The present invention relates to cerium-based particles and their use as a component of a composition for polishing. The present invention also relates to the method of preparation of the cerium-based particles.

A nickel-based active material for a lithium secondary battery, a method of preparing the nickel-based active material, and a lithium secondary battery including a positive electrode including the nickel-based active material, the nickel-based active material comprising a secondary particle having an outer portion with a radially arranged structure and an inner portion with an irregular porous structure, wherein the inner portion of the secondary particle has a larger pore size than the outer portion of the secondary particle.

A core-shell quantum dot including a core including a first semiconductor nanocrystal, the first semiconductor nanocrystal including zinc, tellurium, and selenium and a semiconductor nanocrystal shell disposed on the core, the semiconductor nanocrystal shell including zinc and selenium, sulfur, or a combination thereof and a production thereof are disclosed, wherein the core-shell quantum dot does not include cadmium, lead, mercury, or a combination thereof, wherein the core-shell quantum dot(s) includes chlorine, wherein in the core-shell quantum dot, a mole ratio of chlorine with respect to tellurium is greater than or equal to about 0.01:1 and wherein a quantum efficiency of the core-shell quantum dot is greater than or equal to about 10%.

This application discloses a negative-electrode active material and a preparation method thereof, a secondary battery, and a battery module, a battery pack, and an apparatus that include such secondary battery. The negative-electrode active material includes a core and a coating layer covering at least part of a surface of the core, where the core includes artificial graphite, the coating layer includes amorphous carbon, a volume-based particle size distribution of the negative-electrode active material satisfies D.sub.v99≤24 μm, a volume-based median particle size D.sub.v50 of the negative-electrode active material satisfies 8 μm≤D.sub.v≤15 μm, D.sub.v99 is a particle size corresponding to a cumulative volume distribution percentage of the negative-electrode active material reaching 99%, and WO is a particle size corresponding to a cumulative volume distribution percentage of the negative-electrode active material reaching 50%.

The present invention provides a composite oxide that can achieve a high low-temperature output characteristic, a method for manufacturing the same, and a positive electrode active material in which the generation of soluble lithium is suppressed and a problem of gelation is not caused during the paste preparation. A positive electrode active material for non-aqueous electrolyte secondary batteries, including a lithium-metal composite oxide powder including a secondary particle configured by aggregating primary particles containing lithium, nickel, manganese, and cobalt, or a lithium-metal composite oxide powder including both the primary particles and the secondary particle. The secondary particle has a porous structure inside as a main inside structure, the slurry pH is 11.5 or less, the soluble lithium content rate is 0.5 [% by mass] or less, the specific surface area is 3.0 to 4.0 [m.sup.2/g], and the porosity is more than 50 to 80 [%].

A negative electrode material includes silicon-based particles and graphite particles. In a case that a D.sub.n50/D.sub.v50 ratio of the graphite particles is A and a D.sub.n50/D.sub.v50 ratio of the silicon-based particles is B, the following conditional expressions (1) to (3) are satisfied: 0.1≤A≤0.65 (1); 0.3≤B≤0.85 (2); and B>A (3), where, D.sub.v50 is a particle diameter of particles measured when a cumulative volume fraction in a volume-based distribution reaches 50%, and D.sub.n50 is a particle diameter of particles measured when a cumulative number fraction in a number-based distribution reaches 50%. The present invention further provides a negative electrode plate, a lithium-ion secondary battery or electrochemical device containing the negative electrode plate, and an electronic device containing the lithium-ion secondary battery and/or electrochemical device.

Provided are a method of preparing a metal oxide-silica composite aerogel, and a metal oxide-silica composite aerogel having an excellent weight reduction property prepared by the method. The method includes a step of adding an acid catalyst to a first water glass solution to prepare an acidic water glass solution (step 1); a step of adding a metal ion solution to the acidic water glass solution to prepare a precursor solution (step 2); and a step of adding a second water glass solution to the precursor solution and performing a gelation reaction (step 3) to yield a metal oxide-silica composite wet gel, wherein, in steps 2 and 3, bubbling of an inert gas is performed during the adding of the metal ion solution or the second water glass solution, respectively.

The present invention provides a composite oxide that can achieve a high low-temperature output characteristic, a method for manufacturing the same, and a positive electrode active material in which the generation of soluble lithium is suppressed and a problem of gelation is not caused during the paste preparation. A positive electrode active material for non-aqueous electrolyte secondary batteries, including a lithium-metal composite oxide powder including a secondary particle configured by aggregating primary particles containing lithium, nickel, manganese, and cobalt, or a lithium-metal composite oxide powder including both the primary particles and the secondary particle. The secondary particle has a porous structure inside as a main inside structure, the slurry pH is 11.5 or less, the soluble lithium content rate is 0.5[% by mass] or less, the specific surface area is 3.0 to 4.0 [m.sup.2/g], and the porosity is more than 50 to 80[%].

A nanostructure is provided that in one embodiment includes a cluster of cylindrical bodies. Each of the cylindrical bodies in the cluster are substantially aligned with one another so that their lengths are substantially parallel. The composition of the cylindrical bodies include tungsten (W) and sulfur (S), and each of the cylindrical bodies has a geometry with at least one dimension that is in the nanoscale. Each cluster of cylindrical bodies may have a width dimension ranging from 0.2 microns to 5.0 microns, and a length greater than 5.0 microns. In some embodiments, the cylindrical bodies are composed of tungsten disulfide (WS.sub.2). In another embodiment the nanolog is a particle comprised of external concentric disulfide layers which encloses internal disulfide folds and regions of oxide. Proportions between disulfide and oxide can be tailored by thermal treatment and/or extent of initial synthesis reaction.

A cubic boron nitride particle population having highly-etched surfaces and a high toughness index is produced by blending a reactive metal powder with a plurality of cubic boron nitride particles to form a blended mixture. The blended mixture is compressed to form a compressed mixture. The compressed mixture is subjected to a temperature and a pressure, where the temperature is controlled to cause etching of the plurality of cubic boron nitride particles by reaction of cubic boron nitride with the reactive metal powder, thereby forming a plurality of etched cubic boron nitride particles. Also, the temperature and pressure are controlled to cause boron nitride to remain in a cubic boron nitride phase. Afterwards, the plurality of etched cubic boron nitride particles is recovered from the compressed mixture to form the particle population. Preferably, the particle population contains no hexagonal boron nitride.