Preparation method for power NCM523 material capable of improving high-and-low-temperature performance

Abstract

The invention relates to a preparation method for a power NCM523 material capable of improving high-and-low-temperature performance, and belongs to the technical field of a positive electrode material of a lithium ion battery. The preparation method comprises the following steps of 1, preparation of an NCM523 precursor, including the sub steps of 1) solution preparation: preparing a mixed solution of Ni, Co, Mn and Y salt; preparing an NaOH alkali solution, adding Al(NO<3>)<3>.9H<2>O, and adding ammonium hydroxide to form an aluminum-containing ammonia alkali solution; 2) parallel flow reaction: performing a parallel flow reaction on the Ni, Co, Mn and Y salt solution and the aluminum-containing ammonia alkali solution in a reaction kettle to form a sky blue turbid liquid; 3) aging: regulating the ph value of the solution to perform aging and crystal type transformation; 4) performing pressing and filtering, washing and drying; and 5) performing demagnetizing; 2, lithium preparing and sintering: enabling a lithium salt to be mixed with a precursor material, and performing sintering and smashing on the mixture to obtain the positive electrode material; and 3, performing liquid phase coating of a lithium rapid ion conductor: enabling Li<3>PO<4>-Al(OH)<3> to be mixed with the positive electrode material, and performing spraying and drying, and sintering. The preparation method has the advantages of simple process, convenient operation, and capability of remarkably improving the high-and-low-temperature performance, and the like.

Description

technical field [0001] The invention belongs to the technical field of positive electrode materials of lithium ion batteries, and in particular relates to a preparation method of a power NCM523 material with improved high and low temperature performance. Background technique [0002] At present, lithium-ion batteries, as the core components of the power source of new energy vehicles, are playing an increasingly important role. As an important part of lithium-ion batteries, cathode materials have a great influence on the performance of lithium-ion batteries. At present, lithium-ion batteries for vehicles mainly include ternary material batteries, lithium manganese oxide batteries, lithium iron phosphate batteries, etc. Due to different performances, the application fields of cathode materials are more differentiated. The Ministry of Industry and Information Technology proposed in 2015 that the specific energy of a single lithium-ion battery should be increased to more than 1...

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Problems solved by technology

[0004] After searching, it is found that the application number is 201310726770.X, the publication number is CN103682319A, and the invention patent named "NCM523 ternary material and its preparation method for long-term high-temperature cycle nickel-cobalt manganese oxide", in the sintering process of the material, the aluminum salt or Its oxide is added to the oxide of nickel-cobalt-manganese, and then sintered after mixing evenly by dry method. The high-temperature performance of lithium nickel-cobalt-manganese oxide NCM523 is improved by a large amount of Al ion doping, and the high-temperature cycle of lithium-nickel-cobalt-manganese oxide is solved. The problem of poor performance and high-temperature storage performance, this method only solves the problem of high-temperature cycle and storage in one aspect, and does not describe the improvement of the low-temperature performance of the material

The factors affecting the low-temperature performance of the material are not the diffusion process of lithium ions inside the electrode material, but the polarization caused by the process of lithium ions passing through the active material / electrolyte interface and the charge transfer process. Without modifying the material interface, the effect of simultaneously improving the high and low temperature properties of the material cannot be achieved

At the same time, the present invention carries out a large amount of doping by adding an aluminum source, which can easily cause the accumulation of Al elements on the surface of the material, form an inert layer, affect the activity of the material, and cause technical problems such as capacity decline and long-term cycle deterioration.

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