Core-shell composite positive electrode material coated with mixed polymer, its preparation method and application in lithium ion battery

Abstract

The invention discloses a mixed polymer-coated core-shell composite positive electrode material, a preparation method thereof and application in a lithium ion battery. The composite positive electrodematerial comprises a positive active material core and a mixed polymer shell, wherein the mixed polymer shell is coated on a surface of the core and comprises a mixture of a conductive polymer and anorganic solid polymer. The method comprises the steps of 1) mixing polyethylene oxide and lithium hexafluorophosphate, and performing ball-milling to obtain a mixture A; 2) mixing the positive activematerial and a coupling agent, and performing dry ball-milling to obtain a mixture B; and 3) mixing the mixture A, the mixture B and the conductive polymer, and performing dry ball-milling and calcination to obtain the core-shell composite positive electrode material. The coating layer of the composite positive electrode material can be compatible with electron conductivity and lithium ion conductivity of the material, the internal resistance of the electrode material is effectively reduced, moreover, two materials in the coating layer are high in compatibility, and the coating uniformity isimproved.

Description

technical field [0001] The invention belongs to the technical field of preparation of electrode materials, and relates to a core-shell type composite positive electrode material, its preparation method and application, in particular to a core-shell type composite positive electrode material coated with a mixed polymer, its preparation method and its application in lithium-ion batteries. the use of. Background technique [0002] With the rapid development of electric vehicles, lithium-ion battery materials have been widely used, and the safety of lithium-ion batteries has also received more attention. The longer cruising range of electric vehicles requires lithium-ion batteries to have higher energy density. High-nickel cathode materials have attracted widespread attention because of their high specific capacity, good cycle performance, and low price, and are considered to be one of the most promising cathode materials for lithium-ion batteries. [0003] The main problem of...

AI Technical Summary

Problems solved by technology

Although carbon material coating can improve electronic conductivity and lithium ion conductivity to a certain extent, for high-nickel cathode materials, there are technical difficulties in carbon material coating, and the thermal reduction involved in the preparation process of carbon material coating is inevitable. Or thermal deposition process, which will reduce the nickel ions in the high-nickel cathode material, which will have a serious impact on the performance of the high-nickel cathode material

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