Titanium dioxide coated lithium nickel cobalt manganate cathode material and preparation method thereof

Abstract

The invention discloses a titanium dioxide coated lithium nickel cobalt manganate cathode material, the thickness of the titanium dioxide layer coated on the surface of the lithium nickel cobalt manganate powder is 10 nm to 1 mum, Lithium nickel cobalt manganate powder was deposited on the surface of lithium nickel cobalt manganate powder by pulsed microwave excitation, and titanium dioxide coatedlithium nickel cobalt manganate cathode material was prepared. The titanium dioxide coating layer formed on the surface of the lithium nickel cobalt manganate powder has good uniformity, controllablethickness, convenient operation and implementation of the preparation method, low coating temperature required in the preparation process, short time and easy industrial production; The cathode material prepared by the invention brings excellent electrochemical cycling performance to the lithium ion battery, and the capacity retention rate is greatly improved.

Description

technical field [0001] The invention relates to a lithium ion battery cathode material and a preparation method thereof, in particular to a nickel-cobalt lithium manganese oxide cathode material with surface coating treatment and a preparation method thereof. Background technique [0002] As the energy density requirements for power batteries are further increased, correspondingly, the energy density requirements for positive electrode materials are also getting higher and higher. Among the four mainstream cathode materials: lithium cobalt oxide cannot meet the long-cycle requirements of power batteries due to its short life; lithium iron phosphate has good safety and cycle performance, but its own gram capacity, voltage platform and compaction density are all low , hinder the development of lithium iron phosphate power battery in the market; the cycle and storage performance of lithium manganate also limit its large-scale application; in contrast, nickel cobalt lithium mang...

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Problems solved by technology

Among the four mainstream cathode materials: lithium cobalt oxide cannot meet the long-cycle requirements of power batteries due to its short life; lithium iron phosphate has good safety and cycle performance, but its own gram capacity, voltage platform and compaction density are all low , hinder the development of lithium iron phosphate power battery in the market; the cycle and storage performance of lithium manganate also limit its large-scale application; in contrast, nickel cobalt lithium manganese oxide cathode material has been favored by people due to its high energy density Favored, especially high-nickel-based ternary materials, whose specific capacity can reach 200mAh / g

However, traditional coating methods often face the problems of uneven coating layer, low ionic conductivity and low electronic conductivity of the coating material.

[0004] A surface treatment method for nickel-cobalt lithium manganese oxide cathode material (country: China, publication number: 105932259A, publication date: 2016-9-17) discloses that a lanthanum source and a titanium source are stirred in an alcoholic solvent until they form sol, and then add nickel-cobalt-lithium-manganese-oxide cathode material into the sol system, and then gel-dry and calcinate to obtain nickel-cobalt-lithium-manganese-oxide cathode material coated with lanthanum-titanium composite oxide. Although this method is relatively simple, the coating layer Thickness and uniformity cannot be guaranteed

The preparation method of spinel lithium-rich lithium manganese oxide cathode material coated with titanium dioxide (country: China, publication number: 105932274A, publication date: 2016-9-7) discloses that the spinel-type lithium-rich manganese acid Lithium dioxide-coated lithium manganate cathode material is prepared by sintering lithium powder with titanium dioxide, titanium monoxide, titanous sulfate, titanium trichloride, titanium tetrachloride or butyl titanate. The thickness of the coating layer of this method is the same as It is related to the particles of the coated raw materials, generally the thickness will be relatively large, and the uniformity of the coating is relatively poor

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