A process for producing a silicon nitride powder characterized by comprising a step of providing a starting material powder containing not less than 90% by mass of a silicon powder; the step of filling a heat-resistant reaction vessel with the starting material powder; a step of obtaining a massive product thereof by a combustion synthesis reaction by igniting the starting material powder filled in the reaction vessel in a nitrogen atmosphere and permitting a heat of nitriding combustion of silicon to propagate to the whole starting material powder; and a step of mechanically milling the massive product by a dry method.

The positive electrode active material for a non-aqueous electrolyte secondary cell according to an embodiment of the present disclosure is characterized in having a Ni-containing lithium transition metal oxide having a layered structure; the proportion of Ni in the lithium transition metal oxide being 91 to 96 mol % relative to the total number of moles of metal elements excluding Li; a transition metal being present in the Li layer of the layered structure at an amount of 1 to 2.5 mol % relative to the total number of moles of transition metals in the Ni-containing lithium transition metal oxide; and the Ni-containing lithium transition metal oxide being such that the half width n of the diffraction peak for the (208) plane in an X-ray diffraction pattern obtained by X-ray diffraction is 0.3000.50.

To provide a sulfur-containing complex having few impurities, a method for producing the complex at a higher production efficiency, and a method for producing a solid electrolyte using the complex, a sulfur-containing complex, containing a lithium sulfide and a lithium halide, exhibiting, in X-ray diffractometry using a CuK ray, the diffraction angle of the peak of lithium halide shifting toward the diffraction angle of the peak of lithium sulfide, and not containing an oxygen-containing lithium halide represented by Li.sub.3OX (where X represents a halogen element) is provided. And a production method for a sulfur-containing complex including heating a solution containing a lithium hydrosulfide and a lithium halide in the presence of hydrogen sulfide is also provided.

There is provided a lithium-iron-manganese-based composite oxide capable of providing a lithium-ion secondary battery which has a high capacity retention rate in charge/discharge cycles and in which the generation of a gas caused by charge/discharge cycles is suppressed. A lithium-iron-manganese-based composite oxide having a layered rock-salt structure, wherein at least a part of the surface of a lithium-iron-manganese-based composite oxide represented by the following formula is coated with an oxide of at least one metal selected from the group consisting of La, Pr, Nd, Sm and Eu:
Li.sub.xM.sup.1.sub.(y-p)Mn.sub.pM.sup.2.sub.(z-q)Fe.sub.qO.sub.(2-) wherein 1.05x1.32, 0.33y0.63, 0.06z0.50, 0<p0.63, 0.06q0.50, 00.80, yp, and zq; M.sup.1 is at least one element selected from Ti and Zr; and M.sup.2 is at least one element selected from the group consisting of Co, Ni and Mn.

Provided are electrochemically active secondary particles that provide excellent capacity and improved cycle life. The particles are characterized by selectively enriched grain boundaries where the grain boundaries are enriched with Al and Co. The enrichment with Al reduces impedance generation during cycling thereby improving capacity and cycle life. Also provided are methods of forming electrochemically active materials, as well as electrodes and electrochemical cells employing the secondary particles.

A ruthenium oxide powder having a rutile crystal structure is provided, wherein a crystallite diameter D1, calculated from a peak of a (110) plane measured by an X-ray diffraction method, is 25 nm or more and 80 nm or less, a specific surface area diameter D2, calculated from a specific surface area, is 25 nm or more and 114 nm or less, and a ratio of the crystallite diameter D1 (nm) to the specific surface area diameter D2 (nm) satisfies a following formula (1).

0.70D1/D21.00 (1)

A ruthenium oxide powder having a rutile crystal structure is provided, wherein a crystallite diameter D1, calculated from a peak of a (110) plane measured by an X-ray diffraction method, is 25 nm or more and 80 nm or less, a specific surface area diameter D2, calculated from a specific surface area, is 25 nm or more and 114 nm or less, and a ratio of the crystallite diameter D1 (nm) to the specific surface area diameter D2 (nm) satisfies a following formula (1).
0.70D1/D21.00(1)

Nanostructured aluminosilicates including aluminosilicate nanorods are formed by heating a geopolymer resin containing up to about 90 mol % water in a closed container at a temperature between about 70 C. and about 200 C. for a length of time up to about one week to yield a first material including the aluminosilicate nanorods. The aluminosilicate nanorods have an average width of between about 5 nm and about 30 or between about 5 nm and about 60 nm or between about 5 nm and about 100 nm, and a majority of the aluminosilicate nanorods have an aspect ratio between about 2 and about 100.

A phosphorus-containing molecular sieve has a phosphorus content of about 0.3-5 wt %, a pore volume of about 0.2-0.95 ml/g, and a ratio of B acid content to L acid content of about 2-10. The molecular sieve has a specific combination of characteristics, including a high ratio of B acid content to L acid content, thereby exhibiting higher hydrocracking activity and ring-opening selectivity when used in the preparation of a hydrocracking catalyst.

A method of preparing cerium boride powder, according to the present invention, includes a first step for generating mixed powder by mixing at least one selected from among cerium chloride (CeCl.sub.3) powder and cerium oxide (CeO.sub.2) powder, at least one selected from among magnesium hydride (MgH.sub.2) powder and magnesium (Mg) powder, and boron oxide (B.sub.2O.sub.3) powder, a second step for generating composite powder including cerium boride (Ce.sub.xB.sub.y) and at least one selected from among magnesium oxide (MgO) and magnesium chloride (MgCl.sub.2), by causing reaction in the mixed powder at room temperature based on a ball milling process, and a third step for selectively depositing cerium boride powder by dispersing the composite powder in a solution.