A method of making Co.sub.3O.sub.4 nanorods by thermal decomposition of a cobalt salt is described. A method of using Co.sub.3O.sub.4 nanorods as an electrocatalyst component to a porous carbon electrode is also described. The carbon electrode may be made of carbonized filter paper. Together, this carbon-supported Co.sub.3O.sub.4 electrode may be used for water electrolysis.

A method of making Co.sub.3O.sub.4 nanorods by thermal decomposition of a cobalt salt is described. A method of using Co.sub.3O.sub.4 nanorods as an electrocatalyst component to a porous carbon electrode is also described. The carbon electrode may be made of carbonized filter paper. Together, this carbon-supported Co.sub.3O.sub.4 electrode may be used for water electrolysis.

The invention relates to a method for producing a metal chalcogenide thin film electrode, comprising the steps: (a) contacting a metal or metal oxide with an elementary halogen in a non-aqueous solvent, producing a metal halide compound in the solution, (b) applying a negative electric voltage to an electrically conducting or semiconducting substrate which is in contact with the solution from step (a), and (c) during and/or after step (b) contacting the substrate with an elementary chalcogen forming a metal chalcogenide layer on the substrate. The invention also relates to a metal chalcogenide thin film electrode which can be produced by the method and its use as an anode for releasing oxygen during (photo)electrochemical water splitting.

The invention relates to a method for producing a metal chalcogenide thin film electrode, comprising the steps: (a) contacting a metal or metal oxide with an elementary halogen in a non-aqueous solvent, producing a metal halide compound in the solution, (b) applying a negative electric voltage to an electrically conducting or semiconducting substrate which is in contact with the solution from step (a), and (c) during and/or after step (b) contacting the substrate with an elementary chalcogen forming a metal chalcogenide layer on the substrate. The invention also relates to a metal chalcogenide thin film electrode which can be produced by the method and its use as an anode for releasing oxygen during (photo)electrochemical water splitting.

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.

Process for precipitating a carbonate or (oxy)hydroxide comprising nickel from an aqueous solution of a nickel salt wherein such process is carried out in a vessel comprising (A) a vessel body, (B) one or more elements that control the hydraulic flow of the slurry formed during the precipitation and that induce a loop-type circulation flow, and (C) a stirrer whose stirrer element is in the vessel but located separately from the element(s) (B).

Process for precipitating a carbonate or (oxy)hydroxide comprising nickel from an aqueous solution of a nickel salt wherein such process is carried out in a vessel comprising (A) a vessel body, (B) one or more elements that control the hydraulic flow of the slurry formed during the precipitation and that induce a loop-type circulation flow, and (C) a stirrer whose stirrer element is in the vessel but located separately from the element(s) (B).

The present application relates to a metal oxide and synthesis of a lithium ion battery. Specifically, the present application selects a cobalt oxide compound, which uses Co.sub.3O.sub.4 as a main body, as a precursor of lithium cobalt oxide, and anion doping is performed in particles of Co.sub.3O.sub.4 to obtain a doped precursor for lithium cobalt oxide. The general formula of the precursor can be expressed as Co.sub.3(O.sub.1-yM.sub.y).sub.4, where about 0<y<about 0.2, and wherein the anion M comprises at least one of F, P, S, Cl, N, As, Se, Br, Te, I or At. The lithium ion battery with a cathode made of lithium cobalt oxide material prepared by using the precursor presents good cycle stability in a high voltage charge-discharge environment.

A layered double hydroxide is represented by the following formula (I): Ni.sup.2+.sub.1?(x+y+z)Fe.sup.3+.sub.xV.sup.3+.sub.yCo.sup.3+.sub.z(OH).sub.2A.sup.n?.sub.(x+y+z)/n.Math.mH.sub.2O . . . (I). In one embodiment, in the formula (I), (x+y+z) is from 0.2 to 0.5, x represents more than 0 and 0.3 or less, y represents from 0.04 to 0.49, and z represents more than 0 and 0.2 or less.