A positive electrode active material is constituted by lithium transition metal-containing composite oxide particles having a layered rock salt type crystal structure and are composed of secondary particles each formed of an aggregation of primary particles. The secondary particles have a d50 of 3.0 to 7.0 μm, a BET specific surface area of 1.8 to 5.5 m.sup.2/g, a pore peak diameter of 0.01 to 0.30 μm, and a log differential pore volume [dV/d(log D)] of 0.2 to 0.6 ml/g within a range of the pore peak diameter. In each of a plurality of primary particles having a primary particle size of 0.1 to 1.0 μm, a coefficient of variation of the concentration of an additive element M is 1.5 or less.

A positive active material includes a nickel-based composite metal oxide having the form of secondary particles in which a plurality of primary particles are agglomerated, where each secondary particle includes a core and a shell, the primary particles of the shell are coated with a manganese-containing nickel-based composite metal oxide, and the manganese-containing nickel-based composite metal oxide has a layered structure.

According to an embodiment, there is provided an electrode including an active material-containing layer. A logarithmic differential pore volume distribution curve of the active material-containing layer by a mercury intrusion method includes first and second peaks. The first peak is a local maximum value in a range where a pore size is from 0.1 μm or more to 0.5 μm or less. The second peak is a local maximum value in a range where the pore size is from 0.5 μm or more to 1.0 μm or less. An intensity A1 of the first peak and an intensity A2 of the second peak satisfy 0.1≤A2/A1≤0.3. A density of the active material-containing layer is from 2.9 g/cm.sup.3 or more to 3.3 g/cm.sup.3 or less.

Disclosed herein is a polymeric film, the film comprising a polymeric matrix material, a plurality of perovskite nanocrystals and/or aggregates of perovskite nanocrystals dispersed throughout the polymeric matrix material. There is also disclosed a perovskite polymer resin composition, a perovskite-polymer resin composition, a perovskite ink and a method of forming a luminescent film using any one of the compositions or ink. Preferably, the perovskite material is a lead halide perovskite containing a cation selected from Cs, an alkylammonium ion, or a formamidinium ion. The polymeric matrix is preferably formed from monomers comprising a vinyl or an acrylate group.

A water-based graphene dispersion is made by shear stabilization. The method of preparing the water-based graphene dispersion using shear stabilization includes adding a composition containing a graphene powder, a super wetter surfactant and a water dispersible rheology agent into water to form an aqueous mixture; and shearing the aqueous mixture under high pressures to break down the thick layers of the graphene powder to thin layers of graphene platelet particles and to form the water-based graphene dispersion with the graphene platelet particles dispersed in the water-based graphene dispersion. The water-based graphene dispersion is stable without visible phase separation after storage at room temperature for at least one year or even more than one year.

The present invention pertains to a process for preparing particles of rare earth sulfide comprising the steps of:—preparing a reaction mixture comprising at least one compound comprising at least one rare earth element (A) and at least one alkali metal sulfide (B),—submitting said reaction mixture to a mechanical stress so as to cause a chemical reaction that produces the particles of rare earth sulfide.

Cathode active material in particulate form with a mean particle diameter in the range from 2 to 16 .Math.m (D50), wherein the cathode active material has the composition Li.sub.1+xTM.sub.1-xO.sub.2 wherein x is in the range of from 0.1 to 0.2 and TM is a combination of elements according to general formula (I), (Ni.sub.aCo.sub.bMn.sub.c).sub.1-d-eM.sup.1.sub.dM.sup.2.sub.e where the variables are each defined as follows: a is in the range from 0.20 to 0.40, b is in the range of from zero to 0.15, c is in the range of from 0.50 to 0.75, d is in the range of from zero to 0.015, and e is in the range of from zero to 0.02, M.sup.1 is selected from Al, Ti, Zr, Mo, W, Fe, Nb, and Mg, M.sup.2 is selected from B and K, with a + b + c = 1.0 wherein said composite oxide has a specific surface (BET) in the range from 0.5 m.sup.2/gto 10 m.sup.2/gand a pressed density of at least 2.9 g/cm.sup.3, and wherein said cathode active material has an average primary particle diameter in the range of from 200 to 3,000 nm.

The present invention relates to an abrasive and a planarization method using the same, and more particularly, includes fumed silica. A BET specific surface area of the fumed silica is 200 m.sup.2/g to 450 m.sup.2/g, a shape of aggregates dispersed in the abrasive has an elongated shape or a round shape, and a ratio of the round shape of the aggregates is 50% to 90%.

A positive electrode active material includes lithium transition metal-containing composite oxide particles containing an additive element M1 and includes a coating layer formed of a metal composite oxide of Li and a metal element M2 on a part of a surface of the particles. The particles have a d50 of 3.0 to 7.0 μm, a BET specific surface area of 2.0 to 5.0 m.sup.2/g, a tap density of 1.0 to 2.0 g/cm.sup.3, and an oil absorption amount of 30 to 60 ml/100 g. For each of a plurality of primary particles having a primary particle size within a range of 0.1 to 1.0 μm among the primary particles, a coefficient of variation of the concentration of M1 is 1.5 or less, and the amount of M2 is 0.1 to 1.5 atom % with respect to the total number of atoms of Ni, Mn, and Co contained in the composite oxide particles.

Powder comprising particles comprising a matrix material and silicon-based domains dispersed in this matrix material, whereby the matrix material is carbon or a material that can be thermally decomposed to carbon, whereby either part of the silicon-based domains are present in the form of agglomerates of silicon-based domains whereby at least 98% of these agglomerates have a maximum size of 3 μm or less, or the silicon-based domains are not at all agglomerated into agglomerates.