Preparation method of lithium-rich manganese-base anode material

Abstract

The invention discloses a preparation method of a lithium-rich manganese-base anode material. A chemical general formula of the lithium-rich manganese-base anode material is xLi2MnO3<-(1-x)> Limo2, wherein x is larger than or equal to 0 and smaller than or equal to 1, and M adopts transition metal elements of Ni, Co and Mn. The preparation method of the lithium-rich manganese-base anode material comprises the steps as follows: (1), a transition metal salt solution is prepared; (2), a precipitant solution is prepared; (3), the metal salt solution is subjected to ultrasonic atomization and then sprayed into the precipitant solution, and stirring is performed while spraying is performed; (4), the stirring is stopped, still standing is performed, and a precipitated product after reaction is washed to obtain a transition metal precursor; (5), the transition metal precursor and Li salt are mixed, subjected to ball milling in a dispersing agent and dried to obtain a precursor; and (6), the precursor is sintered at the high temperature and cooled to obtain the lithium-rich manganese-base anode material product. According to the invention, the transition metal precursor with higher chemical homogeneity and smaller particle size is prepared in a spraying manner, and the lithium-rich manganese-base anode material with higher electrochemistry capacity, lower capacity fading and better rate capability is obtained after sintering.

Description

technical field [0001] The invention relates to the technical field of preparation of lithium-ion battery materials, in particular to a preparation method of a lithium-rich manganese-based positive electrode material. Background technique [0002] In recent years, lithium-rich manganese-based cathode materials have attracted extensive attention from researchers due to their advantages such as high capacity, high energy density, low price, and abundant raw material sources. In order to promote the practical application of lithium-rich manganese-based cathode materials in lithium-ion batteries, it is necessary to solve their shortcomings such as low coulombic efficiency, poor cycle life, and low rate performance from the perspective of materials. Studies have shown that the mixing of transition cations in the material will reduce the structure instability of the material, which is also one of the main reasons for the shortcomings of the lithium-rich manganese-based cathode mat...

AI Technical Summary

Problems solved by technology

In the traditional solid-phase synthesis of lithium-rich manganese-based cathode materials, due to the large mixing scale in the raw material mixing stage, some raw materials are mixed unevenly, which increases the degree of cation mixing, resulting in poor electrical properties of the material.

Although the performance of the reported sol-gel method is acceptable, it is difficult to promote industrial production.

The production cost of the liquid phase co-precipitation method is relatively low, and the cation mixing degree of the synthesized product by this method is small, the electrochemical performance is superior, and it is more suitable for technological production. Among them, the technical scheme disclosed in Chinese patent application No. 201110067290. The transition metal salt solution, lye and ammonia water are respectively added to the stirrer to stir and heat, and the resulting precipitate is aged, filtered, washed and dried to obtain the nickel-cobalt-manganese precursor, which is mixed with lithium salt and then sintered to improve the heating efficiency. The electrochemical performance of the material is improved, and the particle size of the product evaluation is uniform, and the cycle performance is excellent. However, the flux added in this method to improve the heating efficiency needs to be washed and taken out later, which increases the complexity of product synthesis and is difficult for large-scale industrial production.

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