Composite precursor for aluminum-containing lithium transition metal oxide and process for preparation of the same
View Patent ↗The present invention provides a powdery composite precursor, which comprises a core of a lithium transition metal oxide, and an aluminum hydroxide-based precipitate layer coated on the surface of the core, and a process to prepare the composite precursor. The preparation process comprises the formation of a water based slurry by dispersing lithium transition metal oxide powder in water, and a precipitation reaction of an aluminum salt solution with a base solution where the lithium transition metal particles act as seed particles, whereby a mechanically stable precipitate layer of homogeneous thickness can be achieved. The composite precursor can be converted into aluminum-containing, e.g., aluminum-doped, lithium transition metal oxide suitable for a cathode active material of lithium rechargeable battery by heat treatment.
1. A composite precursor for an aluminum-containing lithium transition metal oxide, the composite precursor comprising: (a) a lithium transition metal oxide core, and (b) an aluminum hydroxide-based precipitate layer comprising an active aluminum phase coated on the surface of the lithium transition metal oxide core, wherein the aluminum hydroxide-based precipitate contains a divalent anion, and wherein the divalent anion is carbonate and the aluminum hydroxide-based precipitate layer comprises a lithium-aluminum-carbonate-hydroxide-hydrate.
2. The composite precursor according to claim 1 , wherein the total amount of aluminum in the precipitate layer is 0.5 to 5% by atoms in respect to the total amount of transition metal in the complex precursor.
3. The composite precursor according to claim 1 , wherein the lithium transition metal oxide as the core of composite precursor has a layered or spinel crystal structure.
4. An aluminum-containing lithium transition metal oxide for a cathode active material of lithium rechargeable battery, produced by heating the composite precursor of claim 1 in the range of 500˜1050° C.
5. The aluminum-containing lithium transition metal oxide according to claim 4 , wherein the temperature of heat treatment is 750˜950° C.