The present application discloses a positive electrode active material including a lithium nickel cobalt manganese oxide, the molar content of nickel in the lithium nickel cobalt manganese oxide accounts for 60%-90% of the total molar content of nickel, cobalt and manganese, and the lithium nickel cobalt manganese oxide has a layered crystal structure of a space group R 3m; a transition metal layer of the lithium nickel cobalt manganese oxide includes a doping element, and the local mass concentration of the doping element in particles of the positive electrode active material has a relative deviation of 20% or less; and in a differential scanning calorimetry spectrum of the positive electrode active material in a 78% delithiation state, an initial exothermic temperature of a main exothermic peak is 200° C. or more, and an integral area of the main exothermic peak is 100 J/g or less.

Provided are a ferrite powder capable of maintaining a high withstand voltage even when used in a resin composition having high magnetic properties and electrical resistivity and a high filling ratio, and a method for producing the same. A ferrite powder composed of spherical ferrite particles, wherein the ferrite powder contains iron (Fe): 55.0-70.0 mass % and manganese (Mn): 3.5-18.5 mass %, the ferrite powder containing more than 0.0 mass % to 7.5 mass % α-Fe.sub.2O.sub.3, and the ferrite powder has a volume average particle size (D50) of 15.0 μm or less.

A positive electrode active material powder for a lithium secondary battery, which includes a lithium composite transition metal oxide in the form of a single particle consisting of one nodule, or a pseudo-single crystal, which is a composite of 30 or less nodules, where the positive electrode active material powder satisfies Expression 1: 0.5≤D.sub.mean33 d.sub.press/D.sub.50≤3.Where D.sub.mean is an average particle diameter of the nodules as measured using an electron backscatter diffraction (EBSD) pattern analyzer, d.sub.press is a press density measured after 5 g of the positive electrode active material powder is input into a circular mold with a diameter of 2 cm and pressurized at a pressure of 2000 kgf, and D.sub.50 is a value corresponding to a cumulative volume of 50% in the particle size distribution of the positive electrode active material powder.

A composite artificial graphite includes a first graphite and a second graphite. The first graphite includes secondary particles and has a graphite interlayer spacing d.sub.002 of 0.33560 nm to 0.33610 nm. The second graphite includes primary particles and has a graphite interlayer spacing d.sub.002 of 0.33620 nm to 0.33670 nm. A mass percentage of the first graphite in the composite artificial graphite is 40% to 90%.

Composites of porous nano-featured silicon and various materials, such as carbon, are provided. The composites find utility in various applications, such as electrical energy storage electrodes and devices comprising the same.

Provided are graphene nanosheets having a polyaromatic hydrocarbon concentration of less than about 0.7% by weight and a tap density of less than about 0.08 g/cm.sup.3, as measured by ASTM B527-15 standard. The graphene nanosheets also have a specific surface area (B.E.T) greater than about 250 m.sup.2/g. Also provided are processes for producing graphene nanosheets as well as for removing polyaromatic hydrocarbons from graphene nanosheets, comprising heating said graphene nanosheets under oxidative atmosphere, at a temperature of at least about 200° C.

This application provides a silicon-based material, a preparation method thereof, and a secondary battery, a battery module, a battery pack, and an apparatus associated therewith. The silicon-based material includes a core structure and a coating layer provided on at least partial surface of the core structure, where the core structure includes both a silicon phase and a lithium metasilicate phase, and a particle size P of the lithium metasilicate phase is ≥30 nm. The silicon-based material of this application can not only increase energy density of a secondary battery with the silicon phase, but also improve structural stability and chemical stability of the silicon-based material, so that the secondary battery can deliver satisfactory and balanced cycling performance and first-cycle coulombic efficiency in overall.

According to the present invention, there are provided ferrite particles for bonded magnets and a resin composition for bonded magnets which are capable of producing a bonded magnet molded product having a good tensile elongation and exhibiting excellent magnetic properties, as well as a bonded magnet molded product such as a rotor which is obtained by using the resin composition. The present invention relates to ferrite particles for bonded magnets having a bulk density of not less than 0.5 g/cm.sup.3 and less than 0.6 g/cm.sup.3 and a degree of compaction of not less than 65%, a resin composition for bonded magnets using the ferrite particles, and a molded product obtained by using the ferrite particles and the resin composition.

A positive-electrode active material precursor for a nonaqueous electrolyte secondary battery is provided that includes a nickel-cobalt-manganese carbonate composite represented by general formula Ni.sub.xCo.sub.yMn.sub.zM.sub.tCO.sub.3 (where x+y+z+t=1, 0.05≤x≤0.3, 0.1≤y≤0.4, 0.55≤z≤0.8, 0≤t≤0.1, and M denotes at least one additional element selected from a group consisting of Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W) and a hydrogen-containing functional group, wherein H/Me representing the ratio of the amount of hydrogen to the amount of metal components Me included in the positive-electrode active material precursor is greater than or equal to 1.60.

A cobalt oxide for a lithium secondary battery, a method of preparing the cobalt oxide; a lithium cobalt oxide for a lithium secondary battery formed from the cobalt oxide; and a lithium secondary battery having a positive electrode including the lithium cobalt oxide, the cobalt oxide having a tap density of about 2.8 g/cc to about 3.0 g/cc, and an intensity ratio of about 0.8 to about 1.2 of a second peak at 2θ of about 31.3±1° to a first peak at 2θ of about 19±1° in X-ray diffraction spectra, as analyzed by X-ray diffraction.