Lithium-rich manganese-based precursor and preparation method thereof, lithium-rich manganese-based positive electrode material and preparation method thereof, and lithium ion battery

Abstract

The invention belongs to the technical field of lithium ion battery secondary batteries, and provides a preparation method of a lithium-rich manganese-based precursor. A fluorine and magnesium co-doped lithium-rich manganese-based precursor is prepared by a double-system co-precipitation method, the preparation method is simple in process and convenient to operate, and magnesium ions and fluorineions can be uniformly doped in a lithium-rich manganese-based material. The invention also provides the lithium-rich manganese-based precursor prepared by the preparation method, a lithium-rich manganese-based positive electrode material prepared from the lithium-rich manganese-based precursor and a lithium ion battery containing the positive electrode material. The lithium-rich manganese-based positive electrode material prepared by the preparation method disclosed by the invention can effectively improve crystal form stability of the material and inhibit voltage attenuation, and the preparedlithium ion battery has very good electrochemical performance.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery secondary batteries, in particular to a homogeneous co-doped lithium-rich manganese-based precursor prepared by element anchoring and a preparation method thereof, a lithium-rich manganese-based positive electrode material and a preparation method thereof, lithium ion battery. Background technique [0002] Lithium-ion batteries have changed the way people live, and these lightweight, rechargeable and powerful batteries are now used in everything from mobile phones to electric vehicles. It can also store vast amounts of energy from the sun and wind, enabling a fossil fuel-free society. It can be said that the emergence of lithium-ion batteries has greatly improved our quality of life, but it is also for this reason that people have higher and higher requirements for batteries. The performance requirements of current lithium-ion batteries such as capacity, safety, and cycle times And s...

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Problems solved by technology

[0006] The existing O-site F doping method is more common method of co-calcination of precursor and LiF or sol-gel homogeneous fluorine doping method; the former method is a gradient doping, the concentration of F from the precursor There is a concentration gradient from the surface to the interior, which cannot make F evenly distributed in the material structure, and this method cannot ensure that F atoms enter the unit cell of the material; the latter method requires complicated preparation steps and harsh conditions , not suitable for industrial production, and the particle size is small, not suitable for the improvement of battery tap density

[0007] The Chinese patent with the publication number CN202010058718.1 discloses a preparation method of a lithium-rich manganese-based positive electrode material. The carbonate precursor is prepared by co-precipitation under microwave irradiation, and then the lithium-rich manganese-based positive electrode is prepared by the method of fractional calcination. materials, this method doped the dopant ions into the precursor by means of co-precipitation, but this method uses single-system element doping, and does not perform effective F doping. It has been verified by experiments that the precursor obtained by doping with this method The distribution of dopant ions in the body is not uniform, it is difficult to form a uniform and stable structure, and the effect of improving the electrochemical performance of lithium-rich manganese-based cathode materials is not good.

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