Provided is a positive electrode active material for a lithium ion secondary battery having favorable cycle characteristics and high capacity. A covering layer containing aluminum and a covering layer containing magnesium are provided on a superficial portion of the positive electrode active material. The covering layer containing magnesium exists in a region closer to a particle surface than the covering layer containing aluminum is. The covering layer containing aluminum can be formed by a sol-gel method using an aluminum alkoxide. The covering layer containing magnesium can be formed as follows: magnesium and fluorine are mixed as a starting material and then subjected to heating after the sol-gel step, so that magnesium is segregated.

An active material particle or anode containing a lithium cobalt oxide and having a diffraction angle peak at an X-ray diffraction angle of 19.2 degrees or more and 19.7 degrees or less by a 2θ method.

An active material particle or anode containing a lithium cobalt oxide and having a diffraction angle peak at an X-ray diffraction angle of 19.2 degrees or more and 19.7 degrees or less by a 2θ method.

A cathode configured to use oxygen as a cathode active material includes: a porous film including a metal oxide, where a porosity of the porous film is about 50 volume percent to about 95 volume percent, based on a total volume of the porous film, and an amount of an organic component in the porous film is 0 to about 2 weight percent, based on a total weight of the porous film.

A method for manufacturing a cobalt based hydroxide carbonate compound having a malachite-rosasite mineral structure, comprising the steps of: providing an first aqueous solution comprising a source of Co, providing a second aqueous solution comprising Na.sub.2CO.sub.3, mixing both solutions in a precipitation reactor at a temperature above 70° C., thereby precipitating a cobalt based hydroxide carbonate compound whilst evacuating from the reactor any CO.sub.2 formed by the precipitation reaction, wherein the residence time of the compound in the reactor is between 1 and 4 hours, and recovering the cobalt based hydroxide carbonate compound. The cobalt based hydroxide carbonate compound is used as a precursor of a lithium cobalt based oxide usable as an active positive electrode material in lithium ion batteries.

Disclosed is a lithium complex oxide sintered plate for use in a positive electrode of a lithium secondary battery. The lithium complex oxide sintered plate has a structure where a plurality of primary grains having a layered rock-salt structure are bonded, and has a porosity of 3 to 30%, a mean pore diameter of 15 μm or less, an open pore rate of 70% or more, and a thickness of 40 to 200 μm. The primary grains have a primary grain diameter of 20 μm or less, the primary grain diameter being a mean diameter of the primary grains, and a pore diameter distribution includes a first peak corresponding to a pore diameter of more than 0 μm to 1.2 μm or less and a second peak corresponding to a pore diameter which is larger than the pore diameter corresponding to the first peak and is 20 μm or less.

Provided is a method for recovering a valuable metal sulfide, the method including: (a) adding limestone to a residual solution including a valuable metal to remove iron and aluminum; (b) adding sulfuric acid and a sulfide to the solution from which the iron and aluminum are removed to recover the valuable metal sulfide; and (c) adding air or sulfuric acid to the solution from which the valuable metal sulfide is recovered to remove sulfur.

Disclosed is a process for coating onto a substrate, including preparing a precursor having a general formula Q.sub.m/nMO.sub.xF.sub.y by a reaction M(OH).sub.x+yHF+m/nQ(OH).sub.n.fwdarw.Q.sup.n+.sub.m/n(MO.sub.xF.sub.y).sup.m−, wherein Q is an onium ion, selected from quaternary alkyl ammonium, quaternary alkyl phosphonium and trialkylsulfonium; M is a metal capable of forming an oxofluorometallate, where M may further comprise one or more additional metal, metalloid, and one or more of phosphorus (P), sulfur (S) and selenium (Se), iodine (I), and arsenic (As) or a combination thereof, and x>0, y>0, m≥1, n≥1; combining the precursor with a lithium ion source and with the substrate, and mixing to form a coating composition comprising a lithium oxofluorometallate having a general formula Li.sub.mMO.sub.xF.sub.y on the substrate. Further disclosed is a core-shell electrode active material including a core capable of intercalating and deintercalating lithium coated with the lithium oxofluorometallate having the general formula Li.sub.mMO.sub.xF.sub.y.

Provided are a metal element-doped positive electrode active material for a high voltage and a preparation method thereof. The positive electrode active material may include a lithium cobalt oxide having a layered crystal structure; and a metal element (M) incorporated into the lithium cobalt oxide in an amount of 0.2 parts by weight to 1 part by weight with respect to 100 parts by weight of the lithium cobalt oxide, wherein the metal element (M) does not form a chemical bond with the elements of the lithium cobalt oxide, and wherein the layered crystal structure in maintained at a positive electrode potential of more than 4.5 V (based on Li potential) when fully charged.

A method of forming a highly purified positive electrode active material is provided. A method of forming a positive electrode active material whose crystal structure is not easily broken even when charge and discharge are repeated is provided. The method of forming a positive electrode active material including lithium and a transition metal includes a first step of preparing a lithium source and a transition metal source and a second step of crushing and mixing the lithium source and the transition metal source to form a composite material. In the first step, a material with a purity of greater than or equal to 99.99% is prepared as the lithium source and a material with a purity of greater than or equal to 99.9% is prepared as the transition metal source. In the second step, crushing and mixing are performed using dehydrated acetone.