Provided is a nickel-containing hydroxide coated with cobalt, having a coating layer containing cobalt oxyhydroxide formed on a nickel-containing hydroxide, in which an average circularity of particles having particle diameters equal to or more than a particle diameter at a cumulative volume percentage of 50% (D50) within a range of 0.900 or more and 0.990 or less.

Provided is a nickel-containing hydroxide which is a precursor of a positive electrode active material for a non-aqueous electrolyte secondary battery, wherein in the frequency distribution in the aspect ratio measurement of secondary particles of the nickel-containing hydroxide, the maximum peak value of the frequency is 4.60% or more.

Provided is a nickel-containing hydroxide which is a precursor of a positive electrode active material for a non-aqueous electrolyte secondary battery, wherein in the frequency distribution in the aspect ratio measurement of secondary particles of the nickel-containing hydroxide, the maximum peak value of the frequency is 4.60% or more.

A method of producing a composite hydroxide according to the present disclosure includes: by supplying an aqueous ammonia solution and sodium hydroxide to an aqueous solution including a compound containing nickel and a compound containing manganese, generating a nucleus while maintaining a pH at 12.0 to 13.5 on condition of a liquid temperature of 25 C. and an ammonium ion concentration at 5.3 to 11.7 g/L; and growing the nucleus while maintaining the pH at 9.7 to 10.8 on condition of the liquid temperature of 25 C. and the ammonium ion concentration at 20.0 to 26.4 g/L.

A method of producing a composite hydroxide according to the present disclosure includes: by supplying an aqueous ammonia solution and sodium hydroxide to an aqueous solution including a compound containing nickel and a compound containing manganese, generating a nucleus while maintaining a pH at 12.0 to 13.5 on condition of a liquid temperature of 25 C. and an ammonium ion concentration at 5.3 to 11.7 g/L; and growing the nucleus while maintaining the pH at 9.7 to 10.8 on condition of the liquid temperature of 25 C. and the ammonium ion concentration at 20.0 to 26.4 g/L.

Disclosed are positive electrode active materials for a rechargeable battery, positive electrodes including the positive electrode active materials, and rechargeable lithium batteries including the positive electrode active materials. The positive electrode active material comprises first particles comprising a compound having an olivine structure, second particles comprising a compound having a spinel structure, and third particles comprising a compound having a layered structure. The first particles and the second particles constitute a main active material, and the amount of the main active material is about 80 parts by weight to about 90 parts by weight based on 100 parts by weight of the positive electrode active material.

Disclosed are positive electrode active materials for a rechargeable lithium battery and positive electrodes including the positive electrode active materials. The positive electrode active material comprises first particles comprising a compound having an olivine structure, second particles having a spinel structure, and third particles having a layered structure. The amount of the third particles is about 10 parts by weight to about 50 parts by weight based on 100 parts by weight of the positive electrode active material.

Disclosed are positive electrode active materials for a rechargeable lithium battery and positive electrodes including the positive electrode active materials. The positive electrode active material comprises first particles comprising a compound having an olivine structure, second particles having a spinel structure, and third particles having a layered structure. The amount of the third particles is about 10 parts by weight to about 50 parts by weight based on 100 parts by weight of the positive electrode active material.

The present application relates to a positive electrode active materials for a rechargeable lithium battery, positive electrodes including the same, and rechargeable lithium batteries including the same. For example, the positive electrode active material includes first particles including a compound of Chemical Formula 1 and having a first average particle diameter, and second particles including a compound of Chemical Formula 2 and having a second average particle diameter that is greater than the first average particle diameter. The content of the first particles is greater than the content of the second particles.

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A catalyst and anode for hydrogen production by electrolysis as well as a preparation method, activation method and use thereof are provided. The anode for hydrogen production by electrolysis includes a catalyst which is nickel iron barium hydrotalcite with a nano hexagonal sheet structure and a thickness of 100-200 nm. The catalyst can be prepared by a one-step solvothermal reaction method. Alkaline-earth metal ions are evenly doped in the nickel iron barium hydrotalcite and are in atomic level dispersion, so that the anode for hydrogen production by electrolysis based on the catalyst, when being applied to a process for hydrogen production by electrolysis of an aqueous solution containing chlorine ions, not only can maintain good catalytic performance, but also has greatly improved chlorine ion corrosion resistance, leading to significant improvement of working stability and service life.