A treatment process for crystallizing a metal sulfate involving pre-treating a feedstock comprising calcium, magnesium, and/or lithium impurities, the pre-treating involving pre-leaching the feedstock in the presence of a lixiviant, selectively extracting a first portion of any of the impurities from the feedstock, and forming a leached solution comprising an uncrystallized metal sulfate and any remaining impurities; and/or refining the leached solution and removing a second portion of any of the remaining impurities; and crystallizing the uncrystallized metal sulfate from the leached solution to form a crystallized metal sulfate. So processed, the crystallized metal sulfate may be battery-grade or electroplating-grade.

A method of producing ceria nanocrystals is provided. The method includes providing a gas that includes ozone to a solution that includes a cerium salt, and obtaining ceria nanocrystals from the solution after the gas is provided to the first solution. A method of producing nanoparticles is provided. The method includes providing a gas that includes ozone to a solution that includes a metal salt that includes at least one of a transition metal or a lanthanide, and producing at least one of metal oxide nanoparticles, metal oxynitrate nanoparticles, or metal oxyhydroxide nanoparticles from the solution after the gas is provided to the solution.

A method of producing ceria nanocrystals is provided. The method includes providing a gas that includes ozone to a solution that includes a cerium salt, and obtaining ceria nanocrystals from the solution after the gas is provided to the first solution. A method of producing nanoparticles is provided. The method includes providing a gas that includes ozone to a solution that includes a metal salt that includes at least one of a transition metal or a lanthanide, and producing at least one of metal oxide nanoparticles, metal oxynitrate nanoparticles, or metal oxyhydroxide nanoparticles from the solution after the gas is provided to the solution.

A method of making stable aqueous dispersions and concentrates of cobalt oxide nanoparticles is described, wherein a reaction mixture comprising cobalt(II) ion, a carboxylic acid, a base, an oxidant and water is formed, and in which cobalt oxide nanoparticles are formed. Cobalt oxide nanoparticles ranging in average crystallite size from about 4 nm to 15 nm are described. The cobalt oxide nanoparticles may be isolated and redispersed to form stable, homogeneous, aqueous dispersions of cobalt oxide nanoparticles containing from about 1 to about 20 weight percent cobalt oxide.

A method of making stable aqueous dispersions and concentrates of cobalt oxide nanoparticles is described, wherein a reaction mixture comprising cobalt(II) ion, a carboxylic acid, a base, an oxidant and water is formed, and in which cobalt oxide nanoparticles are formed. Cobalt oxide nanoparticles ranging in average crystallite size from about 4 nm to 15 nm are described. The cobalt oxide nanoparticles may be isolated and redispersed to form stable, homogeneous, aqueous dispersions of cobalt oxide nanoparticles containing from about 1 to about 20 weight percent cobalt oxide.

The present invention relates to the field of electrode material of a low temperature resistant supercapacitor, and in particular to a nickel foam-supported defective tricobalt tetroxide nanomaterial, a low temperature resistant supercapacitor and a preparation method thereof. The method includes the following steps: dissolving cobalt acetate in an ethylene glycol solution and stirring uniformly to obtain a pink transparent solution; adding hexadecyl trimethyl ammonium bromide to the pink transparent solution, and stirring until the hexadecyl trimethyl ammonium bromide dissolves to obtain a mixed solution; putting the mixed solution into a teflon-lined reactor, adding pretreated nickel foam for hydrothermal reaction, taking out the nickel foam after the reaction is completed, and ultrasonic cleaning the nickel foam repeatedly before drying; and heat-treating the nickel foam obtained after drying. The defective tricobalt tetroxide (D-Co.sub.3O.sub.4) grown on the nickel foam prepared by the present invention still has a high specific capacity at a low temperature, and the assembled supercapacitor can withstand low temperature, and thus has great application prospects.

The present invention relates to the field of electrode material of a low temperature resistant supercapacitor, and in particular to a nickel foam-supported defective tricobalt tetroxide nanomaterial, a low temperature resistant supercapacitor and a preparation method thereof. The method includes the following steps: dissolving cobalt acetate in an ethylene glycol solution and stirring uniformly to obtain a pink transparent solution; adding hexadecyl trimethyl ammonium bromide to the pink transparent solution, and stirring until the hexadecyl trimethyl ammonium bromide dissolves to obtain a mixed solution; putting the mixed solution into a teflon-lined reactor, adding pretreated nickel foam for hydrothermal reaction, taking out the nickel foam after the reaction is completed, and ultrasonic cleaning the nickel foam repeatedly before drying; and heat-treating the nickel foam obtained after drying. The defective tricobalt tetroxide (D-Co.sub.3O.sub.4) grown on the nickel foam prepared by the present invention still has a high specific capacity at a low temperature, and the assembled supercapacitor can withstand low temperature, and thus has great application prospects.

A metal double salt dispersion liquid including an organic solvent and a metal double salt, wherein the metal double salt has a composition represented by M(R.sup.1COO).sub.m-x-y(OH).sub.xA.sub.y(H.sub.2O).sub.z, where M is a metal element, R.sup.1 is a hydrogen atom or an alkyl group, A is an anion, m is a valence of the metal element M, 0<x+y<m, x>0, y≥0, and z≥0, and when the metal double salt dispersion liquid is subjected to a centrifugal operation at a relative centrifugal force of 10,000 G for 5 minutes, a proportion of metal elements not forming a precipitate to all metal elements contained in a total of the metal double salt dispersion liquid is 10.0 mol % or more.

Process for making a manganese composite (oxy)hydroxide with a mean particle diameter D50 in the range from 2 to 16 μm comprising the step(s) of combining (a) an aqueous solution containing salts of nickel and of manganese, and, optionally, at least one of Al, Mg, or transition metals other than nickel and manganese wherein at least 50 mole-% of the metal is manganese, (b) with an aqueous solution of an alkali metal hydroxide and (c) an organic acid or its alkali or ammonium salt wherein said organic acid bears at least two functional groups per molecule and at least one of the functional groups is a carboxylate group.

Process for making a manganese composite (oxy)hydroxide with a mean particle diameter D50 in the range from 2 to 16 μm comprising the step(s) of combining (a) an aqueous solution containing salts of nickel and of manganese, and, optionally, at least one of Al, Mg, or transition metals other than nickel and manganese wherein at least 50 mole-% of the metal is manganese, (b) with an aqueous solution of an alkali metal hydroxide and (c) an organic acid or its alkali or ammonium salt wherein said organic acid bears at least two functional groups per molecule and at least one of the functional groups is a carboxylate group.