Provided is a new method for producing a positive electrode active material for lithium secondary batteries, by which even in the case of washing a spinel type lithium transition metal oxide with water or the like, the service life characteristics can be further enhanced, and the concentration of magnetic substances can be effectively reduced. Suggested is a method for producing a positive electrode active material for lithium secondary batteries, the method including a water washing step of bringing a powder of a spinel type lithium transition metal oxide into contact with a polar solvent and thereby washing the powder; and a drying step of subsequently drying the powder by heating the powder to 300 C. to 700 C. in an atmosphere containing oxygen.

Positive electrode active material particle powder includes: lithium manganese oxide particle powder having Li and Mn as main components and a cubic spinel structure with an Fd-3m space group. The lithium manganese oxide particle powder is composed of secondary particles, which are aggregates of primary particles, an average particle diameter (D50 ) of the secondary particles being from 4 m to 20 m, and at least 80% of the primary particles exposed on surfaces of the secondary particles each have a polyhedral shape having at least one (110) plane that is adjacent to two (111) planes.

Provided is an electrode material which leads to a lithium ion secondary battery that has high energy density. An electrode material for a lithium ion secondary battery of the present invention is characterized by containing: a coarse particle of a first active material that is able to act as a positive electrode active material or a negative electrode active material of a lithium ion secondary battery; and a particle of a composite composed of conductive carbon and a second active material attached to the conductive carbon that is able to act as an active material of the same electrode as the first active material. This electrode material for a lithium ion secondary battery is also characterized in that: a diameter of the coarse particle of the first active material is larger than a diameter of the particle of the composite; and the particle of the composite is filled in a gap formed between the particles of the first active material. A conductive agent can be additionally contained in the gap.

A compound M.sub.jX.sub.p which is particularly suitable for use in a battery prepared by the complexometric precursor formulation methodology wherein: M.sub.j is at least one positive ion selected from the group consisting of alkali metals, alkaline earth metals and transition metals and j is an integer representing the moles of said positive ion per moles of said M.sub.jX.sub.p; and X.sub.p, a negative anion or polyanion from Groups IIIA, IV A, VA, VIA and VIIA and may be one or more anion or polyanion and p is an integer representing the moles of said negative ion per moles of said M.sub.jX.sub.p.

The invention relates to a cathode active material for a high voltage secondary battery with a cathode arranged for being fully or mainly operated above 4.4 V vs. Li/Li.sup.+, wherein the cathode active material is an oxide that comprises sulfate as a capacity fade reducing compound. The invention also relates to a cathode active material for a high voltage secondary battery having the composition Li.sub.xM.sub.yMn.sub.2yO.sub.4v(SO.sub.4).sub.z, where 0.9x1.1, 0.4y0.5, 0<z0.1, 0vz and M is a transition metal chosen from the group consisting of Ni, Mg, Ti, V, Cr, Fe, Co, Cu, Zn, Al, Ga, Rb, Ge, Mo, Nb, Zr, Si and combinations thereof, wherein the cathode active material comprises sulfate as a capacity fade reducing compound.

Furthermore, the invention relates to a secondary battery comprising the cathode active material according to the invention, and to a method for preparing the cathode active materials of the invention.

The present invention relates to a cathode active material for a secondary battery and a preparation method thereof, and more particularly, to a lithium composite oxide including a secondary particle formed as primary particles cohere, in which a manganese (Mn) oxide is present in the periphery of the primary particles, a concentration of an Mn oxide in the primary particle has a concentration gradient from the center of the primary particle to a surface of the particle, a concentration of an Mn oxide in the secondary particle has a concentration gradient from a surface of the secondary particle to the center thereof, and a lithium ion migration path is formed in the primary particle, and a preparation method thereof. A secondary battery including the cathode active material for a secondary battery may have high safety, while exhibiting high capacity and high output.

A manufacturing method of a cathode active material for lithium secondary battery, including: preparing a first solution by mixing a metal oxide and a solvent; preparing a metal-mixed solution by adding an acidic solution to the first solution and then applying ultrasonic waves to the mixture; centrifuging the metal-mixed solution; preparing a second solution by mixing a supernatant of the centrifuged metal-mixed solution, a reductant, and a solvent and then applying ultrasonic waves to the mixture; obtaining powder by filtering and then drying the second solution; forming mesoporous spherical nanoparticles by mixing the powder, a metal, a lithium precursor, and a solvent, applying ultrasonic waves to the mixture and then drying the mixture; and performing a heat treatment to the spherical nanoparticles, and a cathode active material for a lithium secondary battery obtained by the manufacturing method. The cathode active material for lithium secondary battery is mesoporous spherical nanoparticles.

Provided is a method for recycling and refreshing a cathode material, a refreshed cathode material and a lithium ion battery. The method for recycling and refreshing the cathode material includes: 1) a cathode material recycled from a waste battery is mixed with a manganiferous salt solution; 2) an alkali aqueous solution is added to the mixture to react to obtain a manganese hydroxide coating cathode material; and 3) the manganese hydroxide coating cathode material is sintered with a lithium resource to obtain a refreshed cathode material. The refreshed cathode material has no obvious impurity phase and has good crystallinity, high initial charge-discharge efficiency and good cycling performance.

Provided are polycrystalline lithium manganese oxide particles represented by Chemical Formula 1 and a method of preparing the same:
Li.sub.(1+x)Mn.sub.(2xyf)Al.sub.yM.sub.fO.sub.(4z)<Chemical Formula 1> where M is any one selected from the group consisting of boron (B), cobalt (Co), vanadium (V), lanthanum (La), titanium (Ti), nickel (Ni), zirconium (Zr), yttrium (Y), and gallium (Ga), or two or more elements thereof, 0x0.2, 0<y0.2, 0<f0.2, and 0z0.2. According to an embodiment of the present invention, limitations, such as the Jahn-Teller distortion and the dissolution of Mn.sup.2+, may be addressed by structurally stabilizing the polycrystalline lithium manganese oxide particles. Thus, life characteristics and charge and discharge capacity characteristics of a secondary battery may be improved.

Provided is a material that can be used as a potassium secondary battery positive electrode active material (particularly a potassium ion secondary battery positive electrode active material), other than Prussian blue, by using a potassium compound and a potassium ion secondary battery positive electrode active material comprising the potassium compound, the potassium compound being represented by general formula (1):

K.sub.nA.sub.kBO.sub.m,

wherein A is a positive divalent element in groups 7 to 11 of the periodic table; B is positive tetravalent silicon, germanium, titanium or manganese, excluding a case in which A is manganese and B is titanium, and a case in which A is cobalt and B is silicon; n is 1.5 to 2.5; and m is 3.5 to 4.5.