A positive electrode active material precursor is provided, which includes a transition metal hydroxide particle represented by Formula 1 and a cobalt oxide particle and a manganese oxide particle attached to the surface of the transition metal hydroxide particle. A preparation method thereof, a positive electrode active material prepared using the same, a positive electrode including the positive electrode active material, and a secondary battery including the positive electrode are also provided.

The invention is directed towards an electrochemically active cathode material for a battery. The electrochemically active cathode material includes a non-stoichiometric beta-delithiated layered nickel oxide. The non-stoichiometric beta-delithiated layered nickel oxide has a chemical formula. The chemical formula is L.sub.ixA.sub.yNi.sub.1+a−zM.sub.zO.sub.2.Math.nH.sub.2O where x is from about 0.02 to about 0.20; y is from about 0.03 to about 0.20; a is from about 0.02 to about 0.2; z is from about 0 to about 0.2; and n is from about 0 to about 1. Within the chemical formula, A is an alkali metal. The alkali metal includes potassium, rubidium, cesium, and any combination thereof. Within the chemical formula, M comprises an alkaline earth metal, a transition metal, a non-transition metal, and any combination thereof.

The invention is directed towards an electrochemically active cathode material for a battery. The electrochemically active cathode material includes a non-stoichiometric beta-delithiated layered nickel oxide. The non-stoichiometric beta-delithiated layered nickel oxide has a chemical formula. The chemical formula is L.sub.ixA.sub.yNi.sub.1+a−zM.sub.zO.sub.2.Math.nH.sub.2O where x is from about 0.02 to about 0.20; y is from about 0.03 to about 0.20; a is from about 0.02 to about 0.2; z is from about 0 to about 0.2; and n is from about 0 to about 1. Within the chemical formula, A is an alkali metal. The alkali metal includes potassium, rubidium, cesium, and any combination thereof. Within the chemical formula, M comprises an alkaline earth metal, a transition metal, a non-transition metal, and any combination thereof.

A metal composite hydroxide represented by a general formula (1): Ni.sub.1−x−yCo.sub.xMn.sub.yM.sub.z(OH).sub.2+a, in which [(D90−D10)/MV] is 0.80 or more, the metal composite hydroxide contains a first particle having a core portion inside the particle and a shell portion formed around the core portion and a second particle having a uniform composition inside the particle, and the second particle has a similar composition to the shell portion and accounts for 60% or more of a total number of particles of 4 μm or less in the metal composite hydroxide.

A metal composite hydroxide represented by a general formula (1): Ni.sub.1−x−yCo.sub.xMn.sub.yM.sub.z(OH).sub.2+a, in which [(D90−D10)/MV] is 0.80 or more, the metal composite hydroxide contains a first particle having a core portion inside the particle and a shell portion formed around the core portion and a second particle having a uniform composition inside the particle, and the second particle has a similar composition to the shell portion and accounts for 60% or more of a total number of particles of 4 μm or less in the metal composite hydroxide.

The present invention provides a method of preparing a positive electrode active material precursor for a lithium secondary battery, a method of preparing a positive electrode active material for a lithium secondary battery in which the positive electrode active material precursor prepared by using the above method is used, and a positive electrode for a lithium secondary battery and a lithium secondary battery which include the positive electrode active material.

A composite material comprising NiMoO.sub.4—CoMoO.sub.4 nanosheets can be an electrode in a hybrid supercapacitor. A hybrid supercapacitor having a cathode comprising the composite material exhibits a large operating window, high energy density and high cycling stability. The heterostructure material may be formed by a one-step chemical bath deposition process.

A composite material comprising NiMoO.sub.4—CoMoO.sub.4 nanosheets can be an electrode in a hybrid supercapacitor. A hybrid supercapacitor having a cathode comprising the composite material exhibits a large operating window, high energy density and high cycling stability. The heterostructure material may be formed by a one-step chemical bath deposition process.

A nickel-hydrogen secondary battery includes an electrode group comprising a separator, a positive electrode, and a negative electrode, and the positive electrode contains a positive electrode active material including a base particle comprising a nickel hydroxide particle containing Mn in solid solution and a conductive layer comprising a Co compound and covering the surface of the base particle, wherein the X-ray absorption edge energy of Mn detected within 6500 to 6600 eV by measurement with an XAFS method is 6548 eV or higher.

A nickel-hydrogen secondary battery includes an electrode group comprising a separator, a positive electrode, and a negative electrode, and the positive electrode contains a positive electrode active material including a base particle comprising a nickel hydroxide particle containing Mn in solid solution and a conductive layer comprising a Co compound and covering the surface of the base particle, wherein the X-ray absorption edge energy of Mn detected within 6500 to 6600 eV by measurement with an XAFS method is 6548 eV or higher.