A precursor for sodium-ion battery positive electrode material and a preparation method therefor, a sodium-ion battery positive electrode material, a sodium-ion battery, and an electrical device are provided. The precursor for sodium-ion battery positive electrode material has a chemical general formula of Ni.sub.xMn.sub.yFe.sub.1-x-y(OH).sub.2, wherein 0.15x0.35, and 0.2y0.5. The precursor for sodium-ion battery positive electrode material contains a S element with a content of 4000 ppm, and has a Na/S mass ratio of 1.5.

Disclosed herein is a process for making an (oxy)hydroxide of TM where TM refers to metals of which at least 97 mol-% are transition metals and where TM includes manganese and nickel, and where at least 50 mol-% of TM are manganese, the process including the steps of: (a) providing at least one aqueous solution () of water-soluble salts of such metals and an aqueous solution () including alkali metal hydroxide selected from the group consisting of NaOH and KOH, (b) combining solutions () and () at a pH value in the range of from 9.5 to 10.3, where such step (b) is carried out using at least one coaxial mixer including two coaxially orientated pipes through which an aqueous solution () and an aqueous solution of () are introduced into a stirred vessel, thereby precipitating an (oxy)hydroxide of TM, and (c) recovering and drying the (oxy)hydroxide of TM.

Disclosed herein is a process for making an (oxy)hydroxide of TM where TM refers to metals of which at least 97 mol-% are transition metals and where TM includes manganese and nickel, and where at least 50 mol-% of TM are manganese, the process including the steps of: (a) providing at least one aqueous solution () of water-soluble salts of such metals and an aqueous solution () including alkali metal hydroxide selected from the group consisting of NaOH and KOH, (b) combining solutions () and () at a pH value in the range of from 9.5 to 10.3, where such step (b) is carried out using at least one coaxial mixer including two coaxially orientated pipes through which an aqueous solution () and an aqueous solution of () are introduced into a stirred vessel, thereby precipitating an (oxy)hydroxide of TM, and (c) recovering and drying the (oxy)hydroxide of TM.

A method for preparing a positive electrode active material, a precursor of a positive electrode active material including a lithium nickel-manganese-based composite oxide, the method including: preparing a nickel-manganese-based oxide precursor by subjecting a nickel-manganese-based hydroxide, having a manganese content of about 34 mol % to about 50 mol % based on 100 mol % of a total metal, to a first heat-treatment at a temperature of less than or equal to about 500 C.; mixing the nickel-manganese-based oxide precursor and a lithium raw material to form a mixture at a molar ratio of lithium of the lithium raw material to the total metal of the nickel-manganese-based oxide precursor being greater than about 1 and less thans or equal to about 2; and subjecting the mixture to a second heat-treatment.

A method for preparing a positive electrode active material, a precursor of a positive electrode active material including a lithium nickel-manganese-based composite oxide, the method including: preparing a nickel-manganese-based oxide precursor by subjecting a nickel-manganese-based hydroxide, having a manganese content of about 34 mol % to about 50 mol % based on 100 mol % of a total metal, to a first heat-treatment at a temperature of less than or equal to about 500 C.; mixing the nickel-manganese-based oxide precursor and a lithium raw material to form a mixture at a molar ratio of lithium of the lithium raw material to the total metal of the nickel-manganese-based oxide precursor being greater than about 1 and less thans or equal to about 2; and subjecting the mixture to a second heat-treatment.

Provided is a nickel-containing hydroxide as a precursor of a cathode active material for a non-aqueous electrolyte secondary battery, wherein the nickel-containing hydroxide is secondary particles formed by agglomeration of a plurality of primary particles, and the primary particles have an average area of 0.035 m.sup.2 or more.

Provided is a nickel-containing hydroxide as a precursor of a cathode active material for a non-aqueous electrolyte secondary battery, wherein the nickel-containing hydroxide is secondary particles formed by agglomeration of a plurality of primary particles, and the primary particles have an average area of 0.035 m.sup.2 or more.

Provided is a metal composite compound, wherein a relative standard deviation of a volume-based crystallite size distribution, calculated from a diffraction peak within the range 2=381 in a powder X-ray diffraction measurement using CuK radiation, is less than 0.70.

Provided is a metal composite compound, wherein a relative standard deviation of a volume-based crystallite size distribution, calculated from a diffraction peak within the range 2=381 in a powder X-ray diffraction measurement using CuK radiation, is less than 0.70.

A method provides for separating nickel from an aqueous solution using an organicaqueous extraction by performing one or more liquid-liquid extraction stages performed using an input aqueous solution comprising lithium ions, nickel ions, and cobalt ions and/or manganese ions, wherein each extraction stage comprises mixing an aqueous phase with dissolved metal sulfate with an organic solvent having dissolved di-(2,4,4-trimethylpentyl) phosphinic acid from 30% to 70% hydroxyl saponified with alkali, NH.sub.4.sup.+ or nickel counter ions. A collected purified aqueous phase comprising at least 90% of the nickel from the input aqueous solution and no more than about 5% of the each of the cobalt and manganese. The input aqueous solution is prepared from recovered lithium ion battery material.