of 1.4 or more and 4 or less with respect to the weight of the rice family plants, and at the same time as burning, combustion gas generated at the time of combustion is discharged.

A solid electrolyte material includes a first crystal phase. The first crystal phase has a composition that is deficient in Li as compared with a composition represented by the following composition formula (1).

Li.sub.3Y.sub.1Cl.sub.6formula (1)

A solid electrolyte material includes a first crystal phase. The first crystal phase has a composition that is deficient in Li as compared with a composition represented by the following composition formula (1).

Li.sub.3Y.sub.1Br.sub.6formula (1)