A potassium hexafluoromanganate is represented by General Formula: K.sub.2MnF.sub.6, and a diffuse reflectance with respect to light having a wavelength of 550 nm is 60% or more.

The present disclosure provides HRG-Mn.sub.3O.sub.4 hybrid nanoparticles. The HRG-Mn.sub.3O.sub.4 hybrid nanoparticles do not pose any cytotoxicity at normal physiological conditions and therefore they are nontoxic and biocompatible at physiological conditions. The HRG-Mn.sub.3O.sub.4 hybrid nanoparticles under exposure of laser light cause massive cellular damage indicating their potential use for photodynamic therapy of cancer. The HRG-Mn.sub.3O.sub.4 hybrid nanoparticles enhance the magnetic resonance signals from cancer cells and exhibit excellent MRI contrast property for tumor imaging and are therefore useful contrast agent.

A positive-electrode active material containing a compound that has a crystal structure belonging to the space group FM-3M and is represented by the composition formula (1):
Li.sub.xMe.sub.yO.sub.αF.sub.β  (1) wherein Me denotes one or two or more elements selected from the group consisting of Mn, Co, Ni, Fe, and Al, and the following conditions are satisfied. 1.3≤x≤2.2, 0.8≤y≤1.3, 1≤α≤2.93, 0.07≤β≤2.

A method according to an embodiment is for recovering a valuable metal from a waste electrode material of a lithium secondary battery by using lithium carbonate. An anode-cathode mixed electrode material that has been separated by draining, crushing, screening, and sorting a waste lithium secondary battery is preprocessed. A precipitation operation performed by adding lithium carbonate (Li2CO3) to a metal melt acquired by performing sulfuric acid dissolution using sulfuric acid. A valuable metal such as nickel, cobalt, manganese, aluminum, and copper is recovered as a residue in the form of a carbonate composite, and a lithium sulfate (Li2SO4) aqueous solution including lithium is recovered as a filtrate.

Provided are an olivine-type positive electrode active material for a lithium secondary battery, a method for preparing the same, and a lithium secondary battery comprising the same, wherein the olivine-type positive electrode active material may be represented by Formula 1:

Li.sub.wMn.sub.1-(x+y+z)M.sub.xM′.sub.yM.sup.41.sub.zPO.sub.4   Formula [1]

wherein, in Formula 1,

0.95<w≦1.05,

0<x≦0.1,

0<y≦5 0.1,

0<z≦0.1,

provided that 0<x+y+z≦0.2, and M, M′, and M″ are each independently an element selected from the group consisting of Ni, Co, Fe, Mg, V, Zn, Cu, Al, and Ga.

A method for producing a mixed metal solution containing manganese ions and at least one of cobalt ions and nickel ions, the method including: an Al removal step of subjecting an acidic solution containing at least manganese ions and aluminum ions, and at least one of cobalt ions and nickel ions, to removal of the aluminum ions by extracting the aluminum ions into a solvent while leaving at least a part of the manganese ions in the acidic solution in an aqueous phase, the acidic solution being obtained by subjecting battery powder of lithium ion batteries to a leaching step; and a metal extraction step of bringing an extracted residual liquid obtained in the Al removal step to an equilibrium pH of 6.5 to 7.5 using a solvent containing a carboxylic acid-based extracting agent, extracting at least one of the manganese ions and at least one of the cobalt ions and the nickel ions into the solvent, and then back-extracting the manganese ions and at least one of the cobalt ions and nickel ions.

The present invention relates to an anode active material for lithium secondary battery and a lithium secondary battery including the same, and more specifically it relates to an anode active material for lithium secondary battery in which the a lithium ion diffusion path in the primary particles is formed to exhibit specific directivity, and a lithium secondary battery including the same. The cathode active material for lithium secondary battery of the present invention has a lithium ion diffusion path exhibiting specific directivity in the primary particles and the secondary particles, thus not only the conduction velocity of the lithium ion is fast and the lithium ion conductivity is high but also the cycle characteristics are improved as the crystal structure hardly collapses despite repeated charging and discharging.

A lithium-ion battery includes: a cathode; an anode; and a non-aqueous electrolyte solution, in which the cathode includes a current collector and a cathode mixture applied on at least one side of the current collector, the cathode mixture includes a lithium transition metal oxide as a cathode active material, the anode includes a lithium titanium complex oxide as an anode active material, and the non-aqueous electrolyte solution includes a fluorine-containing boric acid ester.

A method for forming a cathode includes milling a suspension of precursors via a micromedia mill to form a mixture of primary particles in the suspension. The precursors include one or more metal compounds. The method includes spray drying the suspension after the milling to form secondary particles. The secondary particles are agglomerations of the primary particles. The method also includes annealing the secondary particles to form a disordered rocksalt powder.

A compound containing Sn, Te and Mn, and further containing either one or both of Sb and Bi.