Preparation method for MOF derived oxide coated NCA high nickel ternary cathode material

Abstract

The invention discloses a preparation method for an MOF derived oxide coated NCA high nickel ternary cathode material and belongs to the technical field of a lithium ion battery. The preparation method comprises the steps of (1), preparing corresponding metal organic frameworks (MOFs) containing specific metal elements; (2), mixing an NCA high nickel ternary cathode material with the specific MOFsaccording to a mass ratio, and carrying out ball milling, thereby enabling the MOFs to be attached to the surface of the NCA high nickel ternary cathode material uniformly; and (3), calcining the material in air, thereby changing a coating material from the MOFs to MOF derived oxides, and obtaining a final product. According to the method, through utilization of features of the nano-material MOFs, a coating layer is kept at a nano-level, so the surface of the material is protected, side reaction due to direct contact with electrolyte is reduced, and battery performance of the cathode materialis improved. The method is novel and convenient and is obvious in effect.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a method for preparing a MOF-derived oxide-coated nickel-cobalt-aluminum ternary positive electrode material. [0002] Background technique: [0003] With the advancement of human science and technology and the improvement of people's living standards, private cars have become more and more popular. However, the extensive use of automobiles will inevitably cause a large amount of exhaust emissions, which will lead to excessive emissions of greenhouse gases into the atmosphere, which will easily cause a series of problems such as global warming. The emergence of new energy vehicles can solve or alleviate this problem to some extent. For electric vehicles, the technical barrier lies in the research and development of battery materials. Nickel-cobalt-manganese (NCM) and nickel-cobalt-aluminum (NCA) ternary cathode materials are considered to be the main cathode materi...

AI Technical Summary

Problems solved by technology

[0010] 4. From the perspective of charge and discharge, the voltage decay and Li loss of NCM materials after charge and discharge cycles are significantly higher than those of NCA materials. The content of Ni2+ in the medium is higher, and the radius of Ni2+ is 0.69A, which is very close to 0.76A of Li+, so Li / Ni mixing is more likely to occur, especially when cycling at a high voltage of 4.4V, the degree of de-Li of the material is higher, and further Promotes Li / Ni mixing, eventually forming spinel and rock salt structures, leading to a significant increase in interfacial charge exchange resistance and a decrease in reversible capacity

[0011] 5. NCM materials are facing problems such as the dissolution of transition metal elements and the migration of dissolved transition metals to the surface of the negative electrode during the cycle, resulting in the continuous growth of the negative electrode SEI film.