A process for recovering carbonized lignin having a defined grain size distribution from a lignin-containing liquid is provided. The lignin-containing liquid is subjected to a hydrothermal carbonization to convert the lignin into a carbonized lignin and the carbonized lignin is separated from the liquid containing the carbonized lignin. The lignin-containing liquid is subjected to a hydrothermal carbonization at temperatures in the range from about 150° C. to about 280° C. and by adapting the H+ ion concentration in the lignin-containing liquid before and/or during the hydrothermal carbonization the grain size distribution of the carbonized lignin is adjusted.

A positive electrode active material for a nonaqueous electrolyte secondary battery is used for a nonaqueous electrolyte secondary battery. The positive electrode active material includes a composite oxide containing at least lithium, nickel, and manganese and contains aggregated particles of primary particles having an average particle diameter of 1.0 μm or more. The primary particles have a layered crystal structure and a spinel crystal structure.

Bandgap-tunable perovskite compositions are provided having the formula CsPb(A.sub.xB.sub.y).sub.3, wherein A and B are each a halogen. The mixed halide perovskite composition has a morphology which suppresses phase segregation to stabilize a tuned bandgap of the mixed halide perovskite composition. For example, the perovskite may be in the form of nanocrystals embedded in a non-perovskite matrix, which, for example, may have the formula Cs.sub.4Pb(A.sub.xB.sub.y).sub.6, wherein A and B are each a halogen. Solar cells and light-emitting diodes comprising the mixed perovskite compositions are also provided.

Provided is an alumina-based composite oxide having a large initial specific surface area and a small initial mean pore size, with excellent heat resistance of the specific surface area and pore volume; and a production method therefor. Specifically, provided is an alumina-based composite oxide wherein the initial crystallite diameter is 10 nm or less and the initial specific surface area is 80 m.sup.2/ml or more; after calcination at 1200° C. for 3 hours in air, the specific surface area is 10 m.sup.2/ml or more; the initial mean pore size is 10 nm or more and 50 nm or less; and after calcination at 1200° C. for 3 hours in air, the pore volume retention rate is 10% or more, which is determined by (P.sub.1/P.sub.0)×100 wherein P.sub.0 represents an initial pore volume (ml/g), and P.sub.1 represents a pore volume (ml/g) after calcination at 1200° C. for 3 hours in air.

A negative electrode active material comprising: particles of negative electrode active material, wherein the particles of negative electrode active material contain particles of silicon compound containing a silicon compound (SiO.sub.x:0.5≤x≤1.6), and wherein the particles of silicon compound have, as chemical shift values obtained from a .sup.29Si-MAS-NMR spectrum, an intensity A of a peak derived from amorphous silicon obtained in −40 to −60 ppm, an intensity B of a peak derived from silicon dioxide obtained in the vicinity of −110 ppm, and an intensity C of a peak derived from Si obtained in the vicinity of −83 ppm, which satisfy the following formula 1 and formula 2.
B≤1.5×A  (1)
B<C  (2)

A rapid synthesis method of a small-crystal-grain ZSM-5 molecular sieve, the method comprising: preparing a mixed silicon-aluminum glue solution, placing the solution in a crystallization kettle for low-temperature nucleation, enabling high-temperature crystallization growth of the solution, and obtaining a crystallization product, namely, a small-crystal-grain ZSM-5 molecular sieve, the nucleation temperature being 60-120° C., nucleation time being 1-3 hours, a crystallization growth temperature being 150-170° C., and crystallization growth time being 1-3 hours. The method is easy to operate, and has a short operation time, thus being able to complete within 6 hours; in addition, the product has uniform grain sizes, is in a mono-dispersed state, and has a high crystallization degree to a submicron degree.

A positive electrode active material, which has a crystallite size α/crystallite size β ratio (α/β) of 1 to 1.75 or less, wherein the crystallite size α is within a peak region of 2θ=18.7±1° and the crystallite size β is within a peak region of 2θ=44.6±1°, each determined by a powder X-ray diffraction measurement using Cu-Kα ray, and has a composition represented by formula (I) below:

Li[Li.sub.x(Ni.sub.aCo.sub.bMn.sub.cM.sub.d).sub.1-x]O.sub.2  (I)

wherein 0≦x≦0.2, 0.3<a<0.7, 0<b<0.4, 0<c<0.4, 0≦d<0.1, a+b+c+d=1, and M is at least one metal selected from the group consisting of Fe, Cr, Ti, Mg, Al and Zr.

A poly-crystalline silicon ingot having a bottom and defining a vertical direction includes a plurality of silicon grains grown in the vertical direction, in which the plurality of the silicon grains have at least three crystal orientations; and a nucleation promotion layer comprising a plurality of chips and chunks of poly-crystalline silicon on the bottom, wherein the poly-crystalline silicon ingot has a defect density at a height ranging from about 150 mm to about 250 mm of the poly-crystalline silicon ingot that is less than 15%.

A lithium composite transition metal oxide includes nickel (Ni), cobalt (Co), and manganese (Mn), wherein the lithium composite transition metal oxide includes two or more kinds of first dopants selected from the group consisting of Zr, Al, V, Co, and Mg and two or more kinds of second dopants selected from the group consisting of Ti, Y, Sr, Nb, Ba, and Ca, and particles of the lithium composite transition metal oxide has a crystallite size of 170-300 nm.

A method of producing a boron nitride polycrystal includes: a first step of obtaining a thermally treated powder by thermally treating a powder of a high pressure phase boron nitride at more than or equal to 1300° C.; and a second step of obtaining a boron nitride polycrystal by sintering the thermally treated powder under a condition of 8 to 20 GPa and 1200 to 2300° C.